Determinants of relapse and delayed convalescence in patients with Brucellosis: a one-year prospective follow-up.

BACKGROUND: Brucellosis is a globally occurring zoonotic infectious disease that causes severe illness in both humans and farm animals. AIMS: This study aimed to investigate the factors associated with relapse and delayed convalescence in patients with brucellosis. METHODS: This prospective, single-center study included patients diagnosed with brucellosis who presented to our clinic between January 2022 and January 2023. Patients were categorized into two groups based on relapse (- / +) and delayed convalescence (- / +). Clinical and laboratory findings were compared between the two groups. RESULTS: Of these 101 patients, 58.4% (n = 59) were male, and the mean age was 41.8 ± 14.6 years. Relapse occurred in 16 patients (15.8%). Relapse was observed in 68.7% (n = 11/16) of the patients in the first 6 months. In patients with relapse, smoking (p = 0.008, OR = 8.24, 95% CI:1.71-39.5), headache (p = 0.04, OR = 4.93, 95% CI:1.07-22.7) and increased lymphocyte percentage (> 48) (p = 0.004, OR = 11.9, 95% CI:2.21-64.7) were independent predictors associated with relapse. Delayed convalescence was observed in 17 of 85 patients (20%) who received successful treatment. Myalgia (100.0% vs. 76.5%, p = 0.026) and increased lymphocyte percentage (> 48) (23.5% vs. 7.4%, p = 0.048) were more common in patients with delayed convalescence than in those without. However, these parameters were not significant in multivariate analysis. CONCLUSIONS: Brucellosis patients who smoking, experience headaches, and have a lymphocyte count above 48% should be monitored for at least 6 months after treatment to assess the risk of relaps. It is important to note that symptoms may not completely resolve after treatment in patients with a lymphocyte count above 48% and myalgia.