Open Access Research article

Establishing a composite endpoint for measuring the effectiveness of geriatric interventions based on older persons’ and informal caregivers’ preference weights: a vignette study

Cynthia S Hofman12*, Peter Makai1, Han Boter3, Bianca M Buurman4, Anton JM de Craen5, Marcel GM Olde Rikkert1, Rogier ART Donders2 and René JF Melis1

Author Affiliations

1 Department of Geriatric Medicine (HP 925), Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, Netherlands

2 Department for Health Evidence (HP133), Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, Netherlands

3 Department of Epidemiology (FA41), University of Groningen, University Medical Centre, Groningen, PO Box 30001, 9700 RB, Groningen, Netherlands

4 Department of Internal Medicine, Section of Geriatric Medicine (F4-108), Academic Medical Center, PO Box 22660, 1100 DD Amsterdam, Netherlands

5 Department of Gerontology and Geriatrics (C2-R), Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, Netherlands

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BMC Geriatrics 2014, 14:51  doi:10.1186/1471-2318-14-51

Published: 18 April 2014

Abstract

Background

The Older Persons and Informal Caregivers Survey Minimal Dataset’s (TOPICS-MDS) questionnaire which measures relevant outcomes for elderly people was successfully incorporated into over 60 research projects of the Dutch National Care for the Elderly Programme. A composite endpoint (CEP) for this instrument would be helpful to compare effectiveness of the various intervention projects. Therefore, our aim is to establish a CEP for the TOPICS-MDS questionnaire, based on the preferences of elderly persons and informal caregivers.

Methods

A vignette study was conducted with 200 persons (124 elderly and 76 informal caregivers) as raters. The vignettes described eight TOPICS-MDS outcomes of older persons (morbidity, functional limitations, emotional well-being, pain experience, cognitive functioning, social functioning, self-perceived health and self-perceived quality of life) and the raters assessed the general well-being (GWB) of these vignette cases on a numeric rating scale (0–10). Mixed linear regression analyses were used to derive the preference weights of the TOPICS-MDS outcomes (dependent variable: GWB scores; fixed factors: the eight outcomes; unstandardized coefficients: preference weights).

Results

The mixed regression model that combined the eight outcomes showed that the weights varied from 0.01 for social functioning to 0.16 for self-perceived health. A model that included “informal caregiver” showed that the interactions between this variable and each of the eight outcomes were not significant (p > 0.05).

Conclusion

A preference-weighted CEP for TOPICS-MDS questionnaire was established based on the preferences of older persons and informal caregivers. With this CEP optimal comparing the effectiveness of interventions in older persons can be realized.

Keywords:
Composite endpoint; Preference-weighted; Elderly persons; Informal caregivers; Effectiveness; Geriatric interventions