Comparison of the association between disease burden and inappropriate medication use across three cohorts of older adults.

BACKGROUND

Use of potentially inappropriate medications is common in nursing facilities (NFs), in which frail older adults are particularly vulnerable to adverse drug effects. The community-dwelling elderly are generally healthier and have lower overall rates of medication use, but their prescribed medications are not subjected to the same degree of regulatory scrutiny as those of residents in NFs. Frail elderly (FE) adults who are nursing home eligible but are receiving home- and community-based services (HCBS) constitute a distinct group sharing a high disease burden and high levels of medication use with the NF population.

OBJECTIVE

The goal of this study was to examine the relationship between disease burden and inappropriate medication use in these 3 cohorts, with adjustment for demographic and clinical differences.

METHODS

We performed retrospective analyses of Medicaid claims data from May 2000 through April 2001 to identify 3 cohorts of Kansas Medicaid beneficiaries: community-dwelling older adults (the ambulatory cohort); persons receiving HCBS through the Kansas Frail Elderly Program (the FE cohort); and elderly NF residents (the NF cohort). Demographic, clinical, and medication data were extracted from the Medicaid claims data. Unconditionally inappropriate medications were identified using the 1997 Beers criteria. The Cumulative Illness Rating Scale for Geriatrics was used to calculate the disease burden sum, classified as 0 or 1, 2 or 3, 4 or 5, or > or =6 disease categories. Odds ratios for inappropriate medication use at each level of disease burden in each cohort were derived using multivariable models adjusted for demographic and clinical factors, including overall level of medication use.

RESULTS

The final sample included 3185 persons in the 3 cohorts (1163 ambulatory, 858 FE, 1164 NF). Inappropriate medication use was determined to have occurred in 21%, 48%, and 38% of the respective cohorts and was highest in FE cohort members with the greatest disease burden (61%). For the ambulatory and FE cohorts, inappropriate medication use rose as the disease burden increased. The same was not observed in the NF cohort, in whom rates of inappropriate medication use showed little variation regardless of disease burden.

CONCLUSIONS

The relationship between disease burden and inappropriate medication use varied by setting. Those members of the FE cohort with the highest disease burden had the greatest risk for inappropriate medication use.