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

https://doi.org/10.1016/j.jamda.2010.11.011Get rights and content

Abstract

Background

Older patients often suffer from multiple comorbid conditions. Few comorbidity indices are valid and reliable in the elderly and were rarely compared.

Objective

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).

Design, setting, and participants

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.

Results

In univariate analyses, Cumulative Illness Rating Scale?Geriatrics and GIC were the predictors with the largest coefficient of determination for mortality with (R2 of 9.3%, respectively 8.8%). GIC was also the only significant predictor of institutionalization (R2 = 6.0%). Higher risk of readmission was significantly associated with GIC (R2 = 14.0%), Cumulative Illness Rating Scale–Geriatrics (R2 = 5.6%), Charlson Comorbidity Index (R2 = 3.1%), and Chronic Disease Score (R2 = 1.7).

Conclusions

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.

Section snippets

Patients and Data Collection

We carried out a prospective study in a 300–acute bed geriatric hospital (HOGER) where 22.7% were direct admission from the community, 54.0% were referred by the emergency unit, and 23.3% were transferred from other divisions of Geneva University Hospitals, Switzerland. Patients and data collection have been described elsewhere.16, 17, 18 Briefly, a representative sample of all patients aged 75 years and older, consecutively admitted between January 2004 and December 2005 were selected by

Characteristics of Participants

Of the 1854 eligible patients, 556 were randomized, 523 were successfully enrolled, and 496 survived to hospital discharge (27 died during the hospitalization). The 1-year follow-up was not done in 52 patients (10.5%): 12 patients had moved abroad from Switzerland and the assessment was refused in 30 cases by the patient and in 10 cases by the family. Then 444 patients were successfully followed for 12 months and had full data for these analyses (mean age 85.3 ± 6.7; 74% women). Table 2

Discussion

This article examines the relationship between a variety of comorbidity indices and a number of health outcomes (rehospitalization, institutionalization, and death) in hospitalized elderly. Of the 6 indices, the GIC explained the greatest amount of variability of 2 of the studied outcomes in univariate analysis, and its scores alone were the only ones associated with institutionalization. One of the main strengths of this study was the prospective, comprehensive assessment of the presence and

Acknowledgments

We thank the teams of Mrs. O. Baumer, L. Humblot, and M. Cos for technical assistance.

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    This work was supported by grants from the Swiss National Science Foundation (SNF) (3200B0–102069) and from the Swiss Foundation for Ageing Research (AETAS).

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