Prospective Comparison of 6 Comorbidity Indices as Predictors of 1-Year Post-Hospital Discharge Institutionalization, Readmission, and Mortality in Elderly Individuals

Abstract

Older patients often suffer from multiple comorbid conditions. Few comorbidity indices are valid and reliable in the elderly and were rarely compared. To compare the performance, relevance, and ability of 6 widely used and validated comorbidity indices--Charlson Comorbidity Index, Cumulative Illness Rating Scale-Geriatrics, Index of Coexistent Diseases, Kaplan, Geriatric Index of Comorbidity (GIC), and Chronic Disease Score--to predict adverse outcomes after discharge (1-year risk of rehospitalization, institutionalization, and death). Prospective study with 1-year follow-up, between January 2004 and December 2005 in 444 elderly patients (mean age, 85; 74% female) discharged from acute geriatric hospital, Geneva University Hospitals. In univariate analyses, Cumulative Illness Rating Scale?Geriatrics and GIC were the predictors with the largest coefficient of determination for mortality with (R(2) of 9.3%, respectively 8.8%). GIC was also the only significant predictor of institutionalization (R(2) = 6.0%). Higher risk of readmission was significantly associated with GIC (R(2) = 14.0%), Cumulative Illness Rating Scale-Geriatrics (R(2) = 5.6%), Charlson Comorbidity Index (R(2) = 3.1%), and Chronic Disease Score (R(2) = 1.7). Understanding how to efficiently predict these adverse outcomes in hospitalized elders is important for a variety of clinical and policy reasons. GIC and Cumulative Illness Rating Scale-Geriatrics may improve hospital discharge planning in a geriatric hospital treating very old patients with acute disease.