Non-steroidal anti-inflammatory drug prescribing patterns in general practice: comparison of a general practitioner-based survey and a pharmacy-basedsurvey in France

Purpose In order to assess biases occurring in primary care prescription st udies, we compared non-steroidal anti-inflammatory drug (NSAID) prescribing patterns reported by general practitioners directly (GP-based survey) and from a pharmacy-based survey of general practitioner prescribing (pharmacy- based survey). Methods Volunteer GPs of the administrative area of Cote d'Or (France) retu rned a mailed questionnaire on NSAID prescribing patterns for consecutive p atients seen during a 2-month period. In order to obtain a reference basis, pharmacies of the same administrative area provided all prescriptions: tha t included NSAIDs during a 1-week period originating in general practice. Results The rate of participation was 25% for the GPs and 40% for the pharm acies. Participant GPs were representative of GPs of the area with regard t o sex, year of graduation and practice area but pharmacies from rural areas were over-represented. The GP-based survey and the pharmacy-based survey p rovided respectively 770 and 1050 prescriptions. There were no differences between either survey in the type of NSAIDs prescribed and in the most freq uently associated drugs. GPs who volunteered in the GP survey prescribed NS AIDs more frequently orally and at higher doses than GPs involved in the ph armacy-based survey. They also prescribed more gastroprotective drugs, espe cially in the elderly. None of these results could be explained by differen ces in patient characteristics and GP practice areas. Conclusion GPs who actively participate in prescription surveys exhibit pre scribing patterns that fit better with official recommendations than the av erage. Although selection biases cannot be ruled out, it is suggested that some changes in GP prescription habits may have been induced by the survey itself. Copyright (C) 2001 John Wiley & Sons, Ltd.