Physician and patient characteristics associated with prescriptions and costs of drugs in the Lazio region of Italy

Objective Prescribing medications is one of the most important therapeutic activities of a general practitioner (GP) and the quality of such practices is a relevant issue. Our objective was to use regional administrative databases to assess the following: (a) the prevalence of prescription drug use by patient age and gender, (b) different GPs' prescription volumes and average drug expenditure, and (c) how GPs' socio-demographic variables may be considered as predictive factors in their prescribing practices.Methods An observational cross-sectional study was carried out in the primary care setting (GPs and paediatricians only) on drug utilization in the period 1st January-31st December 2007. Poisson regression models were run to estimate the incidence rate ratio (IRR) of prevalence adjusted by patients' age. Linear regression models (for GPs and paediatricians separately) were performed to test the possible association between average drug expenditure and physicians' characteristics.Results The overall prevalence of drug utilization was approximately 65% of the total population and this finding is coherent with other studies. Age was a predictive determinant of average drug expenditure that was significantly higher for the elderly. Younger physicians were more likely to prescribe medications, independent of the presence of any chronic condition in their beneficiaries. Female GPs, those practicing in a group and those practicing in central Rome had a higher average drug expenditure. Results for paediatricians showed that there was a very strong geographical effect that influenced average expenditure.Conclusions Prescribing decisions are subject to a myriad of external factors. The present study shows how physicians' characteristics might affect drug prescription in terms of prevalence of use, costs and consumption. Using regional administrative databases it has been possible to analyse the association between doctors' prescribing habits, their socio-demographic factors and characteristics of their catchments areas. However, the variability in age groups in terms of prevalence, consumption and expenditure suggests that a sophisticated method of analysis will be needed in order to implement strategies and interventions able to optimise resource use in the health care sector.