[Factors affecting drug expenditure in the primary care centre in a health area]

To identify the factors affecting drug expenditure.Design. Cross-sectional study.Setting. Madrid Primary Care area.

21 health centres.

Association of the drug expenditure per inhabitant of each health centre during 1999 with the characteristics of its staff and operation of the centre.

Expenditure on drugs per inhabitant, 14360 plus minus 3040 pesetas (86.31 plus minus 18.27; general practitioners, 19.62 plus minus 23.8%; doctors working as locums, 40.48 plus minus 20.72%; women doctors, 59.76 plus minus 13.36%; family doctors, 38.57 plus minus 21.35%; team nurses, 86.6 plus minus 18.27%; population over 65, 18.03 plus minus 7.73%; patients per day attended by each general practitioner, 32.82 plus minus 3.81; number of sessions per year on prescription profiles, 5 plus minus 3.91; prescription avoidable because of health card: 3106 plus minus 808 pesetas (18.67 plus minus 4.86 ); compliance with service offer, 1.7 plus minus 3.78. Drug expenditure per inhabitant dropped when sessions on prescription profiles (p = 0.013), the percentage of women doctors (p = 0.067) and the percentage of family doctors (p = 0.035) increased; and it dropped too when the over-65 population (p = 0.099) and the amount of prescription avoidable through the card (p = 0.034) dropped. In the multivariate analysis, the sessions on prescription profiles (ss = -843), the percentage of nurses in the reformed model (ss = -155), the percentage of family doctors (ss = -142) and the percentage of doctors from the traditional model (ss = -121) explain 71.2% of the variability in drug expenditure per inhabitant (F = 6.909; p = 0.002).

The sessions to discuss prescription profiles, the presence of nurses from the reform model, postgraduate medical training and the employment of doctors under the traditional model are the factors that our study finds are linked to lower drug expenditure per inhabitant.