Antipsychotic prescribing quality and ethnicity: a study of hospitalized patients in south east London.

A number of studies have shown qualitative and quantitative differences in prescribing of antipsychotics according to patient ethnicity. Black patients tend, for example, to be prescribed higher doses of antipsychotics than whites. Few studies have controlled for other factors which may influence prescribing practice and confound results. This study sought to determine whether or not ethnicity was associated with antipsychotic polypharmacy, high dosage and antipsychotic costs before and after adjustment for potential confounding. We approached inpatients on acute general psychiatry wards at the Maudsley, Bethlem and Lambeth hospitals in south east London. Prescription details were noted. Subjects were interviewed and social and clinical details were recorded. In all, data on 23 potential confounders were collected.A total of 210 patients were approached of whom 153 agreed to take part. Of the 23 potential confounders, only use of English as a first language and duration of illness differed significantly between blacks and whites. Categorical findings were adjusted for these factors and other potential confounders such as age and gender. Total antipsychotic daily dose was 82.2% of licensed maximum in blacks, and 77.2% in whites (p=0.48). Antipsychotic polypharmacy was seen in 23.2% of blacks and 16.9% of whites (adjusted odds ratio (OR) 1.11; 95% CI, 0.45-2.75). High dose (> 100% of maximum dose) antipsychotic regimens were prescribed to 15.9% of blacks and 16.9% of whites (adjusted OR, 0.71: 95% CI, 0.27-1.90). Mean monthly cost of treatment was significantly higher in blacks than whites (182.79 vs 143.08 British pound; p=0.02; adjusted OR (> 150 British pound/month), 2.45: 95% CI, 1.19-5.08). Prescribing quality was similar for blacks and whites. Black ethnicity was associated with significantly higher mean monthly medication costs.