Economic costs and benefits of treating mild hypertension: results from a cross-sectional model

Abstract

The economic value of treating mild hypertension in New Zealand was analysed using computer-based models which compared the major costs and benefits of treatment for 1 year in a notional population (n = 250,000) comprising equal numbers of middle-aged (45-65 yr) and elderly (greater than 65 yr) patients. The costs were those of the drugs and medical charges plus those of incidental illness in life years added by treatment. The benefits were increased productive output obtained by lower mortality and savings due to stroke treatment avoided in treated patients. Calculations were based on the age-specific risks attributable to hypertension found in observational studies, and on the actual benefits of treatment found in two clinical studies. Two models were studied. In model 1, not all hypertensive patients are diagnosed and not all treated patients are at risk. There was a large net cost with all measures of risk and/or benefit, varying from $80.5 m to $40.0 m. Model 2 assumed that all and only patients with hypertension are treated, and the corresponding figures were $71.4 m to -$9.6 m (ie, net benefit of $9.6 m), respectively. The net benefit was obtained only at the highest values of risk and risk reversal, and was due mainly to increased productive output in treated patients. Models were also sensitive to other factors such as altered drug costs. Calculation of the net cost of treating hypertension requires accurate evaluation of the attributable risk.