Assessing the properties of patient-specific treatment effect estimates from causal forest algorithms under essential heterogeneity

BACKGROUND

Treatment variation from observational data has been used to estimate patient-specific treatment effects. Causal Forest Algorithms (CFAs) developed for this task have unknown properties when treatment effect heterogeneity from unmeasured patient factors influences treatment choice - essential heterogeneity.

METHODS

We simulated eleven populations with identical treatment effect distributions based on patient factors. The populations varied in the extent that treatment effect heterogeneity influenced treatment choice. We used the generalized random forest application (CFA-GRF) to estimate patient-specific treatment effects for each population. Average differences between true and estimated effects for patient subsets were evaluated.

RESULTS

CFA-GRF performed well across the population when treatment effect heterogeneity did not influence treatment choice. Under essential heterogeneity, however, CFA-GRF yielded treatment effect estimates that reflected true treatment effects only for treated patients and were on average greater than true treatment effects for untreated patients.

CONCLUSIONS

Patient-specific estimates produced by CFAs are sensitive to why patients in real-world practice make different treatment choices. Researchers using CFAs should develop conceptual frameworks of treatment choice prior to estimation to guide estimate interpretation ex post.

ICD-10 diagnosis codes in electronic health records do not adequately capture fracture complexity for proximal humerus fractures

BACKGROUND

The ability to do comparative effectiveness research (CER) for proximal humerus fractures (PHF) using data in electronic health record (EHR) systems and administrative claims databases was enhanced by the 10th revision of the International Classification of Diseases (ICD-10), which expanded the diagnosis codes for PHF to describe fracture complexity including displacement and the number of fracture parts. However, these expanded codes only enhance secondary use of data for research if the codes selected and recorded correctly reflect the fracture complexity. The objective of this project was to assess the accuracy of ICD-10 diagnosis codes documented during routine clinical practice for secondary use of EHR data.

METHODS

A sample of patients with PHFs treated by orthopedic providers across a large, regional health care system between January 1, 2016, and December 31, 2018, were retrospectively identified from the EHR. Four fellowship-trained orthopedic surgeons reviewed patient radiographs and recorded the Neer Classification characteristics of displacement, number of parts, and fracture location(s). The fracture characteristics were then reviewed by a trained coder, and the most clinically appropriate ICD-10 diagnosis code based on the number of fracture parts was assigned. We assessed congruence between ICD-10 codes documented in the EHR and radiograph-validated codes, and assessed sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for EHR-documented ICD-10 codes.

RESULTS

There were 761 patients with unilateral, closed PHF who met study inclusion criteria. On average, patients were 67 years of age and 77% were female. Based on radiograph review, 37% were 1-part fractures, 42% were 2-part, 11% were 3-part, and 10% were 4-part fractures. Of the EHR diagnosis codes recorded during clinical practice, 59% were "unspecified" fracture diagnosis codes that did not identify the number of fracture parts. Examination of fracture codes revealed PPV was highest for 1-part (PPV = 0.66, 95% confidence interval [CI] 0.60-0.72) and 4-part fractures (PPV = 0.67, 95% CI 0.13-1.00).

CONCLUSIONS

Current diagnosis coding practices do not adequately capture the fracture complexity needed to conduct subgroup analysis for PHF. Conclusions drawn from population studies or large databases using ICD-10 codes for PHF classification should be interpreted within this limitation. Future studies are warranted to improve diagnostic coding to support large observational studies using EHR and administrative claims data.

Patient preferences as human factors for health data recommender systems and shared decision making in orthopaedic practice

Background

A core set of requirements for designing AI-based Health Recommender Systems (HRS) is a thorough understanding of human factors in a decision-making process. Patient preferences regarding treatment outcomes can be one important human factor. For orthopaedic medicine, limited communication may occur between a patient and a provider during the short duration of a clinical visit, limiting the opportunity for the patient to express treatment outcome preferences (TOP). This may occur despite patient preferences having a significant impact on achieving patient satisfaction, shared decision making and treatment success. Inclusion of patient preferences during patient intake and/or during the early phases of patient contact and information gathering can lead to better treatment recommendations.

Aim

We aim to explore patient treatment outcome preferences as significant human factors in treatment decision making in orthopedics. The goal of this research is to design, build, and test an app that collects baseline TOPs across orthopaedic outcomes and reports this information to providers during a clinical visit. This data may also be used to inform the design of HRSs for orthopaedic treatment decision making.

Methods

We created a mobile app to collect TOPs using a direct weighting (DW) technique. We used a mixed methods approach to pilot test the app with 23 first-time orthopaedic visit patients presenting with joint pain and/or function deficiency by presenting the app for utilization and conducting qualitative interviews and quantitative surveys post utilization.

Results

The study validated five core TOP domains, with most users dividing their 100-point DW allocation across 1-3 domains. The tool received moderate to high usability scores. Thematic analysis of patient interviews provides insights into TOPs that are important to patients, how they can be communicated effectively, and incorporated into a clinical visit with meaningful patient-provider communication that leads to shared decision making.

Conclusion

Patient TOPs may be important human factors to consider in determining treatment options that may be helpful for automating patient treatment recommendations. We conclude that inclusion of patient TOPs to inform the design of HRSs results in creating more robust patient treatment profiles in the EHR thus enhancing opportunities for treatment recommendations and future AI applications.

Unanticipated Costs Associated with Interscalene Nerve Catheters for Shoulder Surgery

BACKGROUND

Regional anesthesia has become a mainstay of analgesia following shoulder arthroscopic and reconstructive procedures. Local anesthetic can be injected in the perineural space of the brachial plexus by a single shot or continuously by an indwelling catheter. Although previous studies have compared efficacy and direct cost of single shot to catheters, few have evaluated unanticipated costs of on-going care or complications. Pulmonary complications can lead to unexpected admissions and emergency room visits. The purpose of the study was to identify unplanned hospital admissions or emergency room visits related to regional anesthesia after shoulder surgery and determine the additional associated costs.

METHODS

A series of 1888 shoulder surgeries were identified in 1856 unique patients at a single large academic center. As part of an interscalene nerve catheter program, a continuous interscalene block (CIB) was given to 1728 patients; whereas, 160 patients had a single shot interscalene block (SSIB). A hospital-employed quality control nurse contacted all patients receiving a CIB at one, two, seven, and fourteen days following surgery. All emergency room visits and readmissions were recorded, and the associated billing charges were reviewed for the inpatient and any outpatient visits immediately preceding or immediately following the readmission. The regional average Medicare fee schedule was used to determine a cost for these episodes of care.

RESULTS

Of the 1728 patients who had CIB, ten patients were readmitted following open or arthroscopic surgery or presented to the emergency department in the immediate postoperative period for pulmonary compromise. No patient in the SSIB group had an emergency room visit or readmission. The average age of the ten patients with readmission was 60 years (7 females, 3 males). The majority were diagnosed with hypoxemia on admission (R09.02). Length of stay during readmission ranged from 0 to 4 days with one patient requiring admission to the ICU. The average cost of admission to the hospital or visit to the emergency room was $6,849 (range, $1,988 to $19,483). These costs were primarily related to chest X-Rays and EKG (9/10), chest CT with contrast (3/10), and head CT (2/10).

CONCLUSION

Although uncommon, unanticipated pulmonary complications after CIB can result in significant cost compared to SSIB. The indirect costs of pulmonary workup after readmission or emergency room work-up may be overlooked if only considering direct costs, such as medication charges, medical supplies, and physician fees.

Uses of Health Care System Medical Care Services by Athletes After Injury at the High School Level

BACKGROUND

Health care utilization can vary by age group, geographic location, and socioeconomic status (SES). A paucity of information exists regarding the availability and utilization of medical care by injured scholastic athletes. The purpose of this study was to describe and compare injuries and health care service utilization by school SES over an academic year.

METHODS

Injury and health care service data was collected from 1 large school district. Percentage of free and reduced lunch (FRPL) for each school was calculated to stratify schools into high (<50% FRPL) and low (≥50.1% FRPL) SES groups. Incidence proportion and relative risk (RR) with 95% confidence intervals (95% CI) were calculated.

RESULTS

About 1756 injuries were reported among over 7000 participating athletes from 14 high schools. Similar injury incidence proportions were reported between high and low SES schools (RR = 1.10 [1.00-1.20]). Athletes from low SES schools were twice (RR = 2.01 [1.21-3.35]) and over three (RR = 3.42 [1.84-6.55]) times more likely to receive emergency and physical therapy care. SES was not associated with the use of physician, imaging, or surgery services.

IMPLICATIONS FOR SCHOOL HEALTH, POLICY, AND EQUITY

School medical providers and administrators should have ready and provide a list of trusted outside primary care and specialty providers that have experience in sports medicine. They should also enquire and follow up on which outside provider the high school athlete will seek care when referring out to outside providers.

CONCLUSIONS

Injury incidence was similar between high and low SES schools. However, athletes from low SES high schools were over 2-fold more likely to use emergency department services. Understanding factors influencing health care services choice and usage by student athletes from different socioeconomic backgrounds may assist sport medicine clinicians in identifying barriers and potential solutions in improving time to health restoration, athlete outcomes, and health care monetary burden.

Assessing the ability of an instrumental variable causal forest algorithm to personalize treatment evidence using observational data: the case of early surgery for shoulder fracture

Background

Comparative effectiveness research (CER) using observational databases has been suggested to obtain personalized evidence of treatment effectiveness. Inferential difficulties remain using traditional CER approaches especially related to designating patients to reference classes a priori. A novel Instrumental Variable Causal Forest Algorithm (IV-CFA) has the potential to provide personalized evidence using observational data without designating reference classes a priori, but the consistency of the evidence when varying key algorithm parameters remains unclear. We investigated the consistency of IV-CFA estimates through application to a database of Medicare beneficiaries with proximal humerus fractures (PHFs) that previously revealed heterogeneity in the effects of early surgery using instrumental variable estimators.

Methods

IV-CFA was used to estimate patient-specific early surgery effects on both beneficial and detrimental outcomes using different combinations of algorithm parameters and estimate variation was assessed for a population of 72,751 fee-for-service Medicare beneficiaries with PHFs in 2011. Classification and regression trees (CART) were applied to these estimates to create ex-post reference classes and the consistency of these classes were assessed. Two-stage least squares (2SLS) estimators were applied to representative ex-post reference classes to scrutinize the estimates relative to known 2SLS properties.

Results

IV-CFA uncovered substantial early surgery effect heterogeneity across PHF patients, but estimates for individual patients varied with algorithm parameters. CART applied to these estimates revealed ex-post reference classes consistent across algorithm parameters. 2SLS estimates showed that ex-post reference classes containing older, frailer patients with more comorbidities, and lower utilizers of healthcare were less likely to benefit and more likely to have detriments from higher rates of early surgery.

Conclusions

IV-CFA provides an illuminating method to uncover ex-post reference classes of patients based on treatment effects using observational data with a strong instrumental variable. Interpretation of treatment effect estimates within each ex-post reference class using traditional CER methods remains conditional on the extent of measured information in the data.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01663-0.

Factors related to initial treatment for adhesive capsulitis in the medicare population

BACKGROUND

Primary adhesive capsulitis (AC) is not well understood, and controversy remains about the most effective treatment approaches. Even less is known about the treatment of AC in the Medicare population. We aimed to fully characterize initial treatment for AC in terms of initial treatment utilization, timing of initial treatments and treatment combinations.

METHODS

Using United States Medicare claims from 2010-2012, we explored treatment utilization and patient characteristics associated with initial treatment for primary AC among 7,181 Medicare beneficiaries. Patients with primary AC were identified as patients seeking care for a new shoulder complaint in 2011, with the first visit related to shoulder referred to as the index date, an x-ray or MRI of the shoulder region, and two separate diagnoses of AC (ICD-9-CM codes: 726.00). The treatment period was defined as the 90 days immediately following the index shoulder visit. A multivariable logistic model was used to assess baseline patient factors associated with receiving surgery within the treatment period.

RESULTS

Ninety percent of beneficiaries with primary AC received treatment within 90 days of their index shoulder visit. Physical therapy (PT) alone (41%) and injection combined with PT (34%) were the most common treatment approaches. Similar patient profiles emerged across treatment groups, with higher proportions of racial minorities, socioeconomically disadvantaged and more frail patients favoring injections or watchful waiting. Black beneficiaries (OR = 0.37, [0.16, 0.86]) and those residing in the northeast (OR = 0.36, [0.18, 0.69]) had significantly lower odds of receiving surgery in the treatment period. Conversely, younger beneficiaries aged 66-69 years (OR = 6.75, [2.12, 21.52]) and 70-75 years (OR = 5.37, [1.67, 17.17]) and beneficiaries with type 2 diabetes had significantly higher odds of receiving surgery (OR = 1.41, [1.03, 1.92]).

CONCLUSIONS

Factors such as patient baseline health and socioeconomic characteristics appear to be important for physicians and Medicare beneficiaries making treatment decisions for primary AC.

Frequency and factors associated with foregone and delayed medical care due to COVID-19 among nonelderly US adults from August to December 2020

OBJECTIVES

To estimate the frequency and factors associated with foregone and delayed medical care attributed to the COVID-19 pandemic among nonelderly adults from August to December 2020 in the United States.

METHODS

We used three survey waves from the Urban Institute's Household Pulse Survey (HPS) collected between August 19-31, October 14-26 and December 9-21. The final sample included 155,825 nonelderly (18-64) respondents representing 135,835,598 million individuals in the United States. We used two multivariable logistic regressions to estimate the association between respondents' characteristics and foregone and delayed care.

RESULTS

The frequency of foregone and delayed medical care was 26.9% and 35.9%, respectively. Around 60% of respondents reported difficulties in paying for usual household expenses in the last 7 days. More than half reported several days of mental health issues. The regression results indicated that foregone or delayed care were significantly associated with difficulties in paying usual household expenses (p < 0.001), worse self-reported health status (p < 0.001), increased mental health problems (p < 0.001), Veterans Affairs (p <0.001) or Medicaid (p = 0.003) coverage compared to private healthcare coverage, and older age groups. Individuals who participated in the latter two waves of the survey (October, December) were less likely to report foregone and delayed care compared to those who participated in Wave 1 (August).

CONCLUSION

Overall, the frequency of foregone and delayed medical care remained high from August to December 2020 among nonelderly US adults. Our findings highlight that pandemic-induced access barriers are major drivers of reduced healthcare provision during the second half of the pandemic and highlight the need for policies to support patients in seeking timely care.

Regenesorb and polylactic acid hydroxyapatite anchors are associated with similar osseous integration and rotator cuff healing at 2 years

BACKGROUND

Commercially available suture anchors for rotator cuff repairs can differ significantly in architecture and material. Clinical data on their osseous integration and its effect on patient-reported outcomes is scarce. Preclinical investigations indicated a higher rate of osseous integration for the open-architecture design of the Healicoil Regenesorb anchor than the closed-threaded design of the Twinfix (Smith & Nephew). The purpose of this study was to investigate these 2 anchors with different architecture and material to determine their effect on osseous integration and clinical outcomes after rotator cuff repair.

METHODS

A prospective randomized controlled trial was performed from 2014 to 2019. Sixty-four patients (39 females, 25 males) with an average age of 58.7 years who underwent arthroscopic rotator cuff repair by one of 4 board-certified, fellowship-trained surgeons were randomized to receive Healicoil Regenesorb (PLGA/ß-TCP/Calcium Sulfate) or Twinfix Ultra HA (PLLA/HA) anchors. Thirty-two patients had Healicoil anchors implanted, and 32 patients had Twinfix anchors implanted. Of the 64 patients, 51 returned at 24 months for computed tomographic (CT) examination (25 Twinfix and 26 Healicoil) to determine osteointegration of the anchors. Patient-reported outcomes, including Penn Shoulder Score (PENN), Western Ontario Rotator Cuff Index, visual analog scale, EQ-5D, Single Assessment Numeric Evaluation, Global Rating of Change, were collected at baseline, 6 weeks, 3 months, 6 months, 12 months, and 24 months. Ultrasonography was used to assess rotator cuff integrity after 6 months. Two board-certified, fellowship-trained orthopedic surgeons, blinded to the type of anchors, analyzed the CT scans to assess the anchor osteointegration at 24 months using a previously published grading scale.

RESULTS

There were no differences in demographics, preoperative outcomes, or baseline characteristics such as tear size, number of anchors, Goutallier classification, or smoking status between groups. There was no difference in osseous integration between the 2 anchors at 24 months (P = .117). Eight patients had rotator cuff retears, of which 2 patients had Twinfix anchors and 6 patients had Healicoil anchors (P = .18). There were no statistically significant differences in patient-reported outcomes or complications between groups. The 2-year PENN scores were 89 with the Twinfix and 88 with Healicoil anchors (P = .55).

CONCLUSION

Despite differences in material and anchor architecture, the rate of healing and patient-reported outcomes were similar between the Twinfix and Healicoil anchor groups. The rate of osteointegration was the same at 2 years.

Assessing the Patient-Perceived Monetary Value of Patient-Reported Outcome Improvement for Patients With Chronic Knee Conditions

PURPOSE

The high cost of orthopaedic care has attracted criticism in the current value-based health care environment. The objective of this work was to assess the properties of a willingness to pay (WTP)-based approach to estimate the monetary value that patients place on health improvements in chronic knee conditions following orthopaedic treatment.

METHODS

A sample of patients with a chronic knee condition were surveyed between January and May of 2018 at a large orthopaedic practice. Each patient provided their WTP for restoration to ideal knee health and completed the Single Assessment Numerical Evaluation (SANE) to describe their baseline knee state. Average WTP was calculated for the total sample and stratified by income, age, and baseline SANE (for which 0 is the worst and 100 is the best) levels. The patient-perceived monetary value of each unit of SANE improvement was assessed.

RESULTS

The study sample included 86 patients seeking orthopaedic care for a chronic knee condition. Mean baseline SANE score was 45.5 (standard deviation: 25.0). Mean WTP to obtain ideal knee function from baseline was $18,704 (standard deviation: $18,040). For the full sample, patients valued a 1-unit improvement in SANE score at $291.1 (β: 291.1; P<0.05). The amount of money patients were willing to pay to achieve ideal knee function varied with age, income, and baseline knee state.

CONCLUSIONS

Patients appear to highly value improvement in chronic knee conditions. Willingness-to-pay survey results appear to track expected variation in patient outcome valuation by income and baseline knee condition and could be a valuable approach to assess value-based care in orthopaedics.

Risk Adjustment of the Modified Low Back Pain Disability Questionnaire and Neck Disability Index to Benchmark Physical Therapist Performance: Analysis From an Outcomes Registry

BACKGROUND

Patient-reported outcomes (PROs) have been touted as the ultimate assessment of quality medical care and have been proposed as performance measures after appropriate risk adjustment. Although spine conditions represent the most common orthopedic disorders, the most used PROs for disabilities related to the back and neck-the Modified Low Back Pain Disability Questionnaire (MDQ) and the Neck Disability Index (NDI)-have not been evaluated as performance measures.

OBJECTIVE

The objective of this study was to benchmark physical therapists' performance in the management of spine conditions not involving surgery through the use of risk-adjusted MDQ and NDI outcomes.

DESIGN

This was a retrospective observational study.

METHODS

Data were accessed for patients seeking physical therapy with no history of related surgery for back or neck pain (315,274 treatment episodes) between January 2015 and June 2018. Patients with complete data, including initial and matched final MDQ or NDI, were considered for analysis (182,276 patients; 2799 physical therapists). Linear models controlling for baseline PRO and patient characteristics predicted PRO change for each patient. An aggregated performance ratio of actual PRO change to predicted PRO change was calculated for each physical therapist, and then empirical bootstrapping was used to develop the median performance ratio and its confidence intervals. Physical therapists who met a 40-patient threshold for either cohort (MDQ or NDI) were classified as "outperforming," "meeting expectations," or "underperforming" relative to predicted values using these 95% confidence intervals.

RESULTS

Performance ratios indicated that 10% and 11% of physical therapists outperformed, 79% and 78% met expectations, and 11% and 11% underperformed relative to the risk-adjusted predicted change in the MDQ (1240 therapists; 97,908 patients) and NDI (461 therapists; 26,123 patients), respectively. To demonstrate the clinical importance of risk adjustment, clinical performance was evaluated in the seemingly homogeneous subset of 208 physical therapists within 0.5 SD of the median baseline MDQ and the median actual change in the MDQ. Following risk adjustment, 2 physical therapists were classified in each of the outperforming and underperforming cohorts.

LIMITATIONS

The secondarily obtained observational data used were not collected for research purposes. Additionally, the analyses were limited by missing baseline information and follow-up PROs.

CONCLUSIONS

The risk-adjusted performance ratios for the MDQ and NDI resulted in disparate conclusions regarding the quality of care compared with the raw, unadjusted change scores. According to the baseline and unadjusted change in the MDQ, even physical therapists in the most homogeneous sample were differentiated following appropriate risk adjustment. Clinically important improvements in actual PROs were observed in the outperforming but not in the underperforming physical therapists. Clinically meaningful differences in the performance ratio are unknown and are a limitation to clinical application and an opportunity for future research.

Association of Surgical Treatment With Adverse Events and Mortality Among Medicare Beneficiaries With Proximal Humerus Fracture

IMPORTANCE

Meta-analyses of randomized clinical trials suggest that the advantages and risks of surgery compared with conservative management as the initial treatment for proximal humerus fracture (PHF) vary, or are heterogeneous across patients. Substantial geographic variation in surgery rates for PHF suggests that the optimal rate of surgery across the population of patients with PHF is unknown.

OBJECTIVE

To use geographic variation in treatment rates to assess the outcomes associated with higher rates of surgery for patients with PHF.

DESIGN, SETTING, AND PARTICIPANTS

This comparative effectiveness research study analyzed all fee-for-service Medicare beneficiaries with proximal humerus fracture in 2011 who were continuously enrolled in Medicare Parts A and B for the 365-day period before and immediately after their index fracture. Data analysis was performed January through June 2019.

EXPOSURE

Undergoing 1 of the commonly used surgical procedures in the 60 days after an index fracture diagnosis.

MAIN OUTCOMES AND MEASURES

Risk-adjusted area surgery ratios were created for each hospital referral region as a measure of local area practice styles. Instrumental variable approaches were used to assess the association between higher surgery rates and adverse events, mortality risk, and cost at 1 year from Medicare's perspective for patients with PHF in 2011. Instrumental variable models were stratified by age, comorbidities, and frailty. Instrumental variable estimates were compared with estimates from risk-adjusted regression models.

RESULTS

The final cohort included 72 823 patients (mean [SD] age, 80.0 [7.9] years; 13 958 [19.2%] men). The proportion of patients treated surgically ranged from 1.8% to 33.3% across hospital referral regions in the United States. Compared with conservatively managed patients, surgical patients were younger (mean [SD] age, 80.4 [8.1] years vs 78.0 [7.2] years; P < .001) and healthier (Charlson Comorbidity Index score of 0, 14 863 [24.4%] patients vs 3468 [29.1%] patients; Function-Related Indicator score of 0, 20 720 [34.0%] patients vs 4980 [41.8%] patients; P < .001 for both), and a larger proportion were women (49 030 [80.5%] patients vs 9835 [82.5%] patients; P < .001). Instrumental variable analysis showed that higher rates of surgery were associated with increased total costs ($8913) during the treatment period, increased adverse event rates (a 1-percentage point increase in the surgery rate was associated with a 0.19-percentage point increase in the 1-year adverse event rate; β = 0.19; 95% CI, 0.09-0.27; P < .001), and increased mortality risk (a 1-percentage point increase in the surgery rate was associated with a 0.09-percentage point increase in the 1-year mortality rate; β = 0.09; 95% CI, 0.04-0.15; P < .01). Instrumental variable mortality results were even more striking for older patients and those with higher comorbidity burdens and greater frailty. Risk-adjusted estimates suggested that surgical patients had higher costs (increase of $17 278) and more adverse events (a 1-percentage point increase in the surgery rate was associated with a 0.12-percentage point increase in the 1-year adverse event rate; β = 0.12; 95% CI, 0.11 to 0.13; P < .001) but lower risk of mortality after PHF (a 1-percentage point increase in the surgery rate was associated with a 0.01-percentage point decrease in the 1-year mortality rate; β = -0.01; 95% CI, -0.015 to -0.005; P < .001).

CONCLUSIONS AND RELEVANCE

This study found that higher rates of surgery for treatment of patients with PHF were associated with increased costs, adverse event rates, and risk of mortality. Orthopedic surgeons should be aware of the harms of extending the use of surgery to more clinically vulnerable patient subgroups.

Freestanding Dialysis Facility Quality Incentive Program Scores and Mortality Among Incident Dialysis Patients in the United States

RATIONALE & OBJECTIVE

The Centers for Medicare & Medicaid Services introduced the Quality Incentive Program (QIP) along with the bundled payment reform to improve the quality of dialysis care in the United States. The QIP has been criticized for using easily obtained laboratory indicators without patient-centered measures and for a lack of evidence for an association between QIP indicators and patient outcomes. This study examined the association between dialysis facility QIP performance scores and survival among patients after initiation of dialysis.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Study participants included 84,493 patients represented in the US Renal Disease System's patient-level data who had initiated dialysis between January 1, 2013, and December 1, 2013, and who did not, during the first 90 days after dialysis initiation, die, receive a transplant, or become lost to follow-up. Patients were followed up for the study outcome through March 31, 2014.

PREDICTOR

Dialysis facility QIP scores.

OUTCOME

Mortality.

ANALYTICAL APPROACH

Using a unique facility identifier, we linked Medicare freestanding dialysis facility data from 2015 with US Renal Disease System patient-level data. Kaplan-Meier product limit estimator was used to describe the survival of study participants. Cox proportional hazards regression was used to assess the multivariable association between facility performance scores and patient survival.

RESULTS

Excluding patients who died during the first 90 days of dialysis, 11.8% of patients died during an average follow-up of 5 months. Facilities with QIP scores<45 (HR, 1.39; 95% CI, 1.15-1.68) and 45 to<60 (HR, 1.21; 95% CI, 1.10-1.33) had higher patient mortality rates than facilities with scores≥90.

LIMITATIONS

Because the Centers for Medicare & Medicaid Services have revised QIP criteria each year, the findings may not relate to years other than those studied.

CONCLUSIONS

Dialysis facilities characterized by lower QIP scores were associated with higher rates of patient mortality. These findings need to be replicated to assess their consistency over time.

Reliability of the American Community Survey Estimates of Risk-Adjusted Readmission Rankings for Hospitals Before and After Peer Group Stratification

IMPORTANCE

Since the transition to the American Community Survey, data uncertainty has complicated its use for policy making and research, despite the ongoing need to identify disparities in health care outcomes. The US Centers for Medicare & Medicaid Services' new, stratified payment adjustment method for its Hospital Readmissions Reduction Program may be able to reduce the reliance on data linkages to socioeconomic survey estimates.

OBJECTIVE

To determine whether there are differences in the reliability of socioeconomically risk-adjusted hospital readmission rates among hospitals that serve a disproportionate share of low-income populations after stratifying hospitals into peer group-based classification groups.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study uses data from the 2014 New York State Health Cost and Utilization Project State Inpatient Database for 96 278 hospital admissions for acute myocardial infarction, pneumonia, and congestive heart failure. The analysis included patients aged 18 years and older who were not transferred to another hospital, who were discharged alive, who did not leave the hospital against medical advice, and who were discharged before December 2014.

MAIN OUTCOMES AND MEASURES

The main outcomes were 30-day hospital readmissions after acute myocardial infarction, pneumonia, and congestive heart failure assessed using hierarchical logistic regression.

RESULTS

The mean (SD) age of the patients was 69.6 (16.0) years for the safety-net hospitals and 74.9 (14.7) years for the non-safety-net hospitals; 9382 (48.8%) and 7003 (48.5%) patients, respectively, were female. For safety net designations, 20% (3 of 15) of all evaluations concealed and distorted differences in risk, with factors such as poverty failing to identify similar risk of acute myocardial infarction readmission until unreliable estimates were excluded from the analysis (OR, 1.23 [95% CI, 1.00-1.52], P = .02; vs OR, 1.17 [95% CI, 0.94-1.46], P = .15). By comparison, 2 of the 60 models (3%) for the peer group-based classification altered the association between socioeconomic status and readmission risk, concealing similarities in congestive heart failure readmission when adjusted using high school completion rates (OR, 1.27 [95% CI 1.02-1.58], P = .04; vs OR, 1.23 [95% CI, 0.98-1.53], P = .06) and distorting similarities in pneumonia readmissions when accounting for the proportion of lone-parent families (OR, 1.27 [95% CI, 0.98-1.66], P = .07; vs OR, 1.35 [95% CI, 1.02-1.80], P = .04) between the lowest and highest socioeconomic status hospitals in quartile 1.

CONCLUSIONS AND RELEVANCE

There was greater precision in socioeconomic adjusted readmission estimates when hospitals were stratified into the new payment adjustment criteria compared with safety net designations. A contributing factor for improved reliability of American Community Survey estimates under the new payment criteria was the merging of patients from low-income neighborhoods with greater homogeneity in survey estimates into groupings similar to those for higher-income patients, whose neighborhoods often exhibit greater estimate variability. Additional efforts are needed to explore the effect of measurement error on American Community Survey-adjusted readmissions using the new peer group-based classification methods.

Comparison of Surgeon Performance of Rotator Cuff Repair: Risk Adjustment Toward a More Accurate Performance Measure

BACKGROUND

Movement toward a value-based health-care system necessitates the development of performance measures to compare physicians, hospitals, and health-care systems. Patient-reported outcomes (PROs) are a potential metric. However, valid use of PROs hinges on the ability to risk-adjust for baseline patient differences across a surgeon's panel of patients. The purpose of this study was to propose an approach for baseline risk adjustment and evaluate the importance of risk adjustment when comparing surgeons' performance of rotator cuff repair.

METHODS

Patients (n = 995) treated with arthroscopic rotator cuff repair by 34 surgeons from 2010 to 2017 were identified from a large sports medicine clinical data registry. A linear regression model was used to adjust for baseline PROs, patient demographics, and clinical characteristics to predict American Shoulder and Elbow Surgeons (ASES) change scores for each surgeon. A risk-adjusted performance measure was calculated as the difference between the average unadjusted ASES change scores and the risk-adjusted predicted ASES change scores across all patients treated by a surgeon.

RESULTS

The differences between unadjusted and risk-adjusted performance scores varied widely across surgeons (range, -13.8 to 10.3 ASES points). Use of the risk-adjusted performance scores resulted in a dramatic change in the relative ranking of surgeons, compared with the ranking based on the observed ASES change scores, with 31 of the 34 surgeons' rank changing following risk adjustment. On average, the observed ASES scores improved from 49.5 ± 17.5 at baseline to 78.0 ± 22.5 at 6 months across all surgeons. In the risk-adjustment model (R = 0.44), male sex, Workers' Compensation status, higher scores on the Veterans RAND 12-item Health Survey (VR-12), lower baseline ASES scores, fair and poor tendon quality, and night pain all had a significant effect on the predicted ASES change scores (p < 0.05).

CONCLUSIONS

Our results show wide variation of nearly 25 points in the risk-adjusted 6-month ASES performance difference from the highest to the lowest-performing surgeons. Additionally, 91% of surgeons' rank changed following risk adjustment. This suggests that performance measurement that does not account for baseline patient characteristics would likely result in incorrect conclusions about a surgeon's relative performance based on PROs.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A comparison of one-year treatment utilization for shoulder osteoarthritis patients initiating care with non-orthopaedic physicians and orthopaedic specialists

Background

In this paper we investigate patients seeking care for a new diagnosis of shoulder osteoarthritis (OA) and the association between a patient’s initial physician specialty choice and one-year surgical and conservative treatment utilization.

Methods

Using retrospective data from a single large regional healthcare system, we identified 572 individuals with a new diagnosis of shoulder OA and identified the specialty of the physician which was listed as the performing physician on the index shoulder visit. We assessed treatment utilization in the year following the index shoulder visit for patients initiating care with a non-orthopaedic physician (NOP) or an orthopaedic specialist (OS). Descriptive statistics were calculated for each group and subsequent one-year surgical and conservative treatment utilization was compared between groups.

Results

Of the 572 patients included in the study, 474 (83%) received care from an OS on the date of their index shoulder visit, while 98 (17%) received care from a NOP. There were no differences in baseline patient age, gender, BMI or pain scores between groups. OS patients reported longer symptom duration and a higher rate of comorbid shoulder diagnoses. Patients initiating care with an OS on average received their first treatment much faster than patients initiating care with NOP (16.3 days [95% CI, 12.8, 19.7] vs. 32.3 days [95% CI, 21.0, 43.6], Z = 4.9, p < 0.01). Additionally, patients initiating care with an OS had higher odds of receiving surgery (OR = 2.65, 95% CI: 1.42, 4.95) in the year following their index shoulder visit.

Conclusions

Patients initiating care with an OS received treatment much faster and were treated with more invasive services over the year following their index shoulder visit. Future work should compare patient-reported outcomes across patient groups to assess whether more expensive and invasive treatments yield better outcomes for patients with shoulder OA.

Treatment for Rotator Cuff Tear Is Influenced by Demographics and Characteristics of the Area Where Patients Live

Background:

Atraumatic rotator cuff tear is a common orthopaedic complaint for people >60 years of age. Lack of evidence or consensus on appropriate treatment for this type of injury creates the potential for substantial discretion in treatment decisions. To our knowledge, no study has assessed the implications of this discretion on treatment patterns across the United States.

Methods:

All Medicare beneficiaries in the United States with a new magnetic resonance imaging (MRI)-confirmed atraumatic rotator cuff tear were identified with use of 2010 to 2012 Medicare administrative data and were categorized according to initial treatment (surgery, physical therapy, or watchful waiting). Treatment was modeled as a function of the clinical and demographic characteristics of each patient. Variation in treatment rates across hospital referral regions and the presence of area treatment signatures, representing the extent that treatment rates varied across hospital referral regions after controlling for patient characteristics, were assessed. Correlations between measures of area treatment signatures and measures of physician access in hospital referral regions were examined.

Results:

Among patients who were identified as having a new, symptomatic, MRI-confirmed atraumatic rotator cuff tear (n = 32,203), 19.8% were managed with initial surgery; 41.3%, with initial physical therapy; and 38.8%, with watchful waiting. Patients who were older, had more comorbidity, or were female, of non-white race, or dual-eligible for Medicaid were less likely to receive surgery (p < 0.0001). Black, dual-eligible females had 0.42-times (95% confidence interval [CI], 0.34 to 0.50) lower odds of surgery and 2.36-times (95% CI, 2.02 to 2.70) greater odds of watchful waiting. Covariate-adjusted odds of surgery varied dramatically across hospital referral regions; unadjusted surgery and physical therapy rates varied from 0% to 73% and from 6% to 74%, respectively. On average, patients in high-surgery areas were 62% more likely to receive surgery than the average patient with identical measured characteristics, and patients in low-surgery areas were half as likely to receive surgery than the average comparable patient. The supply of orthopaedic surgeons and the supply of physical therapists were associated with greater use of initial surgery and physical therapy, respectively.

Conclusions:

Patient characteristics had a significant influence on treatment for atraumatic rotator cuff tear but did not explain the wide-ranging variation in treatment rates across areas. Local-area physician supply and specialty mix were correlated with treatment, independent of the patient’s measured characteristics.

Understanding Treatment Effect Estimates When Treatment Effects Are Heterogeneous for More Than One Outcome

BACKGROUND

Patient-centred care requires evidence of treatment effects across many outcomes. Outcomes can be beneficial (e.g. increased survival or cure rates) or detrimental (e.g. adverse events, pain associated with treatment, treatment costs, time required for treatment). Treatment effects may also be heterogeneous across outcomes and across patients. Randomized controlled trials are usually insufficient to supply evidence across outcomes. Observational data analysis is an alternative, with the caveat that the treatments observed are choices. Real-world treatment choice often involves complex assessment of expected effects across the array of outcomes. Failure to account for this complexity when interpreting treatment effect estimates could lead to clinical and policy mistakes.

OBJECTIVE

Our objective was to assess the properties of treatment effect estimates based on choice when treatments have heterogeneous effects on both beneficial and detrimental outcomes across patients.

METHODS

Simulation methods were used to highlight the sensitivity of treatment effect estimates to the distributions of treatment effects across patients across outcomes. Scenarios with alternative correlations between benefit and detriment treatment effects across patients were used. Regression and instrumental variable estimators were applied to the simulated data for both outcomes.

RESULTS

True treatment effect parameters are sensitive to the relationships of treatment effectiveness across outcomes in each study population. In each simulation scenario, treatment effect estimate interpretations for each outcome are aligned with results shown previously in single outcome models, but these estimates vary across simulated populations with the correlations of treatment effects across patients across outcomes.

CONCLUSIONS

If estimator assumptions are valid, estimates across outcomes can be used to assess the optimality of treatment rates in a study population. However, because true treatment effect parameters are sensitive to correlations of treatment effects across outcomes, decision makers should be cautious about generalizing estimates to other populations.

Use of Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers for Geriatric Ischemic Stroke Patients: Are the Rates Right?

BACKGROUND

Our objective is to estimate the effects associated with higher rates of renin-angiotensin system antagonists, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers (ACEI/ARBs), in secondary prevention for geriatric (aged >65 years) patients with new ischemic strokes by chronic kidney disease (CKD) status.

METHODS AND RESULTS

The effects of ACEI/ARBs on survival and renal risk were estimated by CKD status using an instrumental variable (IV) estimator. Instruments were based on local area variation in ACEI/ARB use. Data abstracted from charts were used to assess the assumptions underlying the instrumental estimator. ACEI/ARBs were used after stroke by 45.9% and 45.2% of CKD and non-CKD patients, respectively. ACEI/ARB rate differences across local areas grouped by practice styles were nearly identical for CKD and non-CKD patients. Higher ACEI/ARB use rates for non-CKD patients were associated with higher 2-year survival rates, whereas higher ACEI/ARB use rates for patients with CKD were associated with lower 2-year survival rates. While the negative survival estimates for patients with CKD were not statistically different from zero, they were statistically lower than the estimates for non-CKD patients. Confounders abstracted from charts were not associated with the instrumental variable used.

CONCLUSIONS

Higher ACEI/ARB use rates had different survival implications for older ischemic stroke patients with and without CKD. ACEI/ARBs appear underused in ischemic stroke patients without CKD as higher use rates were associated with higher 2-year survival rates. This conclusion is not generalizable to the ischemic stroke patients with CKD, as higher ACEI/ARBS use rates were associated with lower 2-year survival rates that were statistically lower than the estimates for non-CKD patients.

Shoulder arthroplasty in the US Medicare population: a 1-year evaluation of surgical complications, hospital admissions, and revision surgery

Background

The objective of this study was to describe patients receiving each shoulder arthroplasty procedure and to assess surgical complications, hospital admissions for surgical complications, and surgical revisions among Medicare beneficiaries undergoing shoulder arthroplasty.

Methods

Medicare patients receiving shoulder arthroplasty in the United States in 2011 were identified from Medicare administrative data and classified by surgery type: shoulder hemiarthroplasty (HA), anatomic total shoulder arthroplasty (TSA), or reverse shoulder arthroplasty (RSA). Surgical complications, hospital admissions, and revisions were identified during the year after the index arthroplasty procedure.

Results

There were 24,441 patients who met all inclusion criteria, and of those, 20.0% received HA, 42.5% received TSA, and 37.4% received RSA. Compared with RSA and TSA recipients, HA recipients tended to be older and sicker and were more likely to be Medicaid eligible. The rate of new surgical complications and related hospital admissions was greatest during the first 50 days after surgery but remained significant and stable throughout the remainder of the year. Rates of complications and related hospital admissions were greatest for HA recipients (17.4% and 6.6%, respectively), followed by RSA (14.2% and 5.1%) and TSA (9.4% and 4.0%).

Conclusions

The rate of adverse surgical outcomes after shoulder arthroplasty differed across populations that received HA, TSA, and RSA and across patients within each group by comorbidity burden. The finding that the rate of surgical complications and related hospital admissions remained meaningful during the entire year after surgery suggests that a postoperative follow-up period longer than the traditional 90 days may be warranted.

Depression and Handgrip Strength Among U.S. Adults Aged 60 Years and Older from NHANES 2011-2014

OBJECTIVES

Sarcopenia is a gradual loss of muscle mass and strength that occurs with aging. This muscle deterioration is linked to increased morbidity, disability, and other adverse outcomes. Although reduced handgrip strength can be considered a marker of sarcopenia and other aging-related decline in the elderly, there is limited research on this physical health problem in at-risk groups with common biopsychosocial conditions such as depression. Our primary objective was to ascertain level of combined handgrip strength and its relationship with depression among adults aged 60 years and older.

DESIGN

Unadjusted and adjusted linear regression models were conducted with a cross-sectional survey dataset.

SETTING

Secondary dataset from the 2011-2014 National Health and Nutrition Examination Survey (NHANES).

PARTICIPANTS

Community-dwelling, non-institutionalized adults ≥60 years old (n=3,421).

MEASUREMENTS

The predictor variables included a positive screen for clinically relevant depression (referent=PHQ-9 score <10). The criterion variable of combined handgrip strength (kg) was determined using a dynamometer.

RESULTS

Mean age and BMI were 69.9 years (51.5% female) and 28.8 kg/m2, respectively. Mean combined handgrip strength in the overall cohort was 73.5 and 46.6 kg in males and females, respectively. Three hundred thirty-six (9.8%) reported symptoms of depression. In unadjusted and fully adjusted models, depression was significantly associated with reduced handgrip strength (B = -0.26±0.79 and B = -0.19±0.08, respectively; p<0.001).

CONCLUSION

Our findings demonstrate handgrip strength has a significant inverse association with depression. Future longitudinal studies should investigate the causal processes and potential moderators and mediators of the relationships between depression and reduced handgrip strength. This information may further encourage the use of depression and handgrip strength assessments and aid in the monitoring and implementation of health care services that address both physical and mental health limitations among older adult populations.

Smoking Predicting Physical Activity in an Aging America

OBJECTIVES

Tobacco smoking and physical inactivity are among leading behavioral risk factors for ill health in older adults. This study considers how smoking is associated with physical activity.

DESIGN

Using a Life-Course model, data are analyzed regarding this relationship, controlling for, and interacted with, life-course and other factors. Daily smokers and sometimes smokers were hypothesized to engage in less leisure-time physical activity than those who never smoked, while those who stopped smoking were expected to do more than never smokers. Analyses were performed using SAS-Callable SUDAAN.

SETTING AND PARTICIPANTS

Secondary data from ten years of a national sample of adults aged 18 and over of the National Health Interview Survey, 2001-2010, are used (N = 264,945, missing data excluded, of 282,313 total cases).

MEASUREMENTS

Daily smokers, occasional smokers, and smoking quitters are compared to never smokers with regard to requisite physical activity (150 minutes per week of moderate, 100 of vigorous, and/or 50 of strengthening activity). Life-course measures include birth cohorts, age, and year of survey, as well as gender, race/ethnicity, and education.

RESULTS

Overall, hypotheses are supported regarding daily smokers and quitters; but the hypothesis is strongly rejected among sometimes smokers, who are much more likely to do requisite physical activity. Findings differ by age, sometimes smokers age 65 and over being less likely to do physical activity. Findings among all men are similar to the overall findings, while those among all women are similar to those for older respondents. Associations of smoking status with physical activity vary greatly by race/ethnicity.

CONCLUSIONS

Daily smokers may be most in need of both smoking cessation and leisure-time physical activity interventions. Smoking-cessation efforts may pay greater physical activity benefits among women and the aged, while smoking-reduction efforts may provide better outcomes among men. Smoking reduction efforts may pay more exercise benefits among African-Americans and Hispanics.

Geographic variation in inhaled corticosteroid use for children with persistent asthma in Medicaid

OBJECTIVE

Geographic variation in the rates of inhaled corticosteroid (ICS) use for children with persistent asthma in Medicaid has been reported, but the source of this variation is unknown. The objective of this study was to quantify the geographic variation in ICS use for children with persistent asthma in Medicaid that remains after adjusting for the characteristics of children in an area.

METHODS

Data from the 2005-2007 Medicaid Analytic eXtract files were used. Frequent fills of short-acting beta₂-agonist (SABA) were used to identify children 5-18 years of age with persistent asthma across the United States. A child was considered to have used an ICS if the child initially filled an ICS following frequent SABA use. Areas were determined using published methods, and the unadjusted ICS rate and the area treatment ratio for ICS, which adjusted for demographic and clinical characteristics, were calculated for each area.

RESULTS

Of 15,917 children, 13% used an ICS. The median unadjusted ICS rate for all areas was 10% but ranged from 0% to 64%. ICS use was less than expected for more than half of the areas based on the characteristics of the children in the area, but use was nearly five times what was expected in some areas. Areas with higher than expected ICS use were found contiguous to areas with lower than expected use.

CONCLUSIONS

Geographic variation in ICS not attributable to the demographic and clinical characteristics of the children in an area exists and could prove useful in the struggle to reduce asthma exacerbation rates.

Variation in geographic access to chemotherapy by definitions of providers and service locations: a population-based observational study

Background

An aging population, with its associated rise in cancer incidence and strain on the oncology workforce, will continue to motivate patients, healthcare providers and policy makers to better understand the existing and growing challenges of access to chemotherapy. Administrative data, and SEER-Medicare data in particular, have been used to assess patterns of healthcare utilization because of its rich information regarding patients, their treatments, and their providers. To create measures of geographic access to chemotherapy, patients and oncologists must first be identified. Others have noted that identifying chemotherapy providers from Medicare claims is not always straightforward, as providers may report multiple or incorrect specialties and/or practice in multiple locations. Although previous studies have found that specialty codes alone fail to identify all oncologists, none have assessed whether various methods of identifying chemotherapy providers and their locations affect estimates of geographic access to care.

Methods

SEER-Medicare data was used to identify patients, physicians, and chemotherapy use in this population-based observational study. We compared two measures of geographic access to chemotherapy, local area density and distance to nearest provider, across two definitions of chemotherapy provider (identified by specialty codes or billing codes) and two definitions of chemotherapy service location (where chemotherapy services were proven to be or possibly available) using descriptive statistics. Access measures were mapped for three representative registries.

Results

In our sample, 57.2 % of physicians who submitted chemotherapy claims reported a specialty of hematology/oncology or medical oncology. These physicians were associated with 91.0 % of the chemotherapy claims. When providers were identified through billing codes instead of specialty codes, an additional 50.0 % of beneficiaries (from 23.8 % to 35.7 %) resided in the same ZIP code as a chemotherapy provider. Beneficiaries were also 1.3 times closer to a provider, in terms of driving time. Our access measures did not differ significantly across definitions of service location.

Conclusions

Measures of geographic access to care were sensitive to definitions of chemotherapy providers; far more providers were identified through billing codes than specialty codes. They were not sensitive to definitions of service locations, as providers, regardless of how they are identified, generally provided chemotherapy at each of their practice locations.

Application of a framework for determining number of drugs

Background

There are many different methodologies used in the literature for determining the number of drugs used by a patient, and many are incompletely described. This may be attributable to the lack of a framework to help investigators choose and describe their methods and the lack of evidence on the implications of the choice. The purpose of the study was to propose a framework and illustrate how that framework can be used to create and succinctly describe various approaches to counting the number of drugs used by patients and to examine the impact of varying individual components of the framework on the resulting drug count.

Methods

The three component framework requires specification of scope, uniqueness, and timeframe. The framework was applied to Medicare beneficiaries admitted for acute myocardial infarction in 2008. Drug use was ascertained by Part D prescription drug event files. A default measure for drug count was established, and fourteen additional measures were created by separately altering individual components of the default to illustrate the application of the framework and understand how these changes impacted drug count. Median drug counts and the frequency distributions of beneficiaries experiencing a change in count from default were produced for each measure.

Results

The median drug count for the default measure was 4. Alteration of the timeframe component had the largest impact on drug counts, with a look-back period of 180 days producing a median count of 8 and changing the count by at least two for 73 % of patients. Variations of the other components had less impact.

Conclusion

Our framework is intended to be used by investigators to select an approach to counting number of drugs in their studies. Extending the timeframe over which fills from a pharmacy refill database could be counted toward the drug count produced the greatest changes in the number of drugs.

Association Between Preadmission Functional Status and Use and Effectiveness of Secondary Prevention Medications in Elderly Survivors of Acute Myocardial Infarction

OBJECTIVES

To determine whether function-related indicators (FRIs), derived from preadmission claims data, help explain the frequent practice of forgoing secondary prevention medications observed in Medicare.

DESIGN

Retrospective cohort.

SETTING

National Medicare data.

PARTICIPANTS

Elderly Medicare beneficiaries discharged alive from an acute myocardial infarction (AMI) hospitalization in 2007-2008 (N = 184,156).

MEASUREMENTS

Study outcomes were number of guideline-recommended secondary prevention medications (statins, beta-blockers, and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers) used after discharge and 12-month survival. Preadmission data (FRIs, cardiovascular conditions, comorbid conditions), type of AMI (non-ST-elevation myocardial infarction, anterior, other), and procedures and complications during the hospitalization were from claims data.

RESULTS

Function-related indicators (FRIs) were common before admission; 50% of individuals had at least one (range 0-11). After discharge, 85.8% used at least one class of guideline medication, and 30.2% used all three; 19.6% died within 12 months. Each additional FRI reduced the likelihood of receiving all three medication classes by 5% (adjusted odds ratio = 0.95, 95% confidence interval (CI) = 0.94-0.96) and increased 12-month mortality by 20% (adjusted hazard ratio (aHR) = 1.20, 95% CI = 1.19-1.21). Individuals taking all three classes of medication were 30% less likely to die within 12 months than those not taking guideline medications (aHR = 0.70, 95% CI = 0.67-0.73). Similar survival benefit was observed in individuals with and without functional impairments.

CONCLUSION

Greater impairment in preadmission functional status, using a measure derived from claims data, was associated with less use of secondary prevention medications after AMI. Survival benefits of taking these medications were consistent across functional impairment levels.

Geographic variation in the use of adjuvant therapy among elderly patients with resected non-small cell lung cancer

OBJECTIVES

The purpose of this study was to assess to what extent geographic variation in adjuvant treatment for non-small cell lung cancer (NSCLC) patients would remain, after controlling for patient and area-level characteristics.

MATERIALS AND METHODS

A retrospective cohort of 18,410 Medicare beneficiaries with resected, stage I-IIIA NSCLC was identified from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. Adjuvant therapies were classified as adjuvant chemotherapy (ACT), postoperative radiation therapy (PORT), or no adjuvant therapy. Predicted treatment probabilities were estimated for each patient given their clinical, demographic, and area-level characteristics with multivariate logistic regression. Area Treatment Ratios were used to estimate the propensity of patients in a local area to receive an adjuvant treatment, controlling for characteristics of patients in the area. Areas were categorized as low-, mid- and high-use and mapped for two representative SEER registries.

RESULTS

Overall, 10%, 12%, and 78% of patients received ACT, PORT and no adjuvant therapy, respectively. Age, sex, stage, type and year of surgery, and comorbidity were associated with adjuvant treatment use. Even after adjusting for patient characteristics, substantial geographic treatment variation remained. High- and low-use areas were tightly juxtaposed within and across SEER registries, often within the same county. In some local areas, patients were up to eight times more likely to receive adjuvant therapy than expected, given their characteristics. On the other hand, almost a quarter of patients lived in local areas in which patients were more than three times less likely to receive ACT than would be predicted.

CONCLUSION

Controlling for patient and area-level covariates did not remove geographic variation in adjuvant therapies for resected NSCLC patients. A greater proportion of patients were treated less than expected, rather than more than expected. Further research is needed to better understand its causes and potential impact on outcomes.

Treatment Effect Estimation Using Nonlinear Two-Stage Instrumental Variable Estimators: Another Cautionary Note

OBJECTIVE

To examine the settings of simulation evidence supporting use of nonlinear two-stage residual inclusion (2SRI) instrumental variable (IV) methods for estimating average treatment effects (ATE) using observational data and investigate potential bias of 2SRI across alternative scenarios of essential heterogeneity and uniqueness of marginal patients.

STUDY DESIGN

Potential bias of linear and nonlinear IV methods for ATE and local average treatment effects (LATE) is assessed using simulation models with a binary outcome and binary endogenous treatment across settings varying by the relationship between treatment effectiveness and treatment choice.

PRINCIPAL FINDINGS

Results show that nonlinear 2SRI models produce estimates of ATE and LATE that are substantially biased when the relationships between treatment and outcome for marginal patients are unique from relationships for the full population. Bias of linear IV estimates for LATE was low across all scenarios.

CONCLUSIONS

Researchers are increasingly opting for nonlinear 2SRI to estimate treatment effects in models with binary and otherwise inherently nonlinear dependent variables, believing that it produces generally unbiased and consistent estimates. This research shows that positive properties of nonlinear 2SRI rely on assumptions about the relationships between treatment effect heterogeneity and choice.

Effect of hospitalization on inappropriate prescribing in elderly Medicare beneficiaries

OBJECTIVES

To determine whether acute hospitalization is associated with a change in potentially inappropriate medication (PIM) use and whether use varies across geographic region.

DESIGN

Observational.

SETTING

Continental United States.

PARTICIPANTS

Medicare beneficiaries aged 65 and older hospitalized for acute myocardial infarction (AMI) during 2007-08.

MEASUREMENTS

Potentially inappropriate medication use was defined according to the High-Risk Medications in Elderly Adults quality indicator from the Healthcare Effectiveness Data and Information Set. Prevalence of outpatient PIM use was determined at admission and discharge and then used to identify medications discontinued during hospitalization and incident medications started during this period.

RESULTS

Of 124,051 older adults hospitalized for AMI, 9,607 (7.7%) were outpatient PIM users at admission, which increased to 8.6% at discharge (P < .001). Admission PIM rates varied according to geographic region, as did the effect of hospitalization. Admission PIM use was lowest in the northeast and remained unchanged during hospitalization (5.1-5.1%, P = .95). In contrast, admission PIM use was highest in the south and increased significantly during hospitalization (9.9-11.4%, P < .001). PIM use also increased from the long-term perspective, with 6-month period prevalence rates of 22.6% before admission and 24.6% after discharge (P < .001).

CONCLUSION

Despite intervention studies demonstrating up to 80% reduction in PIM use during acute hospitalization, a significant increase in PIM use was observed in a naturalistic setting in Medicare beneficiaries with AMI. Further research is needed to develop an approach to minimizing PIM use in the inpatient setting that is cost-effective and suitable for widespread implementation.

Increased statin prescribing does not lower pneumonia risk

BACKGROUND

Investigators have attributed protective effects of statins against pneumonia and other infections. However, these reports are based on observational data where treatments are not assigned randomly. We aimed to determine if the protective effects of statins against pneumonia are due to nonrandom treatment assignment.

METHODS

We built a cohort consisting of 124 695 Medicare beneficiaries diagnosed with an acute myocardial infarction (AMI) for which we had complete claims data. We considered patients who survived at least 30 days post-AMI (full sample), or who survived for 1 year post-AMI (survivors). First, we used ordinary least squares (OLS) and logit models to determine if receiving a statin was protective against pneumonia. Second, to control for nonrandom treatment assignment, we performed an instrumental variables analysis using geographic treatment rates as an instrument. All models included patient demographics, medications, diagnoses, length of hospital stay, and out-of-pocket drug costs as covariates. Our outcome measure was a pneumonia diagnosis during the 1 year following AMI.

RESULTS

A total of 76 994 patients (61.9%) filled a statin prescription, and 19 078 (15.3%) were diagnosed with pneumonia. Using OLS, the statin coefficient was -0.016 (P < .001), indicating that statins are associated with a reduction in pneumonia. Using instrumental variables, we find that statin prescriptions are not associated with a reduction in pneumonia. For the full sample, statin coefficients ranged from -0.001 to -0.01 (P > .6).

CONCLUSIONS

For patients with AMI, the protective effect of statins against pneumonia is most likely the result of nonrandom treatment assignment (ie, a healthy-user bias).

Use of statins by medicare beneficiaries post myocardial infarction: poor physician quality or patient-centered care?

Even though guidelines strongly recommend that patients receive a statin for secondary prevention after an acute myocardial infarction (MI), many elderly patients do not fill a statin prescription within 30 days of discharge. This paper assesses whether patterns of statin use by Medicare beneficiaries post-discharge may be due to a mix of high-quality and low-quality physicians. Our data come from the Centers for Medicare & Medicaid Services (CMS) Chronic Condition Data Warehouse (CCW) and include 100% of Medicare beneficiaries hospitalized for an acute myocardial infarction in 2008 or 2009. Our study sample included physicians treating at least 10 Medicare fee-for-service beneficiaries during their MI institutional stay. Physician-specific statin fill rates (the proportion of each physician’s patients with a statin within 30 days post-discharge) were calculated to assess physician quality. We hypothesized that if the observed statin rates reflected a mix of high-quality and low-quality physicians, then physician-specific statin fill rates should follow a u-shaped or bimodal distribution. In our sample, 62% of patients filled a statin prescription within 30 days of discharge. We found that the distribution of statin fill rates across physicians was normal, with no clear distinctions in physician quality. Physicians, especially cardiologists, with relatively younger and healthier patient populations had higher rates of statin use. Our results suggest that physicians were engaging in patient-centered care, tailoring treatments to patient characteristics.

Cell-specific and developmental expression of lectican-cleaving proteases in mouse hippocampus and neocortex

Mounting evidence has demonstrated that a specialized extracellular matrix exists in the mammalian brain and that this glycoprotein-rich matrix contributes to many aspects of brain development and function. The most prominent supramolecular assemblies of these extracellular matrix glycoproteins are perineuronal nets, specialized lattice-like structures that surround the cell bodies and proximal neurites of select classes of interneurons. Perineuronal nets are composed of lecticans, a family of chondroitin sulfate proteoglycans that includes aggrecan, brevican, neurocan, and versican. These lattice-like structures emerge late in postnatal brain development, coinciding with the ending of critical periods of brain development. Despite our knowledge of the presence of lecticans in perineuronal nets and their importance in regulating synaptic plasticity, we know little about the development or distribution of the extracellular proteases that are responsible for their cleavage and turnover. A subset of a large family of extracellular proteases (called a disintegrin and metalloproteinase with thrombospondin motifs [ADAMTS]) is responsible for endogenously cleaving lecticans. We therefore explored the expression pattern of two aggrecan-degrading ADAMTS family members, ADAMTS15 and ADAMTS4, in the hippocampus and neocortex. Here, we show that both lectican-degrading metalloproteases are present in these brain regions and that each exhibits a distinct temporal and spatial expression pattern. Adamts15 mRNA is expressed exclusively by parvalbumin-expressing interneurons during synaptogenesis, whereas Adamts4 mRNA is exclusively generated by telencephalic oligodendrocytes during myelination. Thus, ADAMTS15 and ADAMTS4 not only exhibit unique cellular expression patterns but their developmental upregulation by these cell types coincides with critical aspects of neural development.

Effect of a care transition intervention by pharmacists: an RCT

Background

Pharmacists may improve medication-related outcomes during transitions of care. The aim of the Iowa Continuity of Care Study was to determine if a pharmacist case manager (PCM) providing a faxed discharge medication care plan from a tertiary care institution to primary care could improve medication appropriateness and reduce adverse events, rehospitalization and emergency department visits.

Methods

Design. Randomized, controlled trial of 945 participants assigned to enhanced, minimal and usual care groups conducted 2007 to 2012. Subjects. Participants with cardiovascular-related conditions and/or asthma or chronic obstructive pulmonary disease were recruited from the University of Iowa Hospital and Clinics following admission to general medicine, family medicine, cardiology or orthopedics. Intervention. The minimal group received admission history, medication reconciliation, patient education, discharge medication list and medication recommendations to inpatient team. The enhanced group also received a faxed medication care plan to their community physician and pharmacy and telephone call 3–5 days post-discharge. Participants were followed for 90 days post-discharge. Main Outcomes and Measures. Medication appropriateness index (MAI), adverse events, adverse drug events and post-discharge healthcare utilization were compared by study group using linear and logistic regression, as models accommodating random effects due to pharmacists indicated little clustering.

Results

Study groups were similar at baseline and the intervention fidelity was high. There were no statistically significant differences by study group in medication appropriateness, adverse events or adverse drug events at discharge, 30-day and 90-day post-discharge. The average MAI per medication as 0.53 at discharge and increased to 0.75 at 90 days, and this was true across all study groups. Post-discharge, about 16% of all participants experienced an adverse event, and this did not differ by study group (p > 0.05). Almost one-third of all participants had any type of healthcare utilization within 30 days post-discharge, where 15% of all participants had a 30-day readmission. Healthcare utilization post-discharge was not statistically significant different at 30 or 90 days by study group.

Conclusion

The pharmacist case manager did not affect medication use outcomes post-discharge perhaps because quality of care measures were high in all study groups.

Trial registration

Clinicaltrials.gov registration: NCT00513903, August 7, 2007.

Instrumental variable methods to assess quality of care the marginal effects of process-of-care on blood pressure change and treatment costs

BACKGROUND

Hypertension is poorly controlled. Team-based care and changes in the process of care have been proposed to address these quality problems. However, assessing care processes is difficult because they are often confounded even in randomized behavioral studies by unmeasured confounders based on discretion of health care providers.

OBJECTIVE

To evaluate the effects of process measures including number of counseling sessions about lifestyle modification and number of antihypertensive medications on blood pressure change and payer-perspective treatment costs.

METHODS

Data were obtained from two prospective, cluster randomized controlled clinical trials (Trial A and B) implementing physician-pharmacist collaborative interventions compared with usual care over six months in community-based medical offices in the Midwest. Multivariate linear regression models with both instrumental variable methods and as-treated methods were utilized. Instruments were indicators for trial and study arms. Models of blood pressure change and costs included both process measures, demographic variables, and clinical variables.

RESULTS

The analysis included 496 subjects. As-treated methods showed no significant associations between process and outcomes. The instruments used in the study were insufficient to simultaneously identify distinct process effects. However, the post-hoc instrumental variable models including one process measure at a time while controlling for the other process demonstrated significant associations between the processes and outcomes with estimates considerably larger than as-treated estimates.

CONCLUSIONS

Instrumental variable methods with combined randomized behavioral studies may be useful to evaluate the effects of different care processes. However, substantial distinct process variation across studies is needed to fully capitalize on this approach. Instrumental variable methods focusing on individual processes provided larger and stronger outcome relationships than those found using as-treated methods which are subject to confounding.

Treatment of diffuse large B-cell lymphoma in the elderly: regimens without anthracyclines are common and not futile

Anthracycline-containing regimens (ACRs) are recommended for patients with diffuse large B-cell lymphoma (DLBCL). However, over 40% of elderly patients do not receive ACRs, possibly due to expected toxicities. We characterized treatment choices and compared the 3-year overall survival (OS) rates of 8262 Medicare beneficiaries diagnosed with DLBCL in 2000-2006 identified from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database. Of the cohort, 45% had ACR with rituximab (ACR-R), 13% had ACR without R, 6% had non-ACR with R (non-ACR-R), 4% had R monotherapy, 3% had non-ACR and 29% had no systemic therapy. Patients not receiving ACR were older and/or had more comorbidities. The unadjusted OS was highest in ACR-R (65%), followed by ACR without R (55%) and non-ACR-R (44%). After adjusting patient covariates, ACR-R showed the best survival (63%). However, OS was comparable between non-ACR-R (52%) and ACR without R (52%). Non-ACR-R could be considered for patients who are poor candidates for ACR.

Accounting for unobservable exposure time bias when using Medicare prescription drug data

OBJECTIVE

To describe the prevalence and correlates of unobservable medication exposure time, and to recommend approaches for minimizing bias, in studies using Medicare Part D data..

SAMPLE

179,065 Medicare patients hospitalized for an AMI in 2007 or 2008.

METHODS

We compared two methods for creating medication exposure observation periods using acute care discharge vs. post-acute care discharge dates. We examined options for increasing cohort sizes by requiring different thresholds for observable days, or by using as a covariate, in the observation period. We calculated the extent and health status correlates of unobserved Medicare Part D exposure time and examined its association with receipt of beta-blockers.

RESULTS

39% of patients had unobservable time during the 30 day exposure assessment period following acute care; they were significantly older, had more comorbidity and longer acute care stays, had worse 1-year survival, and were significantly less likely to be classified as beta-blocker users. Using the alternative exposure assessment window, only 29% of the sample had unobservable time, and differences between groups were less pronounced. Significant gains in sample size can be obtained by restricting or controlling for the number of observable days required in the exposure assessment period.

CONCLUSIONS

Unobservable exposure time is common among Medicare Part D beneficiaries, and they are often in worse health. To retain patients with unobservable exposure time, we recommend stratifying patients on receipt of post-acute facility-based care, calculating and using observable days as a covariate and, when appropriate, using the discharge date from contiguous post-acute facility care for beginning the exposure assessment period.

What is the effect of area size when using local area practice style as an instrument?

OBJECTIVES

Discuss the tradeoffs inherent in choosing a local area size when using a measure of local area practice style as an instrument in instrumental variable estimation when assessing treatment effectiveness.

STUDY DESIGN

Assess the effectiveness of angiotensin converting-enzyme inhibitors and angiotensin receptor blockers on survival after acute myocardial infarction for Medicare beneficiaries using practice style instruments based on different-sized local areas around patients. We contrasted treatment effect estimates using different local area sizes in terms of the strength of the relationship between local area practice styles and individual patient treatment choices; and indirect assessments of the assumption violations.

RESULTS

Using smaller local areas to measure practice styles exploits more treatment variation and results in smaller standard errors. However, if treatment effects are heterogeneous, the use of smaller local areas may increase the risk that local practice style measures are dominated by differences in average treatment effectiveness across areas and bias results toward greater effectiveness.

CONCLUSION

Local area practice style measures can be useful instruments in instrumental variable analysis, but the use of smaller local area sizes to generate greater treatment variation may result in treatment effect estimates that are biased toward higher effectiveness. Assessment of whether ecological bias can be mitigated by changing local area size requires the use of outside data sources.

Standardizing Medicare payment information to support examining geographic variation in costs

OBJECTIVES

Examination of efficiency in health care requires that cost information be normalized. Medicare payments include both geographic and policy-based facility type differentials (e.g., wage index and disproportionate share hospital), which can bias cost comparisons of hospitals and averages across geographic areas. Standardizing payment information to remove the area- and policy-based payment differentials should normalize much of the observed geographic variability in payments, allowing for a more accurate comparison of resource use between providers and across geographic regions. Use of standardized payments will ensure that observed payment variation is due to differences in practice patterns and service use, rather than Medicare payment differences over which the providers have no control. This paper describes a method for standardizing claim payments, and demonstrates the difference in actual versus standardized payments by geographic region.

STUDY DESIGN AND METHODS

We used a nationwide cohort of Medicare patients hospitalized with an acute myocardial infarction (AMI) in 2007, then limited our study to those with Medicare Part A and Part B fee-for-service (FFS), and Part D coverage (n = 143,123). Standardized payment amounts were calculated for each Part A and Part B claim; standardized and actual payments were summed for all services for each patient beginning with the index hospitalization through 12 months post discharge.

PRINCIPAL FINDINGS

Without standardization of payments, certain areas of the country are mischaracterized as either high or low healthcare resource-consuming areas. The difference between actual and standardized payments varies by care setting.

CONCLUSIONS

Standardized payment amounts should be calculated when comparing Medicare resource use across geographic areas.

Incremental costs associated with physician and pharmacist collaboration to improve blood pressure control

STUDY OBJECTIVE

To compare costs associated with a physician-pharmacist collaborative intervention with costs of usual care.

DESIGN

Cost analysis using health care utilization and outcome data from two prospective, cluster-randomized, controlled clinical trials.

SETTING

Eleven community-based medical offices.

PATIENTS

A total of 496 patients with hypertension; 244 were in the usual care (control) group and 252 were in the intervention group.

MEASUREMENTS AND MAIN RESULTS

To compare the costs, we combined cost data from the two trials. Total costs included costs of provider time, laboratory tests, and antihypertensive drugs. Provider time was calculated based on an online survey of intervention pharmacists and the National Ambulatory Medical Care Survey. Cost parameters were taken from the Bureau of Labor Statistics for average wage rates, the Medicare laboratory fee schedule, and a publicly available Web site for drug prices. Total costs were adjusted for patient characteristics. Adjusted total costs were $774.90 in the intervention group and $445.75 in the control group (difference $329.16, p<0.001). In a sensitivity analysis, the difference in adjusted total costs between the two groups ranged from $224.27-515.56. The intervention cost required to have one additional patient achieve blood pressure control within 6 months was $1338.05, determined by the difference in costs divided by the difference in hypertension control rates between the groups ($329.16/24.6%). The cost over 6 months to lower systolic and diastolic blood pressure 1 mm Hg was $36.25 and $94.32, respectively.

CONCLUSION

The physician-pharmacist collaborative intervention increased not only blood pressure control but also the cost of care. Additional research, such as a cost-benefit or a cost-minimization analysis, is needed to assess whether financial savings related to reduced morbidity and mortality achieved from better blood pressure control outweigh the cost of the intervention.

Squeezing the balloon: propensity scores and unmeasured covariate balance

OBJECTIVE

To assess the covariate balancing properties of propensity score-based algorithms in which covariates affecting treatment choice are both measured and unmeasured.

DATA SOURCES/STUDY SETTING

A simulation model of treatment choice and outcome.

STUDY DESIGN

Simulation.

DATA COLLECTION/EXTRACTION METHODS

Eight simulation scenarios varied with the values placed on measured and unmeasured covariates and the strength of the relationships between the measured and unmeasured covariates. The balance of both measured and unmeasured covariates was compared across patients either grouped or reweighted by propensity scores methods.

PRINCIPAL FINDINGS

Propensity score algorithms require unmeasured covariate variation that is unrelated to measured covariates, and they exacerbate the imbalance in this variation between treated and untreated patients relative to the full unweighted sample.

CONCLUSIONS

The balance of measured covariates between treated and untreated patients has opposite implications for unmeasured covariates in randomized and observational studies. Measured covariate balance between treated and untreated patients in randomized studies reinforces the notion that all covariates are balanced. In contrast, forced balance of measured covariates using propensity score methods in observational studies exacerbates the imbalance in the independent portion of the variation in the unmeasured covariates, which can be likened to squeezing a balloon. If the unmeasured covariates affecting treatment choice are confounders, propensity score methods can exacerbate the bias in treatment effect estimates.

Estimating incremental costs with skew: a cautionary note

BACKGROUND

Cost data in healthcare are often skewed across patients. Thus, researchers have used either a log transformation of the dependent variable or generalized linear models with log links. However, frequently these non-linear approaches produce non-linear incremental effects: the incremental effects differ at different levels of the covariates, and this can cause dramatic effects on predicted cost.

OBJECTIVES

The aim of this study was to demonstrate that when modelling skewed data, log link functions or log transformations are not necessary and have unintended effects.

METHODS

We simulated cost data using a linear model with a 'treatment', a covariate and a specified number of observations with excessive cost (skewed data). We also used actual data from a pain-relief intervention among hip-replacement patients. We then estimated cost models using various functional approaches suggested to handle skew and calculated the incremental cost of treatment at various levels of the covariate(s).

RESULTS

All of these methods provide unbiased estimates of the incremental effect of treatment on costs at the mean level of the covariate. However, in some log-based models the implied incremental treatment cost doubled between extreme low and high values of the covariate in a manner inconsistent with the underlying linear model.

CONCLUSIONS

Although specification checks are always needed, the potential for misleading incremental estimates resulting from log-based specifications is often ignored. In this era of cost containment and comparisons of treatment effectiveness it is vital that researchers and policymakers understand the limitation of the inferences that can be made using log-based models for patients whose characteristics differ from the sample mean.

Comparison of instrumental variable analysis using a new instrument with risk adjustment methods to reduce confounding by indication

Confounding by indication is a vexing problem, especially in evaluating treatment effects using observational data, since treatment decisions are often related to disease severity, prognosis, and frailty. To compare the ability of the instrumental variable (IV) approach with a new instrument based on the local-area practice style and risk adjustment methods, including conventional multivariate regression and propensity score adjustment, to reduce confounding by indication, the authors investigated the effects of long-term control (LTC) therapy on the occurrence of acute asthma exacerbation events among children and young adults with incident and uncontrolled persistent asthma, using Iowa Medicaid claims files from 1997-1999. Established evidence from clinical trials has demonstrated the protective benefits of LTC therapy for persistent asthma. Among patients identified (n = 4,275), those with higher asthma severity at baseline were more likely to receive LTC therapy. The multivariate regression and propensity score adjustment methods suggested that LTC therapy had no effect on the occurrence of acute exacerbation events. Estimates from the new IV approach showed that LTC therapy significantly decreased the occurrence of acute exacerbation events, which is consistent with established clinical evidence. The authors discuss how to interpret estimates from the risk adjustment and IV methods when the treatment effect is heterogeneous.

Transfusion burden in non-dialysis chronic kidney disease patients with persistent anemia treated in routine clinical practice: a retrospective observational study

Background

Transfusion patterns are not well characterized in non-dialysis (ND) chronic kidney disease (CKD) patients. This study describes the proportion of patients transfused, units of blood transfused and trigger-hemoglobin (Hb) levels for transfusions in severe anemic, ND-CKD patients in routine practice.

Methods

A retrospective cohort study of electronic medical record data from the Henry Ford Health System identified 374 adult, ND-CKD patients with severe anemia (Hb < 10 g/dL and subsequent use of erythropoiesis-stimulating agents [ESA] therapy, blood transfusions, or a second Hb < 10 g/dL) between January 2004 and June 2008. Exclusions included those with prior diagnoses of cancer, renal or liver transplant, end-stage renal disease, acute bleeding, trauma, sickle cell disease, or aplastic anemia. A gap of ≥ 1 days between units of blood transfused was counted as a separate transfusion.

Results

At least 1 transfusion (mean of 2 units; range, 1-4) was administered to 20% (75/374) of ND-CKD patients with mean (± SD) follow-up of 459 (± 427) days. The mean (± SD) Hb level closest and prior to a transfusion was 8.8 (± 1.5) g/dL. Patients who were hospitalized in the 6 months prior to their first anemia diagnosis were 6.3 times more likely to receive a blood transfusion than patients who were not hospitalized (p < 0.0001). Patients with peripheral vascular disease (PVD) were twice as likely to have a transfusion as patients without PVD (p = 0.04).

Conclusions

Transfusions were prevalent and the trigger hemoglobin concentration was approximately 9 g/dL among ND-CKD patients with anemia. To reduce the transfusion burden, clinicians should consider other anemia treatments including ESA therapy.

Apples and oranges? Interpretations of risk adjustment and instrumental variable estimates of intended treatment effects using observational data

Instrumental variable (IV) and risk adjustment (RA) estimators, including propensity score adjustments, are both used to alleviate confounding problems in nonexperimental studies on treatment effects, but it is not clear how estimates based on these 2 approaches compare. Methodological considerations have shown that IV and RA estimators yield estimates of distinct types of causal treatment effects regardless of confounding problems. Many investigators have neglected these distinctions. In this paper, the authors use 3 schematic models to explain visually the relations between IV and RA estimates of intended treatment effects as demonstrated in the methodological studies. When treatment effects are homogeneous across a study population or when treatment effects are heterogeneous across the study population but treatment decisions are unrelated to the treatment effects, RA and IV estimates should be equivalent when the respective assumptions are met. In contrast, when treatment effects are heterogeneous and treatment decisions are related to the treatment effects, RA estimates of treatment effect can asymptotically differ from IV estimates, but both are correct even when the respective assumptions are met. Appropriate interpretations of IV or RA estimates can be facilitated by developing conceptual models related to treatment choice and treatment effect heterogeneity prior to analyses.

Outcomes following local therapy for early-stage breast cancer in non-trial populations

Recent studies suggest trends toward more mastectomies for primary breast cancer treatment. We assessed survival after mastectomy and breast-conserving surgery (BCS) with radiation for early-stage breast cancer among non-selected populations of women and among women similar to those in clinical trials. Using population-based data from Surveillance Epidemiology, and End Results cancer registries linked with Medicare administrative data from 1992 to 2005, we conducted propensity score analysis of survival following primary therapy for early-stage breast cancer, including BCS with radiation, BCS without radiation, mastectomy with radiation, and mastectomy without radiation. Adjusted survival was greatest among women who had BCS with radiation (median survival = 10.98 years). Compared with this group, mortality was higher among women who had mastectomy without radiation (median survival 10.04 years, adjusted hazard ratio (HR) = 1.19, 95% confidence interval (CI) = 1.14-1.23), mastectomy with radiation (median survival 10.02 years, HR = 1.20, 95% CI = 1.14-1.27), and BCS without radiation (median survival 7.63 years, HR = 1.81, 95% CI = 1.70-1.92). Among women representative of those eligible for clinical trials (age ≤70 years, Charlson comorbidity score = 0/1, and stage 1 tumors), there were no differences in survival for women who underwent BCS with radiation or mastectomy. In conclusion, after careful adjustment for differences in patient, physician, and hospital characteristics, we found better survival for BCS with radiation versus mastectomy among older early-stage breast cancer patients, with no difference in survival for BCS with radiation versus mastectomy among women representative of those in clinical trials. These findings are reassuring in light of recent trends towards more aggressive primary breast cancer therapy.

Effects of health savings account-eligible plans on utilization and expenditures

OBJECTIVE

To assess the impact of a health savings account (HSA)-eligible plan on utilization and expenditures in an employer-sponsored Midwestern health plan which offered a traditional plan from 2003 through 2004 that was fully replaced by an HSA-eligible plan in 2005 and 2006.

STUDY DESIGN

Retrospective pre-post design with a control group.

METHODS

Medical and pharmacy claims of plan members younger than 65 years who were continuously enrolled throughout the 4-year study period were used to evaluate the impact of switching to the HSA-eligible plan. Expenditure and utilization measures were compared with those for a control group covered by employers in the same industry and geographic location, while controlling for patient characteristics.

RESULTS

The HSA-eligible plan was associated with significantly lower total expenditures (-17.4%), fewer and less costly office visits (-13.6% and -20.3%, respectively), fewer emergency department (ED) visits (-20.1%), lower pharmacy expenditures (-29.2%), lower expenses per drug (-27.9%), a reduced likelihood of mammograms (odds ratio [OR] = 0.55, P <.05) and Papanicolaou tests (OR = 0.66, P <.05), and a borderline significant reduction in routine physical exams (OR = 0.76, P <.10). The HSA-eligible plan also was associated with increased outpatient facility expenditures (5.1%, P <.05).

CONCLUSION

Employer-sponsored HSA-eligible plans appear to be associated with lower healthcare expenditures and/or utilization, particularly for office visits, ED visits, and pharmacy. However, they also may discourage preventive care, leading to increased long-term medical costs. Employers offering HSA-eligible plans should ensure that there are no financial barriers for preventive services.

A methanotrophic marine molluscan (bivalvia, mytilidae) symbiosis: mussels fueled by gas

An undescribed mussel (family Mytilidae), which lives in the vicinity of hydrocarbon seeps in the Gulf of Mexico, consumes methane (the principal component of natural gas) at a high rate. The methane consumption is limited to the gills of these animals and is apparently due to the abundant intracellular bacteria found there. This demonstrates a methane-based symbiosis between an animal and intracellular bacteria. Methane consumption is dependent on the availability of oxygen and is inhibited by acetylene. The consumption of methane by these mussels is associated with a dramatic increase in oxygen consumption and carbon dioxide production. As the methane consumption of the bivalve can exceed its carbon dioxide production, the symbiosis may be able to entirely satisfy its carbon needs from methane uptake. The very light (delta(13)C = -51 to -57 per mil) stable carbon isotope ratios found in this animal support methane (delta(13)C = -45 per mil at this site) as the primary carbon source for both the mussels and their symbionts.