The impact of paradoxical comorbidities on risk-adjusted mortality of Medicare beneficiaries with cardiovascular disease

Prognostic impact of comorbidity measures on outcomes following acute coronary syndrome: A systematic review

AIM

To identify existing comorbidity measures and summarise their association with acute coronary syndrome (ACS) outcomes.

METHODS

We searched published studies from MEDLINE (OVIDSP) and EMBASE from inception to March 2021, studies of the pre-specified conference proceedings from Web of Science since May 2017, and studies included in any relevant systematic reviews. Studies that reported no comorbidity measures, no association of comorbid burden with ACS outcomes, or only used a comorbidity measure as a confounder without further information were excluded. After independent screening by three reviewers, data extraction and risk of bias assessment of each included study was undertaken. Results were narratively synthesised.

RESULTS

Of 4166 potentially eligible studies identified, 12 (combined n = 6 885 982 participants) were included. Most studies had a high risk of bias at quality assessment. Six different types of comorbidity measures were identified with the Charlson comorbidity index (CCI) the most widely used measure among studies. Overall, the greater the comorbid burden or the higher comorbidity scores recorded, the greater was the association with the risk of mortality.

CONCLUSION

The review summarised different comorbidity measures and reported that higher comorbidity scores were associated with worse ACS outcomes. The CCI is the most widely measure of comorbid burden and shows additive value to clinical risk scores in use.

Utilization of Advanced Cardiovascular Therapies in the United States and Canada: An Observational Study of New York and Ontario Administrative Data

BACKGROUND

Endovascular aortic aneurysm repair (EVAR), left ventricular assist device (LVAD), and transcatheter aortic valve replacement (TAVR) are expensive cardiovascular technologies with potential to benefit large numbers of patients. There are few population-based studies comparing utilization between countries. Our objective was to compare patient characteristics and utilization patterns of EVAR, LVAD, and TAVR in Ontario, Canada, and New York State, United States.

METHODS AND RESULTS

We performed a retrospective cohort study using administrative data to identify all adults who received EVAR, LVAD, or TAVR in Ontario and New York between 2012 and 2015. We compared socio-demographics of EVAR, LVAD, and TAVR recipients in Ontario and New York. We compared standardized utilization rates between jurisdictions for each procedure. We identified 3295 EVAR recipients from Ontario and 6236 from New York (mean age 74.6 versus 74.5 years; P=0.61): 136 LVAD recipients from Ontario and 686 from New York (age, 57.4 versus 57.7 years; P=0.80): 1708 TAVR recipients from Ontario and 4838 from New York (age, 83.1 versus 83.1; P=1.0). A significantly smaller percentage of EVAR and TAVR recipients in Ontario were female compared to New York (EVAR, 15.8% versus 22.1% female; P<0.001; TAVR, 45.9% versus 51.8%; P<0.001), but for LVAD the percentage female was similar (21.3% versus 20.8%; P=0.99). Utilization was significantly higher in New York for all procedures: EVAR (12.8 procedures per-100 000 adults per-year in Ontario, 20.2 in New York; P<0.001); LVAD (0.3 in Ontario versus 1.3 in New York; P<0.001); and TAVR (6.6 in Ontario, 14.3 in New York; P<0.001). Higher utilization of EVAR and TAVR in New York relative to Ontario increased substantially with increasing age.

CONCLUSIONS

We observed significantly higher utilization of EVAR, LVAD, and TAVR in New York compared to Ontario. Our results highlight important differences in how 2 different countries are using advanced cardiovascular therapies.

Hip fracture care in Manitoba, Canada and New York State, United States: an analysis of administrative data

BACKGROUND

Nearly 30 years ago, a series of studies showed increased hip fracture mortality in Manitoba compared to the United States, but these data have not been updated. Our objective was to compare the organization of hip fracture care and short-term outcomes in Manitoba and New York State using contemporary data.

METHODS

This was a retrospective cohort study of administrative data for all adults aged 50 years or more admitted to hospital with hip fracture between Jan. 1, 2011, and Oct. 31, 2013 in Manitoba and New York State. We compared the 2 jurisdictions with respect to: 1) the proportion of hospitals treating hip fracture and annual hip fracture volume, 2) hospital length of stay, 3) death and 4) hospital readmission. We used descriptive statistics, univariate methods and regression models to compare differences in care between jurisdictions.

RESULTS

We identified 2845 patients (mean age 82.2 yr, 2061 women [72.4%]) with hip fracture in Manitoba and 31 524 patients (mean age 81.9 yr, 22 973 women [72.9%]) with hip fracture in New York. A smaller proportion of hospitals in Manitoba than in New York treated hip fracture (7/30 [23%] v. 180/239 [75.3%]) (p < 0.001); the mean annual hospital hip fracture volume was higher in Manitoba (140.0) than in New York (68.9), but the difference did not reach statistical significance (p = 0.2). For patients with femoral neck fractures, the median hospital length of stay was longer in Manitoba than in New York (13 d v. 7 d). The rate of death within 7 days of admission was similar in Manitoba and New York (1.3% v. 2.0%, p = 0.07), although the rate of in-hospital death was higher in Manitoba (5.7% v. 3.5%, p < 0.001). Readmission within 30 days of discharge was less frequent in Manitoba than in New York (9.8% v. 12.0%, p = 0.02). Results were similar for patients with intertrochanteric fractures.

INTERPRETATION

Poor short-term outcomes for patients with hip fracture in Manitoba that were documented in the 1980s seem to have been eliminated. Our results should provide optimism that reengineering of clinical care can produce substantive improvements in quality.

The Relative Ability of Comorbidity Ascertainment Methodologies to Predict In-Hospital Mortality Among Hospitalized Community-acquired Pneumonia Patients

BACKGROUND

Despite widespread use of comorbidities for population health descriptions and risk adjustment, the ideal method for ascertaining comorbidities is not known. We sought to compare the relative value of several methodologies by which comorbidities may be ascertained.

METHODS

This is an observational study of 1596 patients admitted to the University of Chicago for community-acquired pneumonia from 1998 to 2012. We collected data via chart abstraction, administrative data, and patient report, then performed logistic regression analyses, specifying comorbidities as independent variables and in-hospital mortality as the dependent variable. Finally, we compared area under the curve (AUC) statistics to determine the relative ability of each method of comorbidity ascertainment to predict in-hospital mortality.

RESULTS

Chart review (AUC, 0.72) and administrative data (Charlson AUC, 0.83; Elixhauser AUC, 0.84) predicted in-hospital mortality with greater fidelity than patient report (AUC, 0.61). However, multivariate logistic regression analyses demonstrated that individual comorbidity derivation via chart review had the strongest relationship with in-hospital mortality. This is consistent with prior literature suggesting that administrative data have inherent, paradoxical biases with important implications for risk adjustment based solely on administrative data.

CONCLUSIONS

Although comorbidities derived through administrative data did produce an AUC greater than chart review, our analyses suggest a coding bias in several comorbidities with a paradoxically protective effect. Therefore, chart review, while labor and resource intensive, may be the ideal method for ascertainment of clinically relevant comorbidities.

Two morbidity indices developed in a nationwide population permitted performant outcome-specific severity adjustment

OBJECTIVE

The objective of the study was to develop and validate two outcome-specific morbidity indices in a population-based setting: the Mortality-Related Morbidity Index (MRMI) predictive of all-cause mortality and the Expenditure-Related Morbidity Index (ERMI) predictive of health care expenditure.

STUDY DESIGN AND SETTING

A cohort including all beneficiaries of the main French health insurance scheme aged 65 years or older on December 31, 2013 (N = 7,672,111), was randomly split into a development population for index elaboration and a validation population for predictive performance assessment. Age, gender, and selected lists of conditions identified through standard algorithms available in the French health insurance database (SNDS) were used as predictors for 2-year mortality and 2-year health care expenditure in separate models. Overall performance and calibration of the MRMI and ERMI were measured and compared to various versions of the Charlson Comorbidity Index (CCI).

RESULTS

The MRMI included 16 conditions, was more discriminant than the age-adjusted CCI (c-statistic: 0.825 [95% confidence interval: 0.824-0.826] vs. 0.800 [0.799-0.801]), and better calibrated. The ERMI included 19 conditions, explained more variance than the cost-adapted CCI (21.8% vs. 13.0%), and was better calibrated.

CONCLUSION

The proposed MRMI and ERMI indices are performant tools to account for health-state severity according to outcomes of interest.

Utilization and Short-Term Outcomes of Primary Total Hip and Knee Arthroplasty in the United States and Canada: An Analysis of New York and Ontario Administrative Data

OBJECTIVE

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are common and effective surgical procedures. This study sought to compare utilization and short-term outcomes of primary TKA and THA in adjacent regions of Canada and the United States.

METHODS

The study was designed as a retrospective cohort study of patients who underwent primary TKA or THA, comparing administrative data from New York and Ontario in 2012-2013. Demographic features of the TKA and THA patients, per capita utilization rates, and short-term outcomes were compared between the jurisdictions.

RESULTS

A higher percentage of New York hospitals performed TKA compared to Ontario hospitals (75.7% versus 42.1%; P < 0.001), and the mean annual procedural volume for TKAs was lower in New York hospitals (mean 179 versus 327 in Ontario hospitals; P < 0.001). After direct standardization, utilization was significantly lower in New York compared to Ontario, both for TKA (16.1 TKAs versus 21.4 TKAs per 10,000 population per year; P < 0.001) and for THA (10.5 THAs versus 11.5 THAs per 10,000 population per year; P < 0.001). For those who underwent TKA, the length of stay in Ontario hospitals was significantly longer (mean 3.7 days versus 3.4 days in New York hospitals; P < 0.001). A smaller percentage of New York patients were discharged directly home (46.2% versus 90.9% of Ontario patients; P < 0.001), but 30-day and 90-day readmission rates were higher in New York compared to Ontario (30-day rates, 4.6% versus 3.9% [P < 0.001]; 90-day rates, 8.4% versus 6.7% [P < 0.001]). For the THA cohorts, the results with regard to length of stay, discharge disposition, and readmission rates were similar to those for TKA.

CONCLUSION

Ontario has higher utilization of total joint arthroplasty than New York but has a smaller percentage of hospitals performing these procedures. Patients are more likely to be discharged home and less likely to be readmitted in Ontario. Our results suggest areas where each jurisdiction could improve.

Racial Differences in Hospital Death for Atrial Fibrillation: The National Inpatient Sample 2001-2012

BACKGROUND

Understanding racial differences in outcomes for atrial fibrillation (AF) may guide interventions to diminish health inequities.

METHODS AND RESULTS

In a retrospective, cross-sectional study of adults hospitalized with a principal diagnosis of AF using the 2001-2012 National Inpatient Sample, we assessed racial differences for in-hospital. We accounted for case-mix and clustering by race within hospitals to estimate odds ratios (OR) for death associated with individual patient race and hospital racial composition. We identified 676,567 hospitalizations (mean age 71.8 years, 53.6% women) with principal diagnosis of AF (84.2% White, 7.1% Black, 5.0% Hispanic). Black (vs. White) race was associated with 1.63-fold (95% CI, 1.50-1.78) risk of death. Other races had similar risk of death as Whites. Risk of death for Blacks (vs. Whites) declined over time [2001: OR 1.78(95% CI 1.31-2.43); 2012: OR 1.23(95% CI 0.92-1.64)]. Racial differences in deaths within hospitals narrowed, while hospitals with larger proportions of Blacks had persistently worse outcomes than hospitals with fewer Blacks (OR 1.08 per 10% increase in Blacks in 2001 and 2012).

CONCLUSION

Black patients with a principal diagnosis of AF were more likely to suffer in-hospital death than Whites. Our findings suggest racial disparities based upon individual patients' race improved over time, but outcomes were persistently worse at hospitals with higher proportions of Black patients, regardless of patients' races.

Effect of the Diagnosis of Inflammatory Bowel Disease on Risk-Adjusted Mortality in Hospitalized Patients with Acute Myocardial Infarction, Congestive Heart Failure and Pneumonia

Introduction

Measurement of mortality in patients with acute myocardial infarction (AMI), congestive heart failure (CHF) and pneumonia (PN) is a high priority since these are common reasons for hospitalization. However, mortality in patients with inflammatory bowel disease (IBD) that are hospitalized for these common medical conditions is unknown.

Methods

A retrospective review of the 2005–2011 National Inpatient Sample (NIS), (approximately a 20% sample of discharges from community hospitals) was performed. A dataset for all patients with ICD-9-CM codes for primary diagnosis of acute myocardial infarction, pneumonia or congestive heart failure with a co-diagnosis of IBD, Crohn’s disease (CD) or ulcerative colitis (UC). 1:3 propensity score matching between patients with co-diagnosed disease vs. controls was performed. Continuous variables were compared between IBD and controls. Categorical variables were reported as frequency (percentage) and analyzed by Chi-square tests or Fisher’s exact test for co-diagnosed disease vs. control comparisons. Propensity scores were computed through multivariable logistic regression accounting for demographic and hospital factors. In-hospital mortality between the groups was compared.

Results

Patients with IBD, CD and UC had improved survival after AMI compared to controls. 94/2280 (4.1%) of patients with IBD and AMI died, compared to 251/5460 (5.5%) of controls, p = 0.01. This represents a 25% improved survival in IBD patients that were hospitalized with AMI. There was a 34% improved survival in patients with CD and AMI. There was a trend toward worsening survival in patients with IBD and CHF. Patients with CD and PN had improved survival compared to controls. 87/3362 (2.59%) patients with CD and PN died, compared to 428/10076 (4.25%) of controls, p < .0001. This represents a 39% improved survival in patients with CD that are hospitalized for PN.

Conclusion

IBD confers a survival benefit for patients hospitalized with AMI. A diagnosis of CD benefits survival in patients that are hospitalized with PN.

Classification tree analysis of race-specific subgroups at risk for a central venous catheter-related bloodstream infection

BACKGROUND

Studies of racial disparities in patient safety events often do not use race-specific risk adjustment and do not account for reciprocal covariate interactions. These limitations were addressed by using classification tree analysis separately for black patients and white patients to identify characteristics that segment patients who have increased risks for a venous catheter-related bloodstream infection.

METHODS

A retrospective, cross-sectional analysis of 5,236,045 discharges from 103 Florida acute hospitals in 2005-2009 was conducted. Hospitals were rank ordered on the basis of the black/white Patient Safety Indicator (PSI) 7 rate ratio as follows: Group 1 (white rate higher), Group 2, (equivalent rates), Group 3, (black rate higher), and Group 4, (black rate highest). Predictor variables included 26 comorbidities (Elixhauser Comorbidity Index) and demographic characteristics. Four separate classification tree analyses were completed for each race/hospital group.

RESULTS

Individual characteristics and groups of characteristics associated with increased PSI 7 risk differed for black and white patients. The average age for both races was different across the hospital groups (p < .01). Weight loss was the strongest single delineator and common to both races. The black subgroups with the highest PSI 7 risk were Medicare beneficiaries who were either < or = 25.5 years without hypertension or < or = 39.5 years without hypertension but with an emergency or trauma admission. The white subgroup with the highest PSI 7 risk consisted of patients < or = 45.5 years who had congestive heart failure but did not have either hypertension or weight loss.

DISCUSSION

Identifying subgroups of patients at risk for a rare safety event such as PSI 7 should aid effective clinical decisions and efficient use of resources and help to guide patient safety interventions.

Total knee arthroplasty volume, utilization, and outcomes among Medicare beneficiaries, 1991-2010

CONTEXT

Total knee arthroplasty (TKA) is one of the most common and costly surgical procedures performed in the United States.

OBJECTIVE

To examine longitudinal trends in volume, utilization, and outcomes for primary and revision TKA between 1991 and 2010 in the US Medicare population.

DESIGN, SETTING, AND PARTICIPANTS

Observational cohort of 3,271,851 patients (aged ≥65 years) who underwent primary TKA and 318 563 who underwent revision TKA identified in Medicare Part A data files.

MAIN OUTCOME MEASURES

We examined changes in primary and revision TKA volume, per capita utilization, hospital length of stay (LOS), readmission rates, and adverse outcomes.

RESULTS

Between 1991 and 2010 annual primary TKA volume increased 161.5% from 93,230 to 243,802 while per capita utilization increased 99.2% (from 31.2 procedures per 10,000 Medicare enrollees in 1991 to 62.1 procedures per 10,000 in 2010). Revision TKA volume increased 105.9% from 9650 to 19,871 while per capita utilization increased 59.4% (from 3.2 procedures per 10,000 Medicare enrollees in 1991 to 5.1 procedures per 10,000 in 2010). For primary TKA, LOS decreased from 7.9 days (95% CI, 7.8-7.9) in 1991-1994 to 3.5 days (95% CI, 3.5-3.5) in 2007-2010 (P < .001). For primary TKA, rates of adverse outcomes resulting in readmission remained stable between 1991-2010, but rates of all-cause 30-day readmission increased from 4.2% (95% CI, 4.1%-4.2%) to 5.0% (95% CI, 4.9%-5.0%) (P < .001). For revision TKA, the decrease in hospital LOS was accompanied by an increase in all-cause 30-day readmission from 6.1% (95% CI, 5.9%-6.4%) to 8.9% (95% CI, 8.7%-9.2%) (P < .001) and an increase in readmission for wound infection from 1.4% (95% CI, 1.3%-1.5%) to 3.0% (95% CI, 2.9%-3.1%) (P < .001).

CONCLUSIONS

Increases in TKA volume have been driven by both increases in the number of Medicare enrollees and in per capita utilization. We also observed decreases in hospital LOS that were accompanied by increases in hospital readmission rates.