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

Brucellosis is a globally occurring zoonotic infectious disease that causes severe illness in both humans and farm animals.

This study aimed to investigate the factors associated with relapse and delayed convalescence in patients with brucellosis.

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.

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.

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.