Does Introduction of Thresholds in Decision Aids Benefit the Patient? Comparison Between Findings-Based and Threshold-Based Diagnostic Decision Aids

Purpose: To assess how different diagnostic decision aids perform in terms of sensitivity, specificity, and harm. Methods: Four diagnostic decision aids were compared, as applied to a simulated patient population: a findings-based algorithm following a linear or branched pathway, a serial threshold–based strategy, and a parallel threshold–based strategy. Headache in immune-compromised HIV patients in a developing country was used as an example. Diagnoses included cryptococcal meningitis, cerebral toxoplasmosis, tuberculous meningitis, bacterial meningitis, and malaria. Data were derived from literature and expert opinion. Diagnostic strategies’ validity was assessed in terms of sensitivity, specificity, and harm related to mortality and morbidity. Sensitivity analyses and Monte Carlo simulation were performed. Results: The parallel threshold–based approach led to a sensitivity of 92% and a specificity of 65%. Sensitivities of the serial threshold–based approach and the branched and linear algorithms were ...