Factors Associated with Chronic Chikungunya in Vitória, Espírito Santo State, Brazil, Between 2016 and 2020

Chikungunya patients may develop chronic joint pain that can persist for months to years. This study aimed to determine the factors associated with Chikungunya chronicity. This case-control study involved data from patients with laboratory-confirmed Chikungunya reported from March 2016 to December 2020 in Vitória, Espírito Santo state, Brazil. The data were accessed from compulsory notification databases (SINAN and eSUS VS) and electronic medical reports (Rede Bem-Estar). For each patient who developed chronic symptoms, we included a control patient who did not develop chronic symptoms by random sampling. A total of 183 chronic and 183 non-chronic patients were included in the study. Most of them were female (73.2%), with a median age of 49.5 years (interquartile range = 37-61), and presented fever (89.6%), myalgia (89.6%), arthralgia (89.3%), and headache (82.0%). Chronic patients were older (median = 53; interquartile range = 41-61) than non-chronic cases (median = 46; interquartile age = 31-61) (OR = 0.979, 95% CI = 0.968-0.991) and more frequently presented nausea (58.5% vs. 40.4%; OR = 2.109, 95% CI = 1.374-3.238), and leukopenia (20.2% vs. 10.9%; OR = 2.060, 95% CI = 1.122-3.779). Therefore, these characteristics should be monitored for the better clinical management of cases prone to chronicity.