[The stable patient collective as a potential pitfall of prospective primary health-care studies. A qualitative inquiry among general practitioners]. / Der feste Patientenstamm als potentielle Fallgrube prospektiver Studien im primärärztlichen Sektor: Eine qualitative Erhebung unter Studienhausärzten.

ABSTRACT

BACKGROUND AND PURPOSE: Transparency and disclosure of problems in primary health-care studies can add enormous information to the planning and conduction of such studies. By means of the inquiry of study participants, important data on study problems can be found out. Therefore, the aim of this qualitative study was to identify the causes of unexpected results of an intervention study in general practitioners' (GPs) practices by means of an inquiry of the participating GPs. The very study was about diagnosing alcohol- related health disorders at two points of time 1 year apart each with 2,400 primary health-care patients. METHODS: 39 of the 43 participating GPs of the study mentioned were asked by telephone about the possible causes of the unexpected study results. Data analysis was conducted according to the Qualitative Content Analysis of Philipp Mayring. RESULTS: The GPs mentioned problems that are already described in the international literature the high expenses for study documentation, tabooed health topics, and declining participation motivation at the end of the study. A further cause of the unexpected study results was picked up the repeated patient recruitment of this intervention study. It was unclear for the GPs whether they could include the same patients at the first and second recruitment point of time. Moreover, one main reason for the unexpected study results seems to be the stable patient collective of GPs' practices; according to that, only few new patients could be included at the second time point of recruitment. CONCLUSION: In primary health-care research requiring several time points for patient recruitment, one has to consider potential tabooed health topics and the special situation in primary health-care practices. This situation is characterized by a stable amount of known patients, even over years. The here-discussed causes of recruitment problems might be essential to avoid selection bias in primary health-care studies.