Using unemployment rates to predict prescribing trends in England.

BACKGROUND There are many factors underlying trends in prescribing levels in England. AIM This study set out to examine prescribing trends and their relationship with three measures of morbidity. METHOD A study was undertaken examining the interrelations between basic prescribing parameters for the 90 family health services authorities in England for the year 1 April 1989 to 31 March 1990. The trends were examined for their associations with three factors which have been linked to morbidity levels: standardized mortality ratios, the Jarman index (through its use as a deprivation index), and unemployment rates. RESULTS Analysis revealed a strong inverse association between the number of items prescribed per patient and the net ingredient cost per item for the family health services authorities. These two factors together determined the net ingredient cost per patient. Cluster analysis was found to segregate approximately the family health services authorities geographically: the northern, urban areas of England were characterized by a high number of low cost items per patient while the southern semi-rural areas had a low number of high cost items per patient. The trend was such that the former area had a higher overall net ingredient cost per patient. Unemployment rates were the most robust determinant of the inverse trend of number of items and cost of items and were comparable with standardized mortality ratios in their individual correlations with the prescribing net ingredient cost per patient. The Jarman index was the weakest of the predictors. CONCLUSION The results lend support to the argument that material deprivation, associated with unemployment, is an important determinant of prescribing trends, perhaps acting through its effect on morbidity, and that the Jarman index is a poor indicator of deprivation. The analysis alone cannot, however, determine cause and effect for the apparent relationship between unemployment and prescribing.