Comparison of prescribing unit with index including both age and sex in assessing general practice prescribing costs.

Abstract

To examine and compare the prescribing unit and a new prescribing index adjusting for age and sex in assessing general practice prescribing. Analysis of all prescriptions issued by two practices in one year. Use of data to derive a prescribing index adjusting for age and sex. Comparison of effect of prescribing unit and new index on relation between 80 practices' prescribing data and family health services authority average. Newcastle and Gateshead Family Health Services Authorities. Two urban practices with eight doctors and combined list size of 16,300 patients. Cost and number of prescriptions issued to each age and sex group. Effect of index on relation between practice data and family health services authority average. The number of items prescribed and total costs rose with age. Although total costs were greater for women than for men, individual items cost more for men aged 25-84. Comparison of data adjusted by the prescribing unit and the new index with authority averages produced no significant differences except in a few practices with skewed age-sex demography. Results with the two indexes differed by over 5% in 34% (27/80) of practices for costs and in 14% (11/80) for items prescribed. The age and sex profile of a practice does not explain interpractice variation in prescribing patterns. Other unidentified factors need to be considered.