The rising expenditure on antihypertensive drugs in New Zealand, 1981-1987.

The rising cost of treating hypertension has become an issue of concern in several countries, including the United States, parts of Europe, and more recently, New Zealand. In New Zealand between 1981 and 1987, the total inflation-adjusted expenditure on antihypertensive drugs increased by 61.7%, from $21.4 million to $34.6 million in constant 1981 dollars. The major part (56.3%) of this increase in overall expenditure was explained by the rise in real cost of drug treatment, while the number of patients on drug therapy remained virtually static over the same period. The average cost of a prescription for hypertension was estimated to have risen by 46.1% between 1981 and 1987, i.e. from $7.30 to $10.66 in constant 1981 dollars. Pardoxically the mean inflation-adjusted price of antihypertensive drugs fell by 10.8% over the same period. Changing patterns of prescription and the entry of new drugs into the market accounted for most of the rise in average cost per prescription over the study period. Unless the rising expenditure can be justified by demonstrable improvements in treatment outcome, continuation of these trends will have profound effects on the cost-effectiveness of antihypertensive therapy.