Long-term survival and clinical forms in the acute phase of Chikungunya virus infection in older Caribbeans

Abstract

Objective: To investigate whether the long-term survival in elderly patients with prior Chikungunya virus infection (CVI) is associated with the clinical form presented in the acute phase, as defined by the WHO classification. Methods: Retrospective cohort study performed in Martinique University Hospitals. Patients who attended the emergency department for suspected CVI, and who had a positive biological diagnosis of CVI by reverse transcription-polymerase chain reaction on a plasma sample between 10 January and 31 December 2014 were eligible for inclusion. Time-to-death was the primary outcome. The independent relationship between clinical forms and time-to-death was analysed using a Cox model. Results: In total, 268 patients were included. Mean age was 80 ± 8 years, 53% were women. Median length of follow-up was 28 months (range: 0–39). During follow-up, 53 (19.8%) patients died. Median survival time was 13.2 months (range: 0–33.6). At the end of follow-up, death rates were 4.6% for acute clinical cases, 19.0% for atypical cases, 19.2% for severe acute cases and 23.5% for unclassifiable cases. By multivariable analysis, the clinical form of CVI at admission was found to be independently associated with long-term survival (atypical form: HR = 2.38; 95% CI = 2.15–2.62; severe acute form: HR = 2.40; 95% CI = 2.17–2.64; unclassifiable form: HR = 2.28; 95% CI = 2.06–2.51). Conclusion: The clinical form at presentation with CVI has a significant impact on long-term survival. Management of CVI patients should be tailored according to their clinical form at admission.