Inappropriate medication use and transition to nursing home among community-dwelling elders

Abstract

Background. The objective of this observational study was to investigate the relationship between transitions from community to nursing home (NH) and inappropriate medication use in older adults. Specific aims were to estimate: (1) incidence of transitions from the community to NH; (2) prevalence of inappropriate medication use among community-dwelling elders; and (3) the association between transitions from the community to NH and inappropriate medication use. Methods. A retrospective cohort was assembled from a sample of elderly Medicare beneficiaries with employer-sponsored supplemental health insurance. A longitudinal data set was created from Medicare supplemental insurance claims at the person-month level. After an initial baseline year with no NH events, each subject was followed until the first month of NH transition, loss to follow-up or the end of the 24-month follow-up period. The exposure was a time-dependent variable defined as use of any one of twenty-two categories of drugs considered by experts to be inappropriate in the elderly. Survival analysis for interval-censored data was used to compare the hazard of NH transition among those with and without inappropriate drug use in the previous three months. Results. 487,383 subjects were eligible for inclusion. Mean age was 74 years; 56% were female. Annual prevalence of any inappropriate drug was 42%. NH incidence rate was 28.4 per 1,000 person-years. After adjustment for potential confounders, the use of any inappropriate drug was associated with a 31% increase in risk of transition, compared to no use of inappropriate drug, within the past three months (adjusted hazard ratio 1.31, 99% CI 1.26, 1.36). Analyses of individual drug classes showed the risk of nursing home transition was similar for inappropriate drugs and alternative drugs of the same class. Conclusion. Inappropriate drug use was associated with an increased risk of nursing home transition. However, findings suggest that the association may be confounded by indication. That is, it may not be the "inappropriateness" of the drug, but rather the indication for the drug itself, that increased the risk of NH transition. However, use of these medications may be a marker that could be used to identify people at risk for NH transition.