This study examined the moderating effect of caregiver burden on the relationship between patients' health status and institutional costs in Alzheimer disease (AD). Data were obtained on whether 421 community-dwelling patients with AD in the CATIE-AD trial received institutional services in the month preceding baseline and at 3-month, 6-month, and 9-month follow-up. All participants had a caregiver who lived with or visited them regularly. Outcome variables include hospital, nursing home, residential, and combined institutional costs. Mixed models were employed to estimate the interaction of Health Utility Index (HUI)-III scores (a health status measure) and 5 measures of caregiver burden. Wherever significant, results indicate that greater caregiver burden weakens the inverse relationship between health utilities and institutional costs, leading to greater costs than would be expected at a given level of health. Altogether 45.0% of the models (9/20) showed this effect (positive coefficient on the burden-HUI interaction term). Interventions to support caregivers should be based on caregiver burden, regardless of care recipient health status, for even seemingly manageable patients may be at heightened risk for institutionalization if caregivers experience sufficiently high levels of burden.
*Department of Gerontology and Gerontology Institute, McCormack Graduate School of Policy Studies, University of Massachusetts, Boston, MA
†Departments of Psychiatry and Epidemiology and Public Health, Yale University School of Medicine, New Haven
§Departments of Psychiatry, Neurology, and Gerontology, University of Southern California Keck School of Medicine, Los Angeles, CA
‡New England Mental Illness, Research, Education, and Clinical Center, VA Connecticut System, West Haven, CT.
Funding sources: This study was supported by a grant (N01 MH9001) from the NIMH, in addition to a grant from Wyeth Research, Philadelphia, PA.
Disclosures: E.A.M.: Has no disclosures to report. R.A.R.: Has received research support from Eli Lilly, Janssen Pharmaceutica, Astra-Zeneca, and Wyeth Pharmaceuticals. He has been a consultant to GlaxoSmithKline, Bristol Myers Squibb, Organon, and Janssen Pharmaceutica. He provided expert testimony for the plaintiffs in UFCW Local 1776 and Participating Employers Health and Welfare Fund, et al v. Eli Lilly and Company; for the respondent in Eli Lilly Canada versus Novapharm and Minister of Health, respondent; and for the Patent Medicines Prices Review Board. Canada, in the matter of Janssen Ortho Inc. and “Risperdal Consta.” L.S.S.: Has received research support from Astra-Zeneca, Bristol Myers Squibb, Eli Lilly, Johnson and Johnson, and Pfizer; and has been a consultant to Astra-Zeneca, Bristol Myers Squibb, Forest Laboratories, Johnson and Johnson, Lundbeck, Merz, and Pfizer, all manufacturers of antipsychotics and antidepressants related to CATIE-AD. He has served as an expert witness in litigation involving these drugs. He has been a consultant to Wyeth.
Reprints: Edward Alan Miller, PhD, MPA, Department of Gerontology, University of Massachusetts Boston, 100 Morrissey Boulevard., Boston, Massachusetts 02125 (e-mail: firstname.lastname@example.org).
Received September 24, 2009
Accepted May 25, 2010