A Framework for Evaluating Health System Surveillance Sensitivity to Support Public Health Decision-Making for Malaria Elimination: A Case Study from Indonesia

Abstract

Background: The effectiveness of a surveillance system to detect infections in the population is paramount when confirming elimination. Estimating the sensitivity of a health system requires identifying key steps in the cascade, from initial infection to confirmed diagnosis, and quantifying the probability of appropriate action at each stage. Using malaria as an example, a framework was developed to estimate the sensitivity of key components of the malaria surveillance cascade. Methods: Parameters to quantify the sensitivity of the surveillance system were derived from monthly malaria case data over a period of 36 months and semi-quantitative surveys in 46 health facilities on Java Island, Indonesia. Parameters were estimated by modelling the flow of an infected individual through the system and the underlying expected malaria cases in the population using autoregressive spatio-temporal models in a joint inferential Bayesian framework. A model-driven health system survey was designed to collect empirical data to inform parameter estimates in the surveillance cascade. Findings: Heterogeneity across health facilities was observed in the estimated probability of care-seeking (Range=0.012 - 0.191) and testing for malaria (Range=0.000 - 0.630). Care-seeking was higher at facilities regularly providing antimalarial drugs (odds ratio = 1.48, credible intervals: 1.47/1.48). Predictably, the availability of functioning microscopy equipment was associated with increased odds of being tested for malaria (odds ratio = 136.0, credible intervals = 92.08/199.30). Interpretation: Methods for estimating facility-level malaria surveillance sensitivity, particularly in areas targeting elimination, can help provide a benchmark and identify components of the health system that can be improved to strengthen surveillance to support public-health decision-making. Funding Information: This study was funded by the Bill and Melinda Gates Foundation (grant OPP1177272) awarded to GS and CD and by the Indonesia Endowment Fund for Education (Lembaga Pengelola Dana Pendidikan Indonesia; grant: 20151022084537) awarded to HS. Declaration of Interests: We declare no competing interests.