Abstract 13130: Primary Prevention of Acute Rheumatic Fever and Rheumatic Heart Disease with Penicillin in South African Children with Pharyngitis: A Cost-Effectiveness Analysis

Abstract

Introduction: Acute rheumatic fever (ARF) and subsequent rheumatic heart disease (RHD) remain a challenge in poor countries. Primary prevention has not been widely adopted due to health systems barriers and concern about its cost-effectiveness. Hypothesis: Using a clinical decision rule (CDR) is a cost-effective strategy to diagnose and treat children with pharyngitis to prevent ARF and RHD in South Africa.

Methods: We used a Markov model to calculate the differences in costs and benefits for each strategy: (1) empirical treatment with intramuscular (IM) penicillin (Treat All); (2) treatment based on a positive throat culture (Culture All); (3) treatment based on a CDR score of ≥ 2 (CDR 2+); (4) treatment based on a CDR score of ≥ 3 (CDR 3+); (5) treating those with a CDR score of ≥ 2, culturing those with CDR scores < 2, and treating positive cultures (CDR2+, Culture CDR negatives); (6) treating those with a CDR score of ≥ 3, culturing those with CDR scores < 3, and treating positive cultures (CDR3+, Culture CDR negatives); and (7) observation only (Treat None).Outcome was incremental cost-effectiveness ratios (ICERs) in US$ per quality-adjusted life year (QALY) gained.

Results: The Treat All strategy had the lowest average cost of $14.70 per case of pharyngitis, followed by the CDR 2+ strategy ($16.15); the CDR2+, Culture CDR negatives strategy ($19.57); the CDR3+, Culture CDR negatives strategy ($27.31); the CDR3+ strategy ($27.56); and the Culture All strategy ($31.01). Only the CDR2+, Culture CDR negatives strategy yielded more QALYs but with an ICER of $84,000/QALY compared to the Treat All strategy, well above the willingness to pay recommended by the WHO. All other strategies were less effective and more expensive. The results were sensitive to the prevalence of GAS across a range of 1.6% to 30%, to the probability of ARF in untreated GAS (0.3 to 5%), and to the risk of anaphylaxis from treatment (0 to 0.05%).

Conclusion: A strategy of treating all children who present with pharyngitis with IM penicillin in South Africa is the least costly strategy. A strategy of using a clinical decision rule plus culturing those who are not positive would increase life-expectancy but at a cost that may be prohibitive. A strategy of culturing all children costs more and saves fewer lives.