[Recruitment and selection of test subjects for scientific research in geriatrics: literature review and experiences of the Nijmegen NESTOR study].

The conduct of research in geriatric medicine differs from that in other medical specialties in a number of ways. In geriatric research it is almost impossible to study a large, homogeneous group of subjects, suffering solely from the problem to be studied. Moreover, measurements and questionnaires should be short, simple and not very troublesome. These differences are due to the heterogeneity of geriatric patients and the high prevalence of multimorbidity, often resulting in impaired physical, psychological and social performance. In this article a number of issues which are important for successful recruitment and selection of subjects for geriatric research are discussed. First, a review of relevant literature is given, and subsequently, experiences concerning recruitment and selection appreciated in the Nijmegen geriatric research programme' are described. This programme was part of the governmental Netherlands Programme for Research on Ageing (NESTOR). According to the literature the efficacy of recruitment may be improved by: personal contact between researcher and subject in view, introduction of the selection criteria already at the time of subjects' recruitment, a balance between research burden and profit, sufficient rewards for participation, both financially and non-financially, maximal effort in the subjects' transport, and also piloting of the recruitment procedure. In the NESTOR-studies the average number of subjects who were recruited and who completed the studies was low (23%), because a lot of the recruited subjects did not meet the selection criteria or considered participation as too troublesome. Subjects who agreed to participate showed high research compliance.