Primary care physicians' adoption of new drugs is not associated with their clinical interests: a pharmacoepidemiologic study.

OBJECTIVES. Increasing drug expenditures call for better understanding of the reasons behind individual general practitioners' (GPs') prescribing decisions. The aim was to analyse associations between GPs' clinical interests and their preference for new drugs. DESIGN. Historical cohort study using population-based prescription data and data collected by postal questionnaire. SETTING AND SUBJECTS. A total of 68 single-handed GPs in the County of Funen, Denmark. Main outcome measures. GPs' preferences for two new (2004) drug groups (selective cyclo-oxygenase-2 inhibitors and angiotensin-II antagonists) were analysed. The preference was defined as the percentage of patients receiving a new drug among first-time users of either the new drug or an older alternative. The GPs' preference proportion was modelled using linear regression analysis. Data from a questionnaire on GPs' interest in corresponding clinical areas (musculoskeletal diseases and hypertension, respectively), continuing medical education (CME) activities, and previous employment were the independent variables. RESULTS. The adjusted mean difference in preference for new drugs between GPs with high and low interest in each of the two clinical areas was 0.4% (95% CI -2.0% to 2.8%), and -2.2% (-15.0% to 10.7%), respectively. Only current CME activities in the area of hypertension were significantly associated with GPs' preference for new drugs (adjusted mean difference 17.9% (95% CI 5.8% to 30.0%). CONCLUSION. No clear association between GPs' self-rated clinical interest and their prescribing of new drugs was found.

Clinical interest: a study of the influence on general practitioners' prescribing.

PURPOSE: To analyse the association between general practitioners' clinical interest and prescribing rates in four clinical areas: dyspepsia, depression, headache and diabetes. METHODS: Data concerning general practitioners' prescribing during 2004 were retrieved from a pharmacy database and linked with data from a physician questionnaire and the National Health Insurance Register. To counterbalance differences in practice populations all 1-year prevalences of prescribing were standardised according to age and gender. Participants were asked 'To what extent do you find the following areas interesting from a professional point-of- view?' Four rating categories were used. The association between clinical interest and standardised prescribing rates was investigated using logistic regression, the Kruskal-Wallis test and a trend test. RESULTS: A total of 68 (72%) single-handed general practitioners representative of the total group completed the questionnaire. We observed a two-fold ratio between the 90% and the 10% percentiles of the 1-year prevalences of antisecretory drugs, antidepressants, migraine drugs as well as anti-diabetics. The variation in prescribing of antidepressant and antisecretory drugs was far above chance level. No significant association with clinical interest could, however, be observed for any of the four clinical areas. CONCLUSION: General practitioners' prescribing of the four classes of medical drugs varied considerably. However, only part of this variation was based on chance. This study did not confirm our hypothesis that general practitioners' level of clinical interest in one area corresponds with their prescribing of drugs used within that area.

General practitioners' adoption of new drugs and previous prescribing of drugs belonging to the same therapeutic class: a pharmacoepidemiological study.

AIM: To test the hypothesis that general practitioners (GPs) with high prescribing levels of certain drugs will adopt new drugs belonging to the same therapeutic group faster than those with low prescribing levels. METHODS: The adoption of four new drugs: esomeprazol, selective cyclo-oxygenase-2 inhibitors, new triptans, and angiotensin-II receptor blockers were analysed using population-based prescription data. We used the preference proportion (prescriptions for new rather than older alternatives for the same indication) to measure GPs' adoption rate. Annual prescribing volume and prevalence were used to measure previous prescribing of older drug alternatives. We modelled the preference proportion using multiple linear regression analysis and the prescribing of older drugs as independent variables. We controlled for the GPs' general prescribing level and weighted for practice size. In the first three analyses, we dichotomized data using the median, lower and upper quartile as cut-off point. Next, we grouped data into quartiles and finally, we used continuous data. RESULTS: For esomeprazol and new triptans there was a higher preference for new drugs among "high prescribers", but only when this term was defined as the upper quarter and the upper half of previous prescribing levels, respectively (mean difference in preference proportion: 10.2% (99% confidence interval = 1.3%, 19.1%) and 8.2% (0.2%, 16.2%)). For the remaining two drug classes the associations were weak and almost all statistically nonsignificant. CONCLUSION: There is no consistent association between GPs' level of drug prescribing and their adoption of new drugs of the same therapeutic group.

Does the early adopter of drugs exist? A population-based study of general practitioners' prescribing of new drugs.

OBJECTIVE: To analyse associations between indicators for adoption of new drugs and to test the hypothesis that physicians' early adoption of new drugs is a personal trait independent of drug groups. METHODS: In a population-based cohort study using register data, we analysed the prescribing of new drugs by Danish general practitioners. Angiotensin-II antagonists, triptans, selective cyclo-oxygenase-2 antagonists and esomeprazol were used in the assessment. As indicators of new drug uptake, we used adoption time, cumulative incidence, preference proportion, incidence rate and prescription cost and volume. For each measure, we ranked the general practices. Ranks were pair-wise plotted, and Pearson's correlation coefficient ( r) was calculated. Next, we analysed the correlation between ranks across different drug classes. RESULTS: For all indicators, the general practitioners' adoption of one group of drugs was poorly associated with adoption of others ( r