The measurement of drug consumption

Summary

The consumption of insulin and oral antidiabetic drugs was measured at the gross sales level in Sweden and Norway and at the prescription level in Northern Ireland. “Agreed daily doses” were used as units of comparison, which defined as follows: insulin 40 I.U., tolbutamide 1 g, acetohexamide 500 mg etc. Consumption was expressed as the number of “agreed daily doses” per 1,000 inhabitants per day. This provided a rough estimate of the number of subjects for whom the drug had been prescribed per 1,000 population. The data were collected during the three months April – June 1971. Marked differences in the consumption of antidiabetic drugs were found between the three countries and also between areas within each country. The consumption of insulin was similar in Norway and Northern Ireland (3.5 and 3.9 agreed daily doses per 1,000 inhabitants per day), but almost twice as high in Sweden. In Norway much lower use was found in certain rural areas. The variation in the consumption of oral antidiabetic drugs was even more marked. Surprisingly, consumption was considerably higher in Sweden (15.8) than in the nearby Norway (7.3), and was even lower in Northern Ireland (4.3). The major use was of sulphonylureas, especially chlorpropamide. Within the countries there was marked regional variation in the choice of individual biguanides and sulphonylureas. The data are discussed in relation to such factors as the incidence of diabetes, the sole use of dietary treatment etc. It is concluded that studies in depth, which link the actual use of drugs by patients to diagnosis, diabetic symptoms and clinical outcome of treatment are necessary in order to explore the reasons behind the marked geographical differences and to define a rational drug policy. However, the methods described in the study may be used for early detection of gross national differences in drug utilization, the further investigation of which may reveal to be of great public health interest.