Pre-hospital time delays in imported malaria diagnosis in hospitalized sub-Saharan travelers and migrants: not only on the patient's shoulders.

Purpose: To analyze the diagnostic delay in malaria related to misdiagnosis at first medical visit and its association with the risk of severe malaria in non-endemic areas.

Methods: Retrospective observational study of sub-Saharan migrants with imported malaria from January-2010 to December-2022. Patients were allocated in two groups depending on if malaria was suspected at first medical visit or not. Time delays in seeking healthcare, medical diagnostic delay (time between first attending a medical facility and the diagnosis of malaria) and total diagnostic delay (time between the onset of symptoms and the diagnosis of malaria) were calculated.

Results: 297 patients were included in the analysis. At first medical visit, malaria was misdiagnosed in 137 patients (46.1%). Medical diagnostic delay and total diagnostic delay were larger for the misdiagnosis group than for those properly diagnosed at first visit (p < 0.001). Although time in seeking healthcare was shorter in the misdiagnosis group, the presence of suggesting symptoms, such as fever, was lower (p < 0.050). Misdiagnosis was more frequent in emergency rooms linked to primary healthcare (p < 0.001). For the overall population (n = 297), total diagnostic delay was mainly due to delay in seeking healthcare. Initial misdiagnosis was associated with a higher risk of severe malaria (adjusted OR 2.23 [1.09-5.10], p = 0.031).

Conclusion: In a non-endemic area with a high rate of imported malaria, the percentage of patients misdiagnosed is surprisingly high. Misdiagnosis is associated with longer medical and total diagnostic delays and with a higher risk of severe malaria. It seems necessary to redesign training programs to improve knowledge among healthcare professionals and actions targeted to travelers to promote seeking healthcare advice promptly.