Incidence and Warning Signs for Complications of Human Brucellosis: A Multi-center Observational Study from China

Abstract

Abstract background Brucellosis is one of the most serious “ignored zoonoses” in the world and especially affects poverty-stricken nations. Early diagnosis of focal complications in brucellosis increases treatment success. However, up to now, no clear joint indicators of symptoms or biomarkers for the diagnosis of complications. Hence, we investigated the warning signs of focal complications in human brucellosis aimed to provide practical parameters for clinicians in patients diagnosis and management. Methods A multi‑center cross‑sectional study was conducted in China from December 2019 to August 2021. The clinical characteristics and complications of brucellosis patients were based on questionnaire survey and medical record system. Warning signs of complications were assessed by univariate and multivariate logistic regression models. Receiver operating characteristic (ROC) curves and the area under the curve (AUC) were used for variable screening and model evaluation. Results A total of 880 participants of human brucellosis were enrolled. Of the patients, median age was 50 years [interquartile range (IQR):41.5,58.0] and 54.8% had complications. The complication involved any organ, common in osteoarticular system (43.1%), including peripheral arthritis (30.0%), spondylitis (16.6%), paravertebral abscess (5.0%) and sacroiliitis (2.7%); followed by genitourinary system (4.7%), respiratory system (4.7%), and hematologic system (4.6%). Long delay in diagnosis [odds ratio (OR):3.963, 95% confidence interval (CI):1.906–8.238 for > 90days], underlying disease(OR:1.675, 95%CI:1.176–2.384), arthralgia(OR:3.197, 95%CI:1.986–5.148), bulging pain(OR:3.482, 95%CI:1.349–8.988), C-reactive protein (CRP) > 10 mg/L (OR:1.910, 95%CI:1.310–2.784)and erythrocyte sedimentation rate (ESR) elevation (OR:1.663, 95%CI:1.145–2.415)were the relevant factors for focal brucellosis. The optimal cutoff value in ROC analysis was > 5.4 mg/L for CRP (sensitivity 73.4% and specificity 51.9%) and > 25 mm/h for ESR (sensitivity 47.9% and specificity 71.1%). Conclusions Over half of brucellosis patients suffered complications. Diagnostic delay, underlying disease, arthralgia, bulging pain, and high CRP and ESR were significant relevant markers of complications. Regardless of culture results and standard tube agglutination test (SAT) titers, patients with these conditions should be on the alert for complications.