Comparing cost-effectiveness analyses of anti-hypertensive drug therapy for decision making: mission impossible?

The purpose of this literature review was to compare the methodology used in the most recently published cost-effectiveness studies of antihypertensive treatments, and to identify methodological strengths and weaknesses that indicate the study's potential as a useful, decision-making tool. Based on the results of a search of several databases, spanning the years 1995 to 2000, 10 cost-effectiveness studies were identified. Although the majority of the studies reported their cost-effectiveness ratio in "costs per year of life gained," the studies also considered a varying range of components including additional end points. The methodology used to measure effectiveness, the cost variables included, and the characteristics of the patient population varied significantly across studies. Due to this lack of conformity, it would be difficult, if not impossible, to compare the results and draw conclusions about the relative cost-effectiveness of different types of antihypertensive drug therapies. This lack of uniform comparison across studies is likely to draw criticism from both the clinical and health-care decision-making communities. Future studies within this field should be thorough and useful for decision making. It is suggested that short-term outcomes should include systolic and diastolic blood pressure measurements and long-term outcomes should include end points such as myocardial infarction, stroke, congestive heart failure and renal events. Other positive outcomes such as a more favorable side-effect profile, should be used to enhance the primary outcomes. Additionally, when subpopulations are considered in submodels, studies should address the issue of generalizability. Cost calculations should be transparent and related to the perspective of the study. Modeling the cost-effectiveness of a drug may be an acceptable method provided that data sources and assumptions are valid and transparent.