Box 45.1Example of Country-specific Analysis: South Africa

In another analysis, researchers (Gaziano and others 2005) compared the approach based on absolute risk with blood pressure guidelines in South Africa. The analysis used country-specific epidemiology and, where available, applied local cost data. The study compared six strategies for initiating drug treatment—two different blood pressure levels (160/95 mmHg and 140/90 mmHg) and four different levels of absolute CVD risk over 10 years (40, 30, 20, and 15 percent)—to a strategy of no treatment. The methodology differed from the WHO-CHOICE study because of the availability of local data. Data on diabetes prevalence were included to further refine risk estimates. Also the actual mix of medications was used to assess costs with actual current drug-use patterns, which included the use of some nongeneric medications.

The table displays the results. The four absolute-risk strategies had the four lowest incremental cost-effectiveness ratios. The strategy of initiating antihypertensive therapy for those individuals with a predicted 10-year CVD risk greater than 40 percent had an incremental cost-effectiveness ratio of US$700 per QALY gained compared with no treatment. The absolute risk of CVD greater than 30, 20, and 15 percent had larger and increasing cost-effectiveness ratios. Treatments based on the 1995 South African guidelines and the Joint National Commission VI guidelines were both more costly and resulted in fewer QALY gains than the 15 percent absolute-risk strategy and were therefore dominated by the less costly absolute-risk treatment strategies.

Furthermore, the results showed that the cost-effectiveness ratios were quite sensitive to the costs of treatment for hypertension, especially medication costs. Further analysis revealed a threshold point for an annual treatment cost of US$53. Below this threshold, the 40 percent absolute-risk strategy cost less and increased the number of life years gained compared with the no primary prevention strategy and is therefore cost saving. In South Africa, annual treatment with diuretics and beta-blockers could be provided for less than US$40.

Incremental Cost-Effectiveness Ratios for Selected Hypertension Management Strategies over 10 Years, South Africa

Incremental cost-effectiveness ratioa
TreatmentUS$/QALYUS$/life year savedb
No treatmentn.a.n.a.
Absolute risk of CVD > 40 percent700900
Absolute risk of CVD > 30 percent1,6002,100
Absolute risk of CVD > 20 percent4,9006,700
Absolute risk of CVD > 15 percent11,00018,000
Target level 160/95 mmHg (1995 South African guidelines)DominateddDominatedd
Target level 140/90 mmHg (Joint National Commission VI guidelines)cDominateddDominatedd

n.a. = not applicable.

a. Each strategy's costs and effects are compared with those of the preceding less costly strategy.

b. Total and incremental life years not shown.

c. Compared with an absolute risk of CVD greater than 15 percent because the 1995 South African guidelines are dominated by the former.

d. A dominated strategy is one that is both more expensive and less effective than the preceding strategy to which it is compared.

From: Chapter 45, The Growing Burden of Risk from High Blood Pressure, Cholesterol, and Bodyweight

Cover of Disease Control Priorities in Developing Countries
Disease Control Priorities in Developing Countries. 2nd edition.
Jamison DT, Breman JG, Measham AR, et al., editors.
Copyright © 2006, The International Bank for Reconstruction and Development/The World Bank Group.

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