The Impact of Disability and Social Determinants of Health on Condition-Specific Readmissions beyond Medicare Risk Adjustments: A Cohort Study

Background: Readmission rates after pneumonia, heart failure, and acute myocardial infarction hospitalizations are risk-adjusted for age, gender, and medical comorbidities and used to penalize hospitals. Objective: To assess the impact of disability and social determinants of health on condition-specific readmissions beyond current risk adjustment. Design, Setting, and Participants: Retrospective cohort study of Medicare patients using 1) linked Health and Retirement Study-Medicare claims data (HRS-CMS) and 2) Healthcare Cost and Utilization Project State Inpatient Databases (Florida, Washington) linked with ZIP Code-level measures from the Census American Community Survey (ACS-HCUP). Multilevel logistic regression models assessed the impact of disability and selected social determinants of health on readmission beyond current risk adjustment. Main Measures: Outcomes measured were readmissions ≤30 days after hospitalizations for pneumonia, heart failure, or acute myocardial infarction. HRS-CMS models included disability measures (activities of daily living [ADL] limitations, cognitive impairment, nursing home residence, home healthcare use) and social determinants of health (spouse, children, wealth, Medicaid, race). ACS-HCUP model measures were ZIP Code-percentage of residents ≥65 years of age with ADL difficulty, spouse, income, Medicaid, and patient-level and hospital-level race. Key Results: For pneumonia, ≥3 ADL difficulties (OR 1.61, CI 1.079–2.391) and prior home healthcare needs (OR 1.68, CI 1.204–2.355) increased readmission in HRS-CMS models (N = 1631); ADL difficulties (OR 1.20, CI 1.063–1.352) and ‘other’ race (OR 1.14, CI 1.001–1.301) increased readmission in ACS-HCUP models (N = 27,297). For heart failure, children (OR 0.66, CI 0.437–0.984) and wealth (OR 0.53, CI 0.349–0.787) lowered readmission in HRS-CMS models (N = 2068), while black (OR 1.17, CI 1.056–1.292) and ‘other’ race (OR 1.14, CI 1.036-1.260) increased readmission in ACS-HCUP models (N = 37,612). For acute myocardial infarction, nursing home status (OR 4.04, CI 1.212–13.440) increased readmission in HRS-CMS models (N = 833); ‘other’ patient-level race (OR 1.18, CI 1.012–1.385) and hospital-level race (OR 1.06, CI 1.001–1.125) increased readmission in ACS-HCUP models (N = 17,496). Conclusions: Disability and social determinants of health influence readmission risk when added to the current Medicare risk adjustment models, but the effect varies by condition.