Comparative effectiveness of Denosumab vs alendronate among postmenopausal women with osteoporosis

Although clinical trials have shown that denosumab significantly increases bone mineral density at key skeletal sites more than oral bisphosphonates, evidence is lacking from head-to-head randomized trials evaluating fracture outcomes. This retrospective cohort study uses administrative claims data from Medicare fee-for service beneficiaries to evaluate the comparative effectiveness of denosumab versus alendronate in reducing fracture risk among women with postmenopausal osteoporosis (PMO) in the US. Women with PMO ≥ 66 years of age with no prior history of osteoporosis treatment, who initiated denosumab (n = 89 115) or alendronate (n = 389 536) from 2012 to 2018, were followed from treatment initiation until the first of a specific fracture outcome, treatment discontinuation or switch, end of study (December 31, 2019), or other censoring criteria. A doubly robust inverse-probability of treatment and censoring weighted function was used to estimate the risk ratio associated with the use of denosumab compared with alendronate for hip, nonvertebral (NV; includes hip, humerus, pelvis, radius/ulna, other femur), non-hip nonvertebral (NHNV), hospitalized vertebral (HV), and major osteoporotic (MOP; consisting of NV and HV) fractures. Overall, denosumab reduced the risk of MOP by 39%, hip by 36%, NV by 43%, NHNV by 50%, and HV fractures by 30% compared with alendronate. Denosumab reduced the risk of MOP fractures by 9% at year 1, 12% at year 2, 18% at year 3, and 31% at year 5. An increase in the magnitude of fracture risk reduction with increasing duration of exposure was also observed for other NV fracture outcomes. In this cohort of almost half-a-million treatment-naive women with PMO, we observed clinically significant reductions in the risk of MOP, hip, NV, NHNV, and HV fractures for patients on denosumab compared with alendronate. Patients who remained on denosumab for longer periods of time experienced greater reductions in fracture risk.

Influence of Incomplete Death Information on Cumulative Risk Estimates in United States Claims Data

Administrative claims databases often do not capture date or fact of death, so studies using these data may inappropriately treat death as a censoring event-equivalent to other withdrawal reasons-rather than a competing event. We examined 1-, 3-, and 5-year inverse-probability-of-treatment-weighted cumulative risks of a composite cardiovascular outcome among 34,527 initiators of telmisartan (exposure) and ramipril (referent) ages ≥55 in Optum claims from 2003 to 2020. Differences in cumulative risks of the cardiovascular endpoint due to censoring of death (cause-specific), as compared to treating death as a competing event (sub-distribution), increased with greater follow-up time and older age, where event and mortality risks were higher. Among ramipril users (selected results), 5-year cause-specific and sub-distribution cumulative risk estimates per 100, respectively, were 16.4 (95% CI 15.3, 17.5) and 16.2 (95% CI 15.1, 17.3) among ages 55-64 (difference=0.2) and were 43.2 (95% CI 41.3, 45.2) and 39.7 (95% CI 37.9, 41.4) among ages ≥75 (difference=3.6). Plasmode simulation results demonstrated the differences in cause-specific versus sub-distribution cumulative risks to increase with increasing mortality rate. We suggest researchers consider the cohort's baseline mortality risk when deciding whether real-world data with incomplete death information can be used without concern.

Staging and clean room: Constructs designed to facilitate transparency and reduce bias in comparative analyses of real-world data

PURPOSE

We describe constructs designed to protect the integrity of the results from comparative analyses using real-world data (RWD): staging and clean room.

METHODS

Staging involves performing sequential preliminary analyses and evaluating the population size available and potential bias before conducting comparative analyses. A clean room involves restricted access to data and preliminary results, policies governing exploratory analyses and protocol deviations, and audit trail. These constructs are intended to allow decisions about protocol deviations, such as changes to design or model specification, to be made without knowledge of how they might affect subsequent analyses. We describe an example for implementing staging with a clean room.

RESULTS

Stage 1 may involve selecting a data source, developing and registering a protocol, establishing a clean room, and applying inclusion/exclusion criteria. Stage 2 may involve attempting to achieve covariate balance, often through propensity score models. Stage 3 may involve evaluating the presence of residual confounding using negative control outcomes. After each stage, check points may be implemented when a team of statisticians, epidemiologists and clinicians masked to how their decisions may affect study outcomes, reviews the results. This review team may be tasked with making recommendations for protocol deviations to address study precision or bias. They may recommend proceeding to the next stage, conducting additional analyses to address bias, or terminating the study. Stage 4 may involve conducting the comparative analyses.

CONCLUSIONS

The staging and clean room constructs are intended to protect the integrity and enhance confidence in the results of analyses of RWD.

Global Epidemiology of Hip Fractures: Secular Trends in Incidence Rate, Post-Fracture Treatment, and All-Cause Mortality

In this international study, we examined the incidence of hip fractures, postfracture treatment, and all-cause mortality following hip fractures, based on demographics, geography, and calendar year. We used patient-level healthcare data from 19 countries and regions to identify patients aged 50 years and older hospitalized with a hip fracture from 2005 to 2018. The age- and sex-standardized incidence rates of hip fractures, post-hip fracture treatment (defined as the proportion of patients receiving anti-osteoporosis medication with various mechanisms of action [bisphosphonates, denosumab, raloxifene, strontium ranelate, or teriparatide] following a hip fracture), and the all-cause mortality rates after hip fractures were estimated using a standardized protocol and common data model. The number of hip fractures in 2050 was projected based on trends in the incidence and estimated future population demographics. In total, 4,115,046 hip fractures were identified from 20 databases. The reported age- and sex-standardized incidence rates of hip fractures ranged from 95.1 (95% confidence interval [CI] 94.8-95.4) in Brazil to 315.9 (95% CI 314.0-317.7) in Denmark per 100,000 population. Incidence rates decreased over the study period in most countries; however, the estimated total annual number of hip fractures nearly doubled from 2018 to 2050. Within 1 year following a hip fracture, post-hip fracture treatment ranged from 11.5% (95% CI 11.1% to 11.9%) in Germany to 50.3% (95% CI 50.0% to 50.7%) in the United Kingdom, and all-cause mortality rates ranged from 14.4% (95% CI 14.0% to 14.8%) in Singapore to 28.3% (95% CI 28.0% to 28.6%) in the United Kingdom. Males had lower use of anti-osteoporosis medication than females, higher rates of all-cause mortality, and a larger increase in the projected number of hip fractures by 2050. Substantial variations exist in the global epidemiology of hip fractures and postfracture outcomes. Our findings inform possible actions to reduce the projected public health burden of osteoporotic fractures among the aging population. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Comparability of Osteoporosis Treatment Groups Among Female Medicare Beneficiaries in the United States

It is often difficult to obtain valid estimates of comparative treatment effectiveness and safety owing to differences across patient populations taking different medications in the real world. One approach for assessing comparability between treatment groups in effectiveness studies is to use negative control outcomes (NCOs). NCOs share similar sources of bias with the primary outcomes but have no plausible causal relationship to the treatment of interest. Observing differences in the risk of NCOs thus provides evidence for residual confounding between groups. This retrospective study assessed the comparability of postmenopausal women, treated with osteoporosis medications with various mechanisms of action such as denosumab (RANKL inhibitor), zoledronic acid (bisphosphonate derivative), or oral bisphosphonates including alendronate. Administrative claims data were extracted from the US Centers for Medicare and Medicaid Services' Chronic Condition Warehouse database (May 2010 - December 2016). Propensity scores were used to match denosumab patients 1:1 to comparators. Four non-fracture NCOs and three early fracture NCOs (before substantial biologic effects of treatment would be expected) were assessed over 1-year and 3-month follow-up periods, respectively. According to comparability decision rules established a priori, patients initiating denosumab were comparable to those initiating zoledronic acid or alendronate, irrespective of prior osteoporosis treatment experience. Among new users, new switchers, and in the historical fracture subgroup, no meaningful differences were observed in the cumulative incidence of the 7 NCOs comparing denosumab to zoledronic acid. This empirical examination can assist in the selection of appropriate comparator groups for future comparability research using real-world data. This article is protected by copyright. All rights reserved.

Pragmatic considerations for negative control outcome studies to guide non-randomized comparative analyses: A narrative review

This narrative review describes the application of negative control outcome (NCO) methods to assess potential bias due to unmeasured or mismeasured confounders in non-randomized comparisons of drug effectiveness and safety. An NCO is assumed to have no causal relationship with a treatment under study while subject to the same confounding structure as the treatment and outcome of interest; an association between treatment and NCO then reflects the potential for uncontrolled confounding between treatment and outcome. We focus on two recently completed NCO studies that assessed the comparability of outcome risk for patients initiating different osteoporosis medications and lipid-lowering therapies, illustrating several ways in which confounding may result. In these studies, NCO methods were implemented in claims-based data sources, with the results used to guide the decision to proceed with comparative effectiveness or safety analyses. Based on this research, we provide recommendations for future NCO studies, including considerations for the identification of confounding mechanisms in the target patient population, the selection of NCOs expected to satisfy required assumptions, the interpretation of NCO effect estimates, and the mitigation of uncontrolled confounding detected in NCO analyses. We propose the use of NCO studies prior to initiating comparative effectiveness or safety research, providing information on the potential presence of uncontrolled confounding in those comparative analyses. Given the increasing use of non-randomized designs for regulatory decision-making, the application of NCO methods will strengthen study design, analysis, and interpretation of real-world data and the credibility of the resulting real-world evidence. This article is protected by copyright. All rights reserved.

Changes in Medication Use During Pregnancy for Women with Chronic Conditions: An Analysis of Claims Data

PURPOSE

Evaluation of drug safety during pregnancy is dependent on the number of exposed women during routine clinical practice with data available for analysis. We examined medication fills in pregnant and nonpregnant women within select disease cohorts: general population, migraine, diabetes, and hyperlipidemia to explore the potential use of claims data to assess medication use and safety during pregnancy.

METHODS

This cohort study, using IBM MarketScan® Research Databases claims data, included women 10-54 years of age with pregnancy resulting in a liveborn infant between January 2010 and September 2015 and matched nonpregnant women. Medication use (antidepressants, antihypertensives, sedatives, glucose-lowering medications, antiepileptics, antipsychotics, lipid-lowering medications) was abstracted from pharmacy claims 180 days before last menstrual period through 180 days postdelivery.

RESULTS

Among 753,760 women in the general pregnancy population (including 73,268 migraine, 50,155 hyperlipidemia, and 8361 diabetes; non-exclusive cohorts), antidepressants, antihypertensives, and sedatives were the most commonly used medications during pregnancy. Medications of interest were less commonly used in the pregnancy cohort than in the matched nonpregnant cohort within each time period (e.g., 3.7% vs 13.1% antidepressant use in 1st trimester). Most prescription fills were less common during pregnancy then pre-pregnancy. Post-pregnancy, prescription fills increased to or exceeded pre-pregnancy levels, except antihypertensive and glucose-lowering medications, which increased during pregnancy.

CONCLUSIONS

Medication use among pregnant women was low and different from that among matched nonpregnant women. The underlying size of large commercial claims databases offer opportunities for efficient evaluation of potential safety concerns, particularly for rare drug exposures, compared to traditional pregnancy registries.

External Comparator Groups Derived from Real-world Data Used in Support of Regulatory Decision Making: Use Cases and Challenges

Real-world data (RWD) from electronic health records (EHRs) and administrative claims databases are used increasingly to generate real-world evidence (RWE). RWE is used to support clinical evidence packages for medicines that inform decision-makers. In this review of current issues in the use of RWD-derived external comparator groups to support regulatory filings, we assess a series of topics that generally apply across many disease indications. However, most of the examples and illustrations focus on the oncology clinical research setting. The topics include an overview of current uses of RWD in drug development, a discussion of regulatory filings using RWD-derived external comparators, a brief overview of guidance documents and white papers pertaining to external comparators, a summary of some limitations and methodological issues in the use of external comparator groups and finally, a look at the future of this area and recommendations.

Trends in characteristics and outcomes among US adults hospitalised with COVID-19 throughout 2020: an observational cohort study

OBJECTIVES

To examine the temporal patterns of patient characteristics, treatments used and outcomes associated with COVID-19 in patients who were hospitalised for the disease between January and 15 November 2020.

DESIGN

Observational cohort study.

SETTING

COVID-19 subset of the Optum deidentified electronic health records, including more than 1.8 million patients from across the USA.

PARTICIPANTS

There were 51 510 hospitalised patients who met the COVID-19 definition, with 37 617 in the laboratory positive cohort and 13 893 in the clinical cohort.

PRIMARY AND SECONDARY OUTCOME MEASURES

Incident acute clinical outcomes, including in-hospital all-cause mortality.

RESULTS

Respectively, 48% and 49% of the laboratory positive and clinical cohorts were women. The 50- 65 age group was the median age group for both cohorts. The use of antivirals and dexamethasone increased over time, fivefold and twofold, respectively, while the use of hydroxychloroquine declined by 98%. Among adult patients in the laboratory positive cohort, absolute age/sex standardised incidence proportion for in-hospital death changed by -0.036 per month (95% CI -0.042 to -0.031) from March to June 2020, but remained fairly flat from June to November, 2020 (0.001 (95% CI -0.001 to 0.003), 17.5% (660 deaths /3986 persons) in March and 10.2% (580/5137) in October); in the clinical cohort, the corresponding changes were -0.024 (95% CI -0.032 to -0.015) and 0.011 (95% CI 0.007 0.014), respectively (14.8% (175/1252) in March, 15.3% (189/1203) in October). Declines in the cumulative incidence of most acute clinical outcomes were observed in the laboratory positive cohort, but not for the clinical cohort.

CONCLUSION

The incidence of adverse clinical outcomes remains high among COVID-19 patients with clinical diagnosis only. Patients with COVID-19 entering the hospital are at elevated risk of adverse outcomes.

Characteristics and outcomes of hospitalised adults with COVID-19 in a Global Health Research Network: a cohort study

OBJECTIVE

To examine age, gender, and temporal differences in baseline characteristics and clinical outcomes of adult patients hospitalised with COVID-19.

DESIGN

A cohort study using deidentified electronic medical records from a Global Research Network.

SETTING/PARTICIPANTS

67 456 adult patients hospitalised with COVID-19 from the USA; 7306 from Europe, Latin America and Asia-Pacific between February 2020 and January 2021.

RESULTS

In the US cohort, compared with patients 18-34 years old, patients ≥65 had a greater risk of intensive care unit (ICU) admission (adjusted HR (aHR) 1.73, 95% CI 1.58 to 1.90), acute respiratory distress syndrome(ARDS)/respiratory failure (aHR 1.86, 95% CI 1.76 to 1.96), invasive mechanical ventilation (IMV, aHR 1.93, 95% CI, 1.73 to 2.15), and all-cause mortality (aHR 5.6, 95% CI 4.36 to 7.18). Men appeared to be at a greater risk for ICU admission (aHR 1.34, 95% CI 1.29 to 1.39), ARDS/respiratory failure (aHR 1.24, 95% CI1.21 to 1.27), IMV (aHR 1.38, 95% CI 1.32 to 1.45), and all-cause mortality (aHR 1.16, 95% CI 1.08 to 1.24) compared with women. Moreover, we observed a greater risk of adverse outcomes during the early pandemic (ie, February-April 2020) compared with later periods. In the ex-US cohort, the age and gender trends were similar; for the temporal trend, the highest proportion of patients with all-cause mortality were also in February-April 2020; however, the highest percentages of patients with IMV and ARDS/respiratory failure were in August-October 2020 followed by February-April 2020.

CONCLUSIONS

This study provided valuable information on the temporal trends of characteristics and outcomes of hospitalised adult COVID-19 patients in both USA and ex-USA. It also described the population at a potentially greater risk for worse clinical outcomes by identifying the age and gender differences. Together, the information could inform the prevention and treatment strategies of COVID-19. Furthermore, it can be used to raise public awareness of COVID-19's impact on vulnerable populations.

Cinacalcet and gastrointestinal bleeding risk in patients receiving hemodialysis

PURPOSE

Secondary hyperparathyroidism (SHPT) is common among dialysis patients, and calcimimetics are a mainstay of treatment. This study assessed whether cinacalcet use is associated with gastrointestinal bleeding in a large hemodialysis cohort.

METHODS

A linked database of clinical records and medical claims for patients receiving hemodialysis in a large dialysis organization, 2007-2010, was used. A nested case-control study was performed among patients aged ≥18 years who had received hemodialysis for ≥90 days, had Medicare Parts A, B, and D coverage for ≥1 year, and had clinical evidence of SHPT (parathyroid hormone >300 pg/mL). Cases were those who experienced death or hospitalization caused by gastrointestinal bleeding. Each case was matched to up to four controls. Exposure was measured by any cinacalcet use, current use, past use, cumulative exposure days, and cumulative dosage. Conditional logistic models were used to assess the association.

RESULTS

Of 48 437 patients included, 2570 experienced gastrointestinal bleeding events (2498 non-fatal, 72 fatal), and 2465 (2397 non-fatal, 68 fatal) were matched to 9500 controls; 17.2% of cases and 15.8% of controls had cinacalcet exposure and 11.1% of both cases and controls had current use. The adjusted odds ratios (95% CI) of gastrointestinal bleeding for any use, current use, and past use of cinacalcet were 1.04 (0.91-1.19), 0.97 (0.83-1.13), and 1.22 (0.99-1.50), respectively, with no use as the reference.

CONCLUSION

The results do not suggest an elevated risk of gastrointestinal bleeding resulting in hospitalization or death for hemodialysis patients exposed to cinacalcet.

Combinations of mineral and bone disorder markers and risk of death and hospitalizations in the international Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Prior studies have developed a chronic kidney disease-mineral and bone disorder (CKD-MBD) composite score based on combinations of calcium (Ca), phosphorus (P) and parathyroid hormone (PTH) that have been shown to be associated with an increased risk of clinical outcomes in the USA. We examined this association in a contemporary, international cohort of hemodialysis patients.

METHODS

We studied 19 313 patients surviving ≥12 months in the Dialysis Outcomes and Practice Patterns Study Phases 3-5 (2005-15) from Europe, Canada and the USA. The CKD-MBD composite score was defined as the number of markers above target levels (P, 3.5-5.5 mg/dL; Ca, 8.4-10.2 mg/dL; PTH, 150-600 pg/mL). Using Cox models, we estimated hazard ratios (HRs) for death and a composite event (death or hospitalization), contrasting MBD 2/3 (2-3 parameters above target) with MBD 0 (all in target), adjusted for a disease risk score (DRS).

RESULTS

MBD 2/3 above target was observed in 10-14% of patients across regions and was associated with greater DRS-adjusted mortality {HR 1.41 [95% confidence interval (CI) 1.10-1.82]} and composite events [HR 1.23 (95% CI 1.10-1.38)] in the USA compared with MBD 0; the mortality association was stronger for patients ≥ 65 years of age [HR 1.82 (95% CI 1.28-2.58)] compared with patients <65 years of age [HR 1.11 (95% CI 0.80-1.55)]. HRs observed in Canada and Europe were generally consistent but weaker. Estimates for MBD 2/3 outside target (above or below) were slightly lower in all regions.

CONCLUSIONS

Simultaneous consideration of Ca, P and PTH may help in identifying patients on dialysis with a higher risk of major clinical outcomes related to CKD-MBD.

Duration of short-acting granulocyte colony-stimulating factor for primary prophylaxis and risk of neutropenia-related hospitalization in older patients with cancer

PURPOSE

Evaluate the relationship between duration of primary prophylactic short-acting granulocyte colony-stimulating factor (PP-sG-CSF) and risk of neutropenia-related hospitalization (NRH) in older patients receiving myelosuppressive chemotherapy.

METHODS

Using the Medicare claims database, we conducted a nested case-control study in a cohort of patients aged ≥66 years with breast, colorectal, lung, ovarian, or prostate cancer, or non-Hodgkin lymphoma who initiated a first cycle of any myelosuppressive chemotherapy January 1, 2008-September 30, 2016, and received PP-sG-CSF. We matched up to four controls to each NRH case by age, cancer type, regimen febrile neutropenia (FN) risk category, and year using incidence density sampling. We used conditional logistic regression adjusted for race, sex, and modified Charlson comorbidity index (CCI) to estimate relative risk of NRH related to duration of PP-sG-CSF categorized as <5 and ≥ 5 days.

RESULTS

Of 2148 patients receiving PP-sG-CSF, 108 (5%) experienced NRH in the first cycle. We matched 333 controls to 96 cases. Cases were similar to controls in mean age, tumor type, and intermediate/high-risk regimen, but were more likely to have CCI ≥5 and less likely to use PP-sG-CSF ≥5 days (31% vs. 39%). Adjusted ORs (95% CI) for NRH were 0.69 (0.40-1.19) for ≥5 vs. <5 days of PP-sG-CSF among patients receiving any myelosuppressive chemotherapy, 0.43 (0.21-0.89) for intermediate/high-risk regimen, and 0.42 (0.19-0.89) for any myelosuppressive chemotherapy with all agents given on cycle day one only.

CONCLUSIONS

Among older patients with cancer who are receiving PP-sG-CSF, ≥5 days of use was associated with substantial reduction in NRH risk.

Using negative control outcomes to assess the comparability of treatment groups among women with osteoporosis in the United States

PURPOSE

In contrast to randomized clinical trials, comparative safety and effectiveness assessments of osteoporosis medications in clinical practice may be subject to confounding by indication. We used negative control outcomes to detect residual confounding when comparing osteoporosis medications.

METHODS

Using MarketScan Commercial and Supplemental claims, we identified women aged ≥55 years who initiated an oral bisphosphonate (BP) (risedronate, alendronate, or ibandronate), denosumab (an injected biologic), or intravenous zoledronic acid (ZA) from October 1, 2010 to September 30, 2015. Women with Paget's disease or cancer were excluded. We compared individual oral BPs to each other, denosumab to ZA, denosumab to oral BPs, and ZA to oral BPs, with respect to 11 negative control outcomes identified by subject matter experts. We estimated the 12-month cumulative risk difference (RD) using inverse probability of treatment and censoring weights.

RESULTS

Among 148 587 women, most initiated alendronate (57%), followed by ibandronate (12%), ZA (11%), risedronate (10%), and denosumab (10%). Compared with denosumab, patients initiating ZA had similar risks of all negative control outcomes. Compared with oral BPs, patients initiating denosumab had a higher risk of a wellness visit (RD = 1.2%, 95% CI: 0.4, 1.9) and a lower risk of receiving herpes zoster vaccine (RD = -0.6%, 95% CI: -1.1, -0.2). Comparing ZA with oral BP initiators resulted in two outcomes with positive associations.

CONCLUSIONS

Caution is warranted when comparing injectable vs oral osteoporosis medications, given the potential for unmeasured confounding. Evaluating negative control outcomes could be a standard validity check prior to conducting comparative studies.

Patterns of granulocyte colony-stimulating factor prophylaxis in patients with cancer receiving myelosuppressive chemotherapy

Purpose

To evaluate patterns of primary prophylactic (PP) granulocyte colony–stimulating factor (G-CSF) use following chemotherapy by cancer type and febrile neutropenia (FN) risk.

Methods

Using a commercial administrative database, we identified adult patients diagnosed with breast, colorectal, lung, ovarian cancer, or non-Hodgkin lymphoma (NHL) who initiated chemotherapy with high risk (HR) or intermediate risk (IR) for FN between January 1, 2013, and August 31, 2017. We describe use of PP-G-CSF, proportion completing all their cycles with pegfilgrastim, timing of pegfilgrastim, and duration of short-acting G-CSF.

Results

Among 22,868 patients (breast 11,513; colorectal 3765; lung 4273; ovarian 1287; and NHL 2030), 36.8% received HR and 63.2% received IR (64.4% of whom had ≥ 1 risk factor [RF] for FN). Proportions of patients receiving PP-G-CSF in the first cycle were 76.1%, 28.2%, and 26.4% among patients receiving HR, IR, and IR plus ≥ 1 RF, respectively. Among breast cancer patients receiving HR regimens and initiating PP-pegfilgrastim, 60.4% (95% confidence interval [CI] 57.2–63.6%) initiating via on-body injector (OBI) and 51.9% (95% CI 48.0–55.8%) initiating via prefilled syringe (PFS) completed all their cycles with OBI and PFS, respectively. Among all cycles with PP-PFS, 8.5% received PFS on the same day as chemotherapy completion. Mean administrations/cycle were 3.2 (standard deviation [SD] 2.3) for filgrastim, 3.0 (SD 1.6) for filgrastim-sndz, and 4.3 (SD 2.5) for tbo-filgrastim.

Conclusions

There is under- and mistimed use of PP-G-CSF among patients at HR for FN. Novel pegfilgrastim delivery devices could help breast cancer patients at HR for FN complete all their cycles with timely prophylaxis.

Electronic supplementary material

The online version of this article (10.1007/s00520-020-05295-2) contains supplementary material, which is available to authorized users.

Association of hospital transfusion use and infection-related rehospitalizations among patients receiving hemodialysis: A retrospective cohort study

INTRODUCTION

Red blood cell transfusions have been associated with infection risk. We investigated whether hospital transfusions are associated with infections in maintenance hemodialysis patients requiring transfusions for chronic anemia.

METHODS

In this retrospective cohort study, hemodialysis patients who experienced an incident hospitalization during 2012-2013 were identified from the Medicare end-stage renal disease database. Hospital transfusions were first categorized into one of five groups based on adjusted likelihood of administering red blood cell transfusions during inpatient hospital stays that occurred over the previous year (2011) among the general Medicare cohort. Next, in a patient-level analysis, patients were categorized according to transfusion use at the incident hospitalization hospital. Outcomes were infection-related rehospitalization and a composite of infection-related hospitalization and all-cause mortality during the 60 days following hospital discharge. We estimated adjusted rate ratios for the association between hospital transfusion use and risk of rehospitalization or the composite endpoint using Poisson regression models.

FINDINGS

The study included 1578 hospitals and 61,455 hemodialysis patients. Patient characteristics were balanced across hospital transfusion use groups. The overall transfusion rate was 16.0%. The overall 30-day infection-related hospitalization rate (95% confidence interval) per 100 patient-months was 8.8 (8.6-9.1); rates did not differ by transfusion use group. Rate ratios for infection-related rehospitalization were 1.00 (0.91-1.10) over 30 days and 0.98 (0.91-1.05) over 60 days comparing the lowest and highest transfusion use groups.

DISCUSSION

We found no differences in risk of infection-related rehospitalization for patients receiving maintenance hemodialysis across the varying blood transfusion rates of US hospitals.

Methodologic considerations for noninterventional studies of switching from reference biologic to biosimilars

PURPOSE

As more biosimilars become available in the United States, postapproval noninterventional studies describing biosimilar switching and comparing effectiveness and/or safety between switchers and nonswitchers will play a key role in generating real-world evidence to inform clinical practices and policy decisions. Ensuring sound methodology is critical for making valid inferences from these studies.

METHODS

The Biologics and Biosimilars Collective Intelligence Consortium (BBCIC) convened a workgroup consisting of academic researchers, industry scientists, and practicing clinicians to establish best practice recommendations for the conduct of noninterventional studies of biosimilar and reference biologic switching. The workgroup members participated in eight teleconferences between August 2017 and February 2018 to discuss specific topics and build consensus.

RESULTS

This report provides workgroup recommendations covering five main considerations relating to noninterventional studies describing reference biologic to biosimilar switching and comparing reference biologic to biosimilars for safety and effectiveness in the presence of switching at treatment initiation and during follow-up: (a) selecting appropriate data sources from a range of available options including insurance claims, electronic health records, and registries; (b) study designs; (c) outcomes of interest including health care utilization and clinical endpoints; (d) analytic approaches including propensity scores, disease risk scores, and instrumental variables; and (e) special considerations including avoiding designs that ignore history of biologic use, avoiding immortal time bias, exposure misclassification, and accounting for postindex switching.

CONCLUSION

Recommendations provided in this report provide a framework that may be helpful in designing and critically evaluating postapproval noninterventional studies involving reference biologic to biosimilar switching.

Risk of neutropenia-related hospitalization (NRH) related to duration of short-acting granulocyte colony stimulating factor (sG-CSF) for primary prophylaxis

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Background: In clinical trials, efficacy of 10–11 days of primary prophylactic (PP) sG-CSF is similar to a single dose of pegfilgrastim for preventing febrile neutropenia (FN). However, most patients receive < 10 days of PP sG-CSF in clinical practice. This study assessed the effect of PP sG-CSF duration on the risk of NRH. Methods: Using Medicare 20% sample data, we conducted a nested case-control study within a cohort of patients aged ≥66 y with breast, colorectal, lung, ovarian, or prostate cancer or NHL who initiated first cycle of chemotherapy 1/1/2008–9/30/2016, had ≥1 y continuous coverage in Medicare parts A and B before cycle day 1 (baseline), and received PP sG-CSF. We identified NRH cases (ICD-9, 288.0X; ICD-10, D70.X) from cycle day 5 to end of cycle 1. We matched each case to up to 4 controls based on age (± 1 y), tumor type, regimen risk for FN (intermediate/high [ > 10%], other), and year using incidence density sampling. Duration of sG-CSF (days of use from cycle day 1 to the day before case date) was categorized as < 5 and ≥5 days. We used conditional logistic regression adjusted for race, sex, and Charlson comorbidity index (CCI) at baseline to estimate relative risk of NRH related to duration of sG-CSF. Results: Of 1431 patients receiving PP sG-CSF, 68 cases matched 231 controls. Cases were similar to controls in age (76 vs 75 y), tumor type (NHL, 62% vs 62%; lung cancer, 25% vs 25%), intermediate-/high-risk regimen (65% vs 67%), and male sex (50% vs 48%) but had slightly higher CCI (3.9 vs 3.3). The percentage of patients with ≥5 days of PP sG-CSF use was 26% in cases and 41% in controls. The adjusted OR (95% CI) for NRH was 0.48 (0.25–0.93) for ≥5 vs < 5 days of PP sG-CSF; results were consistent across sensitivity analyses (Table). Conclusions: Among elderly cancer patients receiving PP sG-CSF, ≥5 days of sG-CSF use was associated with substantial reduction in the risk of NRH.[Table: see text]

Excess Deaths Attributable to Influenza-Like Illness in the ESRD Population

BACKGROUND

Morbidity and mortality vary seasonally. Timing and severity of influenza seasons contribute to those patterns, especially among vulnerable populations such as patients with ESRD. However, the extent to which influenza-like illness (ILI), a syndrome comprising a range of potentially serious respiratory tract infections, contributes to mortality in patients with ESRD has not been quantified.

METHODS

We used data from the Centers for Disease Control and Prevention (CDC) Outpatient Influenza-like Illness Surveillance Network and Centers for Medicare and Medicaid Services ESRD death data from 2000 to 2013. After addressing the increasing trend in deaths due to the growing prevalent ESRD population, we calculated quarterly relative mortality compared with average third-quarter (summer) death counts. We used linear regression models to assess the relationship between ILI data and mortality, separately for quarters 4 and 1 for each influenza season, and model parameter estimates to predict seasonal mortality counts and calculate excess ILI-associated deaths.

RESULTS

An estimated 1% absolute increase in quarterly ILI was associated with a 1.5% increase in relative mortality for quarter 4 and a 2.0% increase for quarter 1. The average number of annual deaths potentially attributable to ILI was substantial, about 1100 deaths per year.

CONCLUSIONS

We found an association between community ILI activity and seasonal variation in all-cause mortality in patients with ESRD, with ILI likely contributing to >1000 deaths annually. Surveillance efforts, such as timely reporting to the CDC of ILI activity within dialysis units during influenza season, may help focus attention on high-risk periods for this vulnerable population.

Use of the Medicare database in epidemiologic and health services research: a valuable source of real-world evidence on the older and disabled populations in the US

Medicare is the federal health insurance program for individuals in the US who are aged ≥65 years, select individuals with disabilities aged <65 years, and individuals with end-stage renal disease. The Centers for Medicare and Medicaid Services grants researchers access to Medicare administrative claims databases for epidemiologic and health outcomes research. The data cover beneficiaries’ encounters with the health care system and receipt of therapeutic interventions, including medications, procedures, and services. Medicare data have been used to describe patterns of morbidity and mortality, describe burden of disease, compare effectiveness of pharmacologic therapies, examine cost of care, evaluate the effects of provider practices on the delivery of care and patient outcomes, and explore the health impacts of important Medicare policy changes. Considering that the vast majority of US citizens ≥65 years of age have Medicare insurance, analyses of Medicare data are now essential for understanding the provision of health care among older individuals in the US and are critical for providing real-world evidence to guide decision makers. This review is designed to provide researchers with a summary of Medicare data, including the types of data that are captured, and how they may be used in epidemiologic and health outcomes research. We highlight strengths, limitations, and key considerations when designing a study using Medicare data. Additionally, we illustrate the potential impact that Centers for Medicare and Medicaid Services policy changes may have on data collection, coding, and ultimately on findings derived from the data.

Facility-level CKD-MBD composite score and risk of adverse clinical outcomes among patients on hemodialysis

BACKGROUND

Patients receiving hemodialysis with values outside of target levels for parathyroid hormone (PTH: 150-600 pg/mL), calcium (Ca: 8.4-10.2 mg/dL), and phosphate (P: 3.5-5.5 mg/dL) are at elevated morbidity and mortality risk. We examined whether patients receiving care in dialysis facilities where greater proportions of patients have at least two values out of target have a higher risk of adverse clinical outcomes.

METHODS

The study cohort consisted of 39,085 prevalent hemodialysis patients in 1298 DaVita dialysis facilities as of September 1, 2009, followed from January 1, 2010, until an outcome, a censoring event, or December 31, 2010. We determined the quintile of the distribution across facilities of the proportion of patients with at least two of three parameters out of, or above, target over a 4-month baseline period. The primary composite outcome was cardiovascular hospitalization or death. Secondary outcomes included death, cardiovascular hospitalization, and parathyroidectomy. Poisson regression models were used to estimate the association of facility quintile with outcomes.

RESULTS

Facility quintile was associated with a 7 % increased risk of cardiovascular hospitalization or death (quintile 5 versus 1, RR 1.07, 95 % CI 1.01-1.13) using the out-of-target measure of exposure and a 12 % increased risk (RR 1.12, 95 % CI 1.06-1.19) using the above-target measure. No association was seen for death using either measure. Patients in facility quintiles 3-5 (versus 1) were at increased parathyroidectomy risk (RR ranged from 2.05, 95 % CI 1.10-3.82, for quintile 3 to 2.73, 95 % CI 1.50-4.98, for quintile 5).

CONCLUSIONS

Facility level analysis of a large prevalent sample of US patients on hemodialysis demonstrates that patients in facilities with the least control of PTH, Ca, and P had the greatest risk of parathyroidectomy or the combination of cardiovascular hospitalization or death.

The association between cinacalcet use and missed in-center hemodialysis treatment rate

PURPOSE

Missed in-center hemodialysis treatments (MHT) are a general indicator of health status in hemodialysis patients. This analysis was conducted to estimate the association between cinacalcet use and MHT rate.

METHODS

We studied patients receiving hemodialysis and prescription benefits services from a large dialysis organization. Incident cinacalcet users were propensity score matched to controls on 31 demographic, clinical, and laboratory variables. We applied inverse probability (IP) of censoring and crossover weights to account for informative censoring. Weighted negative binomial modeling was used to estimate MHT rates and pooled logistics models were used to estimate the association between cinacalcet use and MHT.

RESULTS

Baseline demographic and clinical variables included serum calcium, phosphorus, parathyroid hormone, and vitamin D use, and were balanced between 15,474 new cinacalcet users and 15,474 matched controls. In an analysis based on intention-to-treat principles, 40.8% of cinacalcet users and 46.5% of nonusers were censored. MHT rate was 13% lower among cinacalcet initiators versus controls: IP of censoring weighted incidence rate ratio was 0.87 (95% confidence interval [CI]: 0.84-0.90 p < 0.001). In analyses based on as-treated principles, 72.8% and 61.5% of cinacalcet users and nonusers, respectively, crossed over or were censored. MHT rate was 15% lower among cinacalcet initiators versus controls: IP of censoring/crossover weighted incidence rate ratio was 0.85 (95%CI: 0.82-0.87 p < 0.001).

CONCLUSIONS

After controlling for indication and differential censoring, cinacalcet treatment was associated with lower MHT rates, which may reflect better health status. Copyright © 2016 John Wiley & Sons, Ltd.

Epoetin Alfa and Outcomes in Dialysis amid Regulatory and Payment Reform

Erythropoiesis-stimulating agents (ESAs) are commonly used to treat anemia in patients with CKD, including those receiving dialysis, although clinical trials have identified risks associated with ESA use. We evaluated the effects of changes in dialysis payment policies and product labeling instituted in 2011 on mortality and major cardiovascular events across the United States dialysis population in an open cohort study of patients on dialysis from January 1, 2005, through December 31, 2012, with Medicare as primary payer. We compared observed rates of death and major cardiovascular events in 2011 and 2012 with expected rates calculated on the basis of rates in 2005-2010, accounting for differences in patient characteristics and influenza virulence. An abrupt decline in erythropoietin dosing and hemoglobin concentration began in late 2010. Observed rates of all-cause mortality, cardiovascular mortality, and myocardial infarction in 2011 and 2012 were consistent with expected rates. During 2012, observed rates of stroke, venous thromboembolic disease (VTE), and heart failure were lower than expected (absolute deviation from trend per 100 patient-years [95% confidence interval]: -0.24 [-0.08 to -0.37] for stroke, -2.43 [-1.35 to -3.70] for VTE, and -0.77 [-0.28 to -1.27] for heart failure), although non-ESA-related changes in practice and Medicare payment penalties for rehospitalization may have confounded the results. This initial evidence suggests that action taken to mitigate risks associated with ESA use and changes in payment policy did not result in a relative increase in death or major cardiovascular events and may reflect improvements in stroke, VTE, and heart failure.

Geovariation in Fracture Risk among Patients Receiving Hemodialysis

BACKGROUND AND OBJECTIVES

Fractures are a major source of morbidity and mortality in patients receiving dialysis. We sought to determine whether rates of fractures and tendon ruptures vary geographically.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data from the US Renal Data System were used to create four yearly cohorts, 2007-2010, including all eligible prevalent patients on hemodialysis in the United States on January 1 of each year. A secondary analysis comprising patients in a large dialysis organization conducted over the same period permitted inclusion of patient-level markers of mineral metabolism. Patients were grouped into 10 regions designated by the Centers for Medicare and Medicaid Services and divided by latitude into one of three bands: south, <35°; middle, 35° to <40°; and north, ≥40°. Poisson regression was used to calculate unadjusted and adjusted region-level rate ratios for events.

RESULTS

Overall, 327,615 patients on hemodialysis were included. Mean (SD) age was 61.8 (15.0) years old, 52.7% were white, and 55.0% were men. During 716,962 person-years of follow-up, 44,014 fractures and tendon ruptures occurred, the latter being only 0.3% of overall events. Event rates ranged from 5.36 to 7.83 per 100 person-years, a 1.5-fold rate difference across regions. Unadjusted region-level rate ratios varied from 0.83 (95% confidence interval, 0.81 to 0.85) to 1.20 (95% confidence interval, 1.18 to 1.23), a 1.45-fold rate difference. After adjustment for a wide range of case mix variables, a 1.33-fold variation in rates remained. Rates were higher in north and middle bands than the south (north rate ratio, 1.18; 95% confidence interval, 1.13 to 1.23; middle rate ratio, 1.13; 95% confidence interval, 1.10 to 1.17). Latitude explained 11% of variation, independent of region. A complementary analysis of 87,013 patients from a large dialysis organization further adjusted for circulating mineral metabolic parameters and protein energy wasting yielded similar results.

CONCLUSIONS

Rates of fractures vary geographically in the United States dialysis population, even after adjustment for known patient characteristics. Latitude seems to contribute to this phenomenon, but additional analyses exploring whether other factors might influence variation are warranted.

Dynamics of cinacalcet use and biochemical control in hemodialysis patients: a retrospective New-user cohort design

Background

Cinacalcet is used to treat secondary hyperparathyroidism among hemodialysis patients. Large-scale epidemiologic studies describing patterns of cinacalcet use, effects on parathyroid hormone (PTH), calcium, and phosphorous levels, and predictors of discontinuation have not been previously reported.

Methods

This retrospective cohort study used a clinical database of a large U.S. dialysis provider (2007–2010) merged with administrative data from the United States Renal Data System. Among new users of cinacalcet with Medicare coverage, trends in PTH, calcium, and phosphorus were measured in 30-day intervals following cinacalcet initiation.

Results

Seventeen thousand seven hundred sixty-three eligible initiators contributed 111,047 30-day follow-up intervals. Of these, 56 % discontinued cinacalcet by month 4. Of those discontinuing, 76.3 % reinitiated. Mean values of PTH, calcium, and phosphorus decreased to recommended levels within 4 months following initiation. Proximal PTH levels <150 pg/mL were associated with discontinuation: HR = 1.23 (95 % CI: 1.12, 1.36), whereas low calcium (<7.5 mg/dL) was suggestive of an association, HR = 1.09 (95 % CI 0.91, 1.32). Being in the Part D gap period increased discontinuation risk: HR = 1.09 (95 % CI: 1.03, 1.16). Low-income subsidy status decreased discontinuation risk: HR = 0.77 (95 % CI 0.69, 0.86). Predictors of reinitiation included low-income subsidy, HR = 1.32 (95 % CI 1.22, 1.43); higher albumin level, HR = 1.23 (95 % CI 1.10, 1.36) and higher calcium level, HR = 1.26 (95 % CI 1.19, 1.33).

Conclusions

Substantial and expected declines in laboratory values occurred following cinacalcet initiation. Early discontinuation and reinitiation of cinacalcet were common and may have occurred for clinical and economic reasons.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0174-6) contains supplementary material, which is available to authorized users.

Changes in secondary hyperparathyroidism-related biochemical parameters and medication use following parathyroidectomy

BACKGROUND

Little is known about changes in parathyroid hormone (PTH), calcium and phosphorous levels after parathyroidectomy in hemodialysis patients. We studied the effects of parathyroidectomy on these biochemical values in a large cohort of patients receiving maintenance hemodialysis.

METHODS

This retrospective cohort study included patients identified in both the United States Renal Data System and the database of a large dialysis organization who underwent parathyroidectomy in 2007-09, were aged ≥ 18 years, had Medicare Parts A and B as primary payer and had received hemodialysis for ≥ 1 year pre-parathyroidectomy. Descriptive statistics were calculated for continuous variables; categorical variables were used to characterize the population and evaluate monthly laboratory and medication use; median values were calculated for laboratory measures.

RESULTS

Among 1402 parathyroidectomy patients, mean age was 48.9 years, 52.4% were males, 58.8% were African American and mean dialysis duration was 7.5 years. Median PTH levels increased over the year before parathyroidectomy from 1039 to 1661 pg/mL and decreased afterward to 98 pg/mL at 1 month; levels remained ≥ 897 pg/mL for 10% of patients. Median calcium levels fell from 9.6 mg/dL before to 7.9 mg/dL 1 month after parathyroidectomy; levels were ≤ 7.1 mg/dL for 25% and remained ≤ 7.2 mg/dL for the lowest 25% at 3 months. Median phosphorous level was 6.8 mg/dL immediately before parathyroidectomy, decreased to 3.8 mg/dL immediately after and reached 5.8 mg/dL at 1 year.

CONCLUSIONS

While PTH levels dropped after parathyroidectomy for most patients, surgery was sometimes ineffective in reducing levels and sometimes led to over-suppression. Hypocalcemia could be profound and long lasting, suggesting the need for prolonged vigilance.

Management of serum calcium reductions among patients on hemodialysis following cinacalcet initiation

PURPOSE

Cinacalcet is indicated for treatment of secondary hyperparathyroidism in patients receiving hemodialysis. Cinacalcet reduces serum calcium concentrations by decreasing parathyroid hormone secretion, but the frequency and degree of calcium reduction following cinacalcet initiation, subsequent physician response, and ultimate calcium recovery in clinical practice are not well described.

METHODS

Patients receiving hemodialysis at a large dialysis organization who enrolled in the organization's prescription benefits service and initiated cinacalcet at serum calcium ≥8.4 mg/dL were studied (N = 13 723). Patients were categorized by whether they experienced a reduction in calcium to <8.4 mg/dL and to what level (<7.5, 7.5-7.9, and 8.0-8.3 mg/dL). Baseline characteristics, frequency of subsequent intervention, and calcium recovery were compared.

RESULTS

Of those who experienced a reduction in calcium to <8.4 mg/dL (n = 6437 [46.9%]), 6.6% had calcium <7.5 mg/dL and 24.5% had calcium 7.5-7.9 mg/dL, while the majority (68.9%) had a level of 8-8.3 mg/dL. Higher baseline parathyroid hormone and alkaline phosphatase were associated with lower resultant calcium. Among patients with calcium reductions, 45.6-63.5% received one or more directed clinical therapeutic responses, including 15.6-28.4% for whom cinacalcet was discontinued; the majority of patients recovered to calcium ≥8.4 mg/dL within 90 days of first detection. Only modest differences in recovery were noted between patients who did and did not receive any therapeutic response and patients who did and did not discontinue cinacalcet.

CONCLUSION

Serum calcium reductions following cinacalcet initiation were common; declines <7.5 mg/dL were infrequent. Calcium recovery occurred in the majority of patients, with or without therapeutic intervention.

Refining the definition of clinically important mineral and bone disorder in hemodialysis patients

BACKGROUND

It is important to identify an easily defined subset of patients at increased risk of adverse clinical outcomes associated with mineral and bone disorder (MBD) biomarkers (parathyroid hormone, calcium and phosphate).

METHODS

Observational cohort study of 26 221 prevalent hemodialysis patients in Davita clinics as of 31 August 2005 and followed up until 31 December 2006 (16 months). Predictors were 12 possible definitions of 'clinically important' MBD based on all 3 biomarkers, and 18 alternative definitions based on only 1 or 2 biomarkers. Events were death alone and a composite of cardiovascular hospitalization or death. Excess events were calculated based on a multivariate Cox model using 5224 patients in target for all MBD biomarkers and applied to 20 997 patients out of target for at least one biomarker. Excess events attributable to MBD were estimated by subtracting the multivariate model-derived predicted number from the actual number. Outcomes were the proportion of excess events attributable to MBD captured by each definition (threshold ≥70%) and the reduction in the population size considered to have clinically important MBD (threshold ≥30%). The excess fraction was excess events divided by actual events.

RESULTS

Patients with more biochemical markers out of target tended to be younger, black and have longer times since starting dialysis. The excess fraction associated with MBD ranged from ∼10 to 26% depending on the clinical endpoint and definition. The only definition to meet the thresholds required at least two of the three MBD biomarkers to be out of target (high or low). It captured 82% of excess composite endpoints and 74% of excess deaths and reduced the at-risk population by 46%.

CONCLUSIONS

Patients with at least two of three MBD biomarkers out of target represent a subgroup of patients at elevated risk of adverse clinical events.

Trends in anemia management practices in patients receiving hemodialysis and peritoneal dialysis: a retrospective cohort analysis

BACKGROUND/AIMS

Recent changes in clinical practice guidelines and reimbursement policies may have affected the use of anemia-related medications and red blood cell (RBC) transfusions in peritoneal dialysis (PD) and hemodialysis (HD) patients. We sought to compare patterns of erythropoiesis-stimulating agents (ESA) and intravenous (IV) iron use, achieved hemoglobin levels, and RBC transfusion use in PD and HD patients.

METHODS

In quarterly cohorts of prevalent dialysis patients receiving persistent therapy (>3 months), 2007-2011, with Medicare Parts A and B coverage, we assessed ESA and IV iron use and dose, RBC transfusions, and hemoglobin levels. Quarterly transfusion rates were calculated.

RESULTS

Observable PD and HD patients numbered 14,958 and 221,866 in Q1/2007 and 17,842 and 256,942 in Q4/2011. Adjusted ESA use was lower in PD (71.4-80.1%) than in HD (86.9-92.0%) patients, decreasing from 80.1% (Q1/2010) to 71.4% (Q4/2011) in PD patients, and from 92.0 to 86.9% in HD patients. The mean adjusted ESA dose decreased by 67.5% in PD and 58.4% in HD patients. IV iron use tended to increase, peaking at 39.3% for PD (Q3/2011) and 80.5% for HD (Q2/2011) patients. Adjusted mean hemoglobin levels fell from 11.7 to 10.6 mg/dl in PD and from 12.0 to 10.7 mg/dl in HD ESA users; adjusted transfusion rates increased from 2.4 to 3.0 per 100 patient-months in PD and from 2.6 to 3.3 in HD patients.

CONCLUSIONS

In patients receiving persistent dialysis, dose and frequency of ESA administrations decreased during the period 2007-2011. Mean hemoglobin levels decreased by more than 1 g/dl, while transfusion rates increased by approximately 25%.

Comparative changes in treatment practices and clinical outcomes following implementation of a prospective payment system: the STEPPS study

BACKGROUND

The aim of the US dialysis Prospective Payment System bundle, launched in January 2011, was reduction and more accurate prediction of costs of services, whilst maintaining or improving patient care. Dialysis facilities could either adopt the bundle completely (100%) in the first year of launch, or phase-in (25%) over four years. Differences in practice patterns and patient outcomes were hypothesized to occur in facilities that phased-in 25% compared to those that did not.

METHODS

Data are from STEPPS, a study of 51 small dialysis organization facilities designed to describe trends in dialytic treatment before and after bundle implementation. Baseline was defined as October-December 2010; follow-up as January-December 2011. Facility- and patient-level data were collected at enrollment and regularly thereafter. Cox proportional hazards and linear multi-level models were used to estimate the effect of opting-in 25% (vs. 100%) on practice patterns and clinical outcomes.

RESULTS

12 facilities (patient n = 346) opted-in 25% and 37 facilities (patient n = 1296) opted-in 100% to the dialysis bundle. At baseline, patients at 25% facilities were primarily covered by Medicare, were more likely to be black, and were receiving higher monthly epoetin alfa (EPO) doses. Throughout 2011, patients in 100% facilities received lower monthly EPO doses, and had lower mean hemoglobin concentrations; hospitalization and mortality rates were numerically lower in 25% facilities but not statistically different.

CONCLUSIONS

The economic pressure for dialysis providers to work within an expanded composite rate bundle whilst maintaining patient care may be a driver of practice indicator outcomes. Additional investigations are warranted to more precisely estimate clinical outcomes in patients attending facilities enrolling into the bundle 100% relative to the previous fee-for-service framework.

Parathyroid hormone change after cinacalcet initiation and one-year clinical outcome risk: a retrospective cohort study

BACKGROUND

Cinacalcet reduces parathyroid hormone (PTH) levels in patients receiving hemodialysis, but no non-experimental studies have evaluated the association between changes in PTH levels following cinacalcet initiation and clinical outcomes. We assessed whether short-term change in PTH levels after first cinacalcet prescription could serve as a surrogate marker for improvements in longer-term clinical outcomes.

METHODS

United States Renal Data System data were linked with data from a large dialysis organization. We created a point prevalent cohort of adult hemodialysis patients with Medicare as primary payer who initiated cinacalcet November 1, 2004-February 1, 2007, and were on cinacalcet for ≥ 40 days. We grouped patients into quartiles of PTH change after first cinacalcet prescription. We used Cox proportional hazard modeling to evaluate associations between short-term PTH change and time to first composite event (hospitalization for cardiovascular events or mortality) within 1 year. Overall models and models stratified by baseline PTH levels were adjusted for several patient-related factors.

RESULTS

For 2485 of 3467 included patients (72%), PTH levels decreased after first cinacalcet prescription; for 982 (28%), levels increased or were unchanged. Several characteristics differed between PTH change groups, including age and mineral-and-bone-disorder laboratory values. In adjusted models, we did not identify an association between greater short-term PTH reduction and lower composite event rates within 1 year, overall or in models stratified by baseline PTH levels.

CONCLUSIONS

Short-term change in PTH levels after first cinacalcet prescription does not appear to be a useful surrogate for longer-term improvements in cardiovascular or survival risk.

Clinical outcomes after parathyroidectomy in a nationwide cohort of patients on hemodialysis

BACKGROUND AND OBJECTIVES

Patients receiving dialysis undergo parathyroidectomy to improve laboratory parameters in resistant hyperparathyroidism with the assumption that clinical outcomes will also improve. However, no randomized clinical trial data demonstrate the benefits of parathyroidectomy. This study aimed to evaluate clinical outcomes up to 1 year after parathyroidectomy in a nationwide sample of patients receiving hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using data from the US Renal Data System, this study identified prevalent hemodialysis patients aged ≥18 years with Medicare as primary payers who underwent parathyroidectomy from 2007 to 2009. Baseline characteristics and comorbid conditions were assessed in the year preceding parathyroidectomy; clinical events were identified in the year preceding and the year after parathyroidectomy. After parathyroidectomy, patients were censored at death, loss of Medicare coverage, kidney transplant, change in dialysis modality, or 365 days. This study estimated cause-specific event rates for both periods and rate ratios comparing event rates in the postparathyroidectomy versus preparathyroidectomy periods.

RESULTS

Of 4435 patients who underwent parathyroidectomy, 2.0% died during the parathyroidectomy hospitalization and the 30 days after discharge. During the 30 days after discharge, 23.8% of patients were rehospitalized; 29.3% of these patients required intensive care. In the year after parathyroidectomy, hospitalizations were higher by 39%, hospital days by 58%, intensive care unit admissions by 69%, and emergency room/observation visits requiring hypocalcemia treatment by 20-fold compared with the preceding year. Cause-specific hospitalizations were higher for acute myocardial infarction (rate ratio, 1.98; 95% confidence interval, 1.60 to 2.46) and dysrhythmia (rate ratio 1.4; 95% confidence interval1.16 to 1.78); fracture rates did not differ (rate ratio 0.82; 95% confidence interval 0.6 to 1.1).

CONCLUSIONS

Parathyroidectomy is associated with significant morbidity in the 30 days after hospital discharge and in the year after the procedure. Awareness of clinical events will assist in developing evidence-based risk/benefit determinations for the indication for parathyroidectomy.

Predialysis care and dialysis outcomes in hemodialysis patients with a functioning fistula

BACKGROUND/AIMS

Predialysis care has been associated with improved first-year outcomes. We investigated types of predialysis care associated with improved patient outcomes in patients initiating dialysis with a fistula and at least 2 years of predialysis care.

METHODS

In this retrospective cohort of incident hemodialysis patients with ≥2 years of Medicare coverage before dialysis initiation, care patterns and patients were determined using Medicare claims. Fistula use at initiation was ascertained from the Medical Evidence Report.

RESULTS

Patients aged ≥67 years who initiated hemodialysis with a fistula (n = 14,459) differed demographically and clinically from patients who initiated with other vascular access types; however, 55% had diabetes, 28% heart failure, and 40% ischemic heart disease. In the year preceding initiation, 88% of these patients visited a nephrologist, 66% a cardiologist, 9% an endocrinologist, and 3% a dietician; most underwent routine laboratory measurements. In the first year of dialysis, 50% were hospitalized and 1.3% underwent transplant; the mortality rate remained constant (∼20 per 100 patient-years). Of predialysis care factors evaluated, only fistula placement more than 1 month before dialysis initiation was associated with lower hospitalization and mortality risk and greater likelihood of transplant. Other potentially modifiable factors included more contact with cardiologists and endocrinologists.

CONCLUSION

Patients initiating dialysis with a functioning fistula appear to receive substantial predialysis preparation. This selected population does not show the excess mortality risk often observed early in dialysis treatment. Earlier fistula placement and referral to cardiology and endocrinology appear to be important aspects of predialysis care.

High rates of death and hospitalization follow bone fracture among hemodialysis patients

Altered bone structure and function contribute to the high rates of fractures in dialysis patients compared to the general population. Fracture events may increase the risk of subsequent adverse clinical outcomes. Here we assessed the incidence of post-fracture morbidity and mortality in an international cohort of 34,579 in-center hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS). We estimated country-specific rates of fractures requiring a hospital admission and associated length of stay in the hospital. Incidence rates of death and of a composite event of death/rehospitalization were estimated for 1 year after fracture. Overall, 3% of participants experienced a fracture. Fracture incidence varied across countries, from 12 events/1000 patient-years (PY) in Japan to 45/1000 PY in Belgium. In all countries, fracture rates were higher in the hemodialysis group compared to those reported for the general population. Median length of stay ranged from 7 to 37 days in the United States and Japan, respectively. In most countries, postfracture mortality rates exceeded 500/1000 PY and death/rehospitalization rates exceeded 1500/1000 PY. Fracture patients had higher unadjusted rates of death (3.7-fold) and death/rehospitalization (4.0-fold) compared to the overall DOPPS population. Mortality and hospitalization rates were highest in the first month after the fracture and declined thereafter. Thus, the high frequency of fractures and increased adverse outcomes following a fracture pose a significant health burden for dialysis patients. Fracture prevention strategies should be identified and applied broadly in nephrology practices.

Effect of facility-level hemoglobin concentration on dialysis patient risk of transfusion

BACKGROUND

Changes in anemia management practices due to concerns about erythropoiesis-stimulating agent safety and Medicare payment changes may increase patient risk of transfusion. We examined anemia management trends in hemodialysis patients and risk of red blood cell (RBC) transfusion according to dialysis facility-level hemoglobin concentration.

STUDY DESIGN

Retrospective follow-up study; 6-month study period (January to June), 3-month exposure/follow-up.

SETTING & PARTICIPANTS

For each year in 2007-2011, annual cohorts of point-prevalent Medicare primary payer patients receiving hemodialysis on January 1 with one or more hemoglobin measurements during the study period. Annual cohorts averaged 170,000 patients, with 130,000 patients and 3,100 facilities for the risk analysis.

PREDICTOR

Percentage of facility patient-months with hemoglobin level<10 g/dL.

OUTCOME

Patient-level RBC transfusion rates.

MEASUREMENTS

Monthly epoetin alfa and intravenous iron doses, mean hemoglobin levels, and RBC transfusion rates; percentage of facility patient-months with hemoglobin levels<10 g/dL (exposure) and patient-level RBC transfusion rates (follow-up).

RESULTS

Percentages of patients with hemoglobin levels<10 g/dL increased every year from 2007 (6%) to 2011 (~11%). Epoetin alfa doses, iron doses, and transfusion rates remained relatively stable through 2010 and changed in 2011. Median monthly epoetin alfa and iron doses decreased 25% and 43.8%, respectively, and monthly transfusion rates increased from 2.8% to 3.2% in 2011, a 14.3% increase. Patients in facilities with the highest prevalence of hemoglobin levels<10 g/dL over 3 months were at ~30% elevated risk of receiving RBC transfusions within the next 3 months (relative risk, 1.28; 95% CI, 1.22-1.34).

LIMITATIONS

Possibly incomplete claims data; smaller units excluded; hemoglobin levels reported monthly for patients receiving epoetin alfa; transfusions usually not administered in dialysis units.

CONCLUSIONS

Dialysis facility treatment practices, as assessed by percentage of patient-months with hemoglobin levels<10 g/dL over 3 months, were associated significantly with risk of transfusions in the next 3 months for all patients in the facility, regardless of patient case-mix.

Sensitization from transfusion in patients awaiting primary kidney transplant

BACKGROUND

Sensitization to human leukocyte antigen (HLA) from red blood cell (RBC) transfusion is poorly quantified and is based on outdated, insensitive methods. The objective was to evaluate the effect of transfusion on the breadth, magnitude and specificity of HLA antibody formation using sensitive and specific methods.

METHODS

Transfusion, demographic and clinical data from the US Renal Data System were obtained for patients on dialysis awaiting primary kidney transplant who had ≥ 2 HLA antibody measurements using the Luminex single-antigen bead assay. One cohort included patients with a transfusion (n = 50) between two antibody measurements matched with up to four nontransfused patients (n = 155) by age, sex, race and vintage (time on dialysis). A second crossover cohort (n = 25) included patients with multiple antibody measurements before and after transfusion. We studied changes in HLA antibody mean fluorescence intensity (MFI) and calculated panel reactive antibody (cPRA).

RESULTS

In the matched cohort, 10 of 50 (20%) transfused versus 6 of 155 (4%) nontransfused patients had a ≥ 10 HLA antibodies increase of >3000 MFI (P = 0.0006); 6 of 50 (12%) transfused patients had a ≥ 30 antibodies increase (P = 0.0007). In the crossover cohort, the number of HLA antibodies increasing >1000 and >3000 MFI was higher in the transfused versus the control period, P = 0.03 and P = 0.008, respectively. Using a ≥ 3000 MFI threshold, cPRA significantly increased in both matched (P = 0.01) and crossover (P = 0.002) transfused patients.

CONCLUSIONS

Among prospective primary kidney transplant recipients, RBC transfusion results in clinically significant increases in HLA antibody strength and breadth, which adversely affect the opportunity for future transplant.

Worldwide, mortality risk is high soon after initiation of hemodialysis

Mortality rates for maintenance hemodialysis patients are much higher than the general population and are even greater soon after starting dialysis. Here we analyzed mortality patterns in 86,886 patients in 11 countries focusing on the early dialysis period using data from the Dialysis Outcomes and Practice Patterns Study, a prospective cohort study of in-center hemodialysis. The primary outcome was all-cause mortality, using time-dependent Cox regression, stratified by study phase adjusted for age, sex, race, and diabetes. The main predictor was time since dialysis start as divided into early (up to 120 days), intermediate (121-365 days), and late (over 365 days) periods. Mortality rates (deaths/100 patient-years) were 26.7 (95% confidence intervals 25.6-27.9), 16.9 (16.2-17.6), and 13.7 (13.5-14.0) in the early, intermediate, and late periods, respectively. In each country, mortality was higher in the early compared to the intermediate period, with a range of adjusted mortality ratios from 3.10 (2.22-4.32) in Japan to 1.15 (0.87-1.53) in the United Kingdom. Adjusted mortality rates were similar for intermediate and late periods. The ratio of elevated mortality rates in the early to the intermediate period increased with age. Within each period, mortality was higher in the United States than in most other countries. Thus, internationally, the early hemodialysis period is a high-risk time for all countries studied, with substantial differences in mortality between countries. Efforts to improve outcomes should focus on the transition period and the first few months of dialysis.

Temporal trends in fracture rates and postdischarge outcomes among hemodialysis patients

Patients with ESRD have a substantially increased risk of bone fractures, but the burden of fractures has not been sufficiently characterized in this population. Here, we analyzed fracture rates and postdischarge outcomes using Medicare data from hemodialysis patients in the United States between 2000 and 2009. We assessed adjusted quarterly fracture rates (inpatient and outpatient) and consequences of postfracture hospitalization for seven categories of fracture location. Pelvis/hip, vertebral, and lower leg fractures were the most prevalent fracture types. Pelvis/hip fractures declined slightly from 29.6 to 20.6 per 1000 patient-years between early 2000 and late 2009, but the incidence rates for all other fracture types remained relatively constant. Median lengths of stay for the primary fracture hospitalization ranged from 5 days (interquartile range [IQR], 3-9 days) for forearm/wrist fractures to 8 days (IQR, 5-12 days) for femur fractures. The proportion of patients discharged from the primary hospitalization to a skilled-nursing facility ranged from 28% (ribs/sternum) to 47% (pelvis/hip). A negative binomial regression model suggested that patients had an adjusted mean of 3.8-5.2 additional hospitalizations during the year after discharge from the index hospitalization, varying by fracture type, comprising a mean of 33-52 inpatient days. Case-mix-adjusted mortality rates after discharge ranged from 0.43 to 0.91 per patient-year and were highest for vertebral, pelvis/hip, and femur fractures. In conclusion, fractures in the dialysis population are common and are associated with a substantially increased risk for death and hospitalization.

Temporal trends in fracture rates and postdischarge outcomes among hemodialysis patients

Patients with ESRD have a substantially increased risk of bone fractures, but the burden of fractures has not been sufficiently characterized in this population. Here, we analyzed fracture rates and postdischarge outcomes using Medicare data from hemodialysis patients in the United States between 2000 and 2009. We assessed adjusted quarterly fracture rates (inpatient and outpatient) and consequences of postfracture hospitalization for seven categories of fracture location. Pelvis/hip, vertebral, and lower leg fractures were the most prevalent fracture types. Pelvis/hip fractures declined slightly from 29.6 to 20.6 per 1000 patient-years between early 2000 and late 2009, but the incidence rates for all other fracture types remained relatively constant. Median lengths of stay for the primary fracture hospitalization ranged from 5 days (interquartile range [IQR], 3-9 days) for forearm/wrist fractures to 8 days (IQR, 5-12 days) for femur fractures. The proportion of patients discharged from the primary hospitalization to a skilled-nursing facility ranged from 28% (ribs/sternum) to 47% (pelvis/hip). A negative binomial regression model suggested that patients had an adjusted mean of 3.8-5.2 additional hospitalizations during the year after discharge from the index hospitalization, varying by fracture type, comprising a mean of 33-52 inpatient days. Case-mix-adjusted mortality rates after discharge ranged from 0.43 to 0.91 per patient-year and were highest for vertebral, pelvis/hip, and femur fractures. In conclusion, fractures in the dialysis population are common and are associated with a substantially increased risk for death and hospitalization.

Geographic variation in CKD prevalence and ESRD incidence in the United States: results from the reasons for geographic and racial differences in stroke (REGARDS) study

BACKGROUND

It is not known whether geographic differences in the prevalence of chronic kidney disease exist and are associated with end-stage renal disease (ESRD) incidence rates across the United States.

STUDY DESIGN

Cross-sectional and ecologic.

SETTING & PARTICIPANTS

White (n = 16,410) and black (n = 11,109) participants from across the continental United States in the population-based Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

PREDICTOR

Geographic region, defined by the 18 networks of the US ESRD Network Program.

OUTCOMES & MEASUREMENTS

Albuminuria, defined as albumin-creatinine ratio ≥30 mg/g, and decreased estimated glomerular filtration rate (eGFR), defined as <60 mL/min/1.73 m(2), were measured in the REGARDS Study. ESRD incidence rates were obtained from the US Renal Data System.

RESULTS

For whites, the network-specific prevalence of albuminuria ranged from 8.4% (95% CI, 3.3%-13.5%) in Network 15 to 14.8% (95% CI, 8.0%-21.6%) in Network 3, and decreased eGFR ranged from 4.3% (95% CI, 2.0%-6.6%) in Network 4 to 16.7% (95% CI, 12.7%-20.7%) in Network 7. For blacks, the prevalence of albuminuria ranged from 12.1% (95% CI, 8.7%-15.5%) in Network 5 to 26.5% (95% CI, 16.7%-36.3%) in Network 4, and decreased eGFR ranged from 6.7% (95% CI, 5.0%-8.4%) in Network 17/18 to 13.4% (95% CI, 7.8%-19.1%) in Network 12. Spearman correlation coefficients for the prevalence of albuminuria and decreased eGFR with network-specific ESRD incidence rates were 0.49 and 0.24, respectively, for whites and 0.29 and 0.25, respectively, for blacks.

LIMITATIONS

There were few cases of albuminuria and decreased eGFR in some geographic regions.

CONCLUSIONS

In the United States, substantial geographic variations in the prevalence of albuminuria and decreased eGFR exist, but were correlated only modestly with ESRD incidence, suggesting the chronic kidney disease burden may not explain the geographic variation in ESRD incidence.

Red blood cell transfusion use in patients with chronic kidney disease

BACKGROUND

There is limited data available on the use of red blood cell (RBC) transfusions in younger chronic kidney disease patients not on dialysis (CKD-ND), for whom the consequences of developing antibodies to foreign antigens (allosensitization) may be particularly relevant.

METHODS

We used the Ingenix medical claims database, comprising data on ∼40 million commercially insured US individuals, to identify annual (2002-08) cohorts of patients 18-64 years of age with newly diagnosed CKD. We followed each cohort for 1 year to estimate RBC transfusion rates and used Cox proportional hazards regression to identify patient characteristics associated with time to first transfusion.

RESULTS

We identified 120 790 newly diagnosed CKD patients for the years 2002-08; 54% were 50-64 years of age. Overall, the transfusion rate was 2.64/100 person-years (PYs) (95% CI: 2.52-2.77). Rates were higher among those with diagnosed anemia [9.80/100 PYs (95% CI: 9.31-10.3)] and among those who progressed to end-stage renal disease (ESRD) [28.0/100 PYs (95% CI: 23.7-33.0)]. For those progressing to ESRD, transfusion rates more than doubled between 2002 and 2008. Of the factors evaluated, transfusion history and the presence of heart failure and diabetes were most strongly associated with a receipt of a transfusion.

CONCLUSIONS

RBC transfusions are relatively common and on the rise among younger CKD-ND patients who are anemic and progress to ESRD. Efforts to decrease the use of transfusions may be important for potential transplant candidates who progress to ESRD.