Diagnostic Concordance and Misclassification of Pre‐Eclampsia in a Malaria‐Endemic Setting: A Comparative Cross‐Sectional Study

Background
In malaria-endemic settings, overlapping clinical features between malaria and pre-eclampsia complicate accurate diagnosis of pre-eclampsia during routine antenatal care. Misclassification may delay initiation of appropriate management or lead to unnecessary interventions. This study evaluated diagnostic concordance between routine clinical assessment and predefined reference criteria and examined the contribution of malaria to diagnostic discordance.

Methods
A cross-sectional study was conducted amongst 618 pregnant women clinically diagnosed with malaria, pre-eclampsia or both across primary, secondary and tertiary health facilities. Routine diagnoses were compared with reference classification based on predefined criteria. Diagnostic concordance was assessed using χ2 testing and Cohen′s kappa coefficient. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the routine detection of pre-eclampsia were calculated. Multivariable linear and logistic regression analyses were performed to evaluate associations between log-transformed parasite density and diagnostic misclassification.

Results
Overall concordance between routine and reference classification was 50.2% (κ = 0.233, p < 0.001). Routine diagnosis of pre-eclampsia demonstrated a sensitivity of 61.8% and specificity of 62.2%, with a PPV of 65.9% and an NPV of 57.9%. Malaria parasite density was not independently associated with systolic or diastolic blood pressure but was associated with higher ln(uPCR) (β = 0.17, p < 0.001). Malaria parasite density was not an independent predictor of diagnostic discordance.

Conclusion
Routine diagnosis of pre-eclampsia in malaria-endemic settings demonstrates moderate diagnostic performance, with considerable misclassification, particularly in the presence of concurrent malaria.