Some patterns of prescribing by urban general practitioners.

To detect the differences in patterns of prescribing between general practitioners with high and low costs, the costs in prescribing seven symptomatic and seven systematic drug groups were studied in 23 practices with low costs and 23 with high costs in the Belfast area. This was done by extracting information about the individual practices from the Department of Health and Social Services (Northern Ireland) information technology unit's database on prescribing. General practitioners in practices with high costs issued prescriptions more often and for larger quantities of medicine than did their colleagues in practices with low costs for all of the drug groups studied. There was a lower patient to doctor ratio in the practices with high costs (1786:1 v 2039:1). The prescribers with high costs offered more surgery sessions than their colleagues with low costs, amounting to an average of 6.5 extra surgery sessions per 1000 patients per month. Half as many more patients with heart disease, asthma, diabetes, and thyroid disease seemed to be treated by doctors in practices with high costs than in practices with low costs. A higher rate of prescribing symptomatic drugs by these same doctors was also seen, and further study is recommended in view of the risks associated with these drugs.