Caregiver-specific outcomes in antidementia clinical drug trials: A systematic review and meta-analysis

OBJECTIVES: To describe the range of caregiver-specific outcomes and approaches to their study within antidementia drug trials and to quantify the effect of cholinesterase inhibitors on burden and active time use of caregivers of persons with Alzheimer's disease (AD). DESIGN: Systematic review of English-language publications and unpublished reports of antidementia clinical drug trials that included caregiver-specific outcomes. Study characteristics and methodological quality were summarized. Random effects meta-analyses were conducted for the outcomes of caregiver burden and active time use. SETTING: Community. PARTICIPANTS: Informal caregivers of participants in clinical trials of antidementia drugs. MEASUREMENTS: Burden, time use, psychological well-being, healthcare costs, and ease of use of or satisfaction with intervention. RESULTS: Seventeen studies involving 4,744 subjects were identified. Four trials (n = 1,594) met criteria for inclusion in the burden analysis, and six trials (n = 2,286) met criteria for inclusion in the time-use analysis. Most investigations involved drugs now approved by the Food and Drug Administration for the treatment of AD; donepezil was the most frequently studied intervention in the set of studies. Methodological quality varied across trials. The weighted average effect sizes were Cohen's d = 0.18 (95% confidence interval (CI) = 0.04-0.32) and d= 0.15 (95% CI = 0.07-0.24) for the outcomes of caregiver burden and time use, respectively. CONCLUSION: Cholinesterase inhibitors have a small beneficial effect on burden and active time use among caregivers of persons with AD. Recommendations to enhance the quality and interpretability of AD clinical trials that involve caregiver-specific outcomes are presented.