Individual cost effectiveness ratios were calculated for all 19 studies which were then combined in an ordinary least squares (OLS) regression analysis with cost effectiveness (CE) ratio as the dependent variable with age and diastolic blood pressure as the key explanatory variables.
Statistical tests were undertaken to ascertain whether any of these variables were significantly related to the CE ratios. The results focused on the effect of age with respect to cost effectiveness. Therefore, the author reported the regression coefficients for different analyses.
For men the average cost per life year gained decreased by SEK 16,000 every year of older age at treatment, whilst for women the equivalent was SEK 15,000. For men in 3 trials there were negative effects, 5 trials resulted in cost savings, and the maximum CE ratio was SEK 619,000. In women, 2 trials had negative effects, 2 trials were cost saving and the maximum CE ratio SEK 462,000.