Challenges in malaria diagnosis and treatment in Kinshasa Province, Democratic Republic of the Congo

BACKGROUND: Effective malaria case management relies on accurate diagnosis and appropriate treatment. However, rapid diagnostic test (RDT) performance varies, and presumptive treatment remains common. We quantified malaria misdiagnosis and inappropriate treatment and assessed adherence to treatment guidelines in a high-burden setting. METHODS: We leveraged samples collected during a cohort study of children and adults from 2015 to 2022 across seven sites in Kinshasa Province, Democratic Republic of the Congo (DRC). We estimated the cumulative incidence and prevalence of false-positive and false-negative RDT results using PCR as the gold standard and identified correlates of misdiagnosis and inappropriate treatment using Kaplan Meier and generalized estimating equations. RESULTS: Among 2,269 participants, the one-year cumulative incidences of false-positive and false-negative RDTs were 23.1% and 17.8%, respectively; by seven years, these rose to 77.7% and 83.4%. Misdiagnosis (false-positive or -negative RDT) was associated with age, recent treatment, transmission intensity, and parasite density -factors that could inform refinements to treatment guidelines. About 58% of RDT-negative participants received antimalarial treatment at a clinic visit, while 4% of RDT-positive participants did not. Fever significantly reduced adherence to test-and-treat guidelines. CONCLUSIONS: Most participants experienced malaria misdiagnosis by RDT over the course of the study, underscoring the limitations of currently used RDTs and opportunities for improved clinical decision-making. While RDTs remain essential for malaria case management, clinicians should consider contextual factors when interpreting results. Efforts to improve adherence to guidelines, which require a positive diagnostic test result before treatment, and management of non-malarial febrile illness are needed in the DRC and similar high-burden settings.