Clinical spectrum and factors associated with Brucella epididymo-orchitis among male patients in a high-endemic region of Northwest China.

BACKGROUND AND

OBJECTIVES

BEO is a clinically important but often underrecognized localized manifestation of brucellosis in male patients, particularly in high-endemic pastoral regions. However, large-scale data describing its clinical spectrum and associated factors remain limited. This study aimed to characterize the epidemiological, clinical, and laboratory features of BEO among hospitalized male brucellosis patients in Northwest China and to explore clinical and laboratory factors associated with BEO.

METHODS

This retrospective cross-sectional study was conducted at the regional infectious disease hospital of Ningxia Hui Autonomous Region from January 2021 to December 2023. Male inpatients aged 16 years or older with laboratory-confirmed brucellosis were included. Patients were classified into BEO and non-BEO groups. Demographic, clinical, and laboratory data were extracted from medical records. Univariable analyses were performed to compare the two groups, and multivariable logistic regression was used to identify factors associated with BEO.

RESULTS

A total of 1,188 hospitalized male brucellosis patients were included, of whom 72 had clinically recognized and imaging-confirmed BEO, accounting for 6.06% of the study population. In univariable analyses, fatigue, lumbago, positive blood culture, platelet count, white blood cell count, ESR, and symptom duration differed between the BEO and non-BEO groups. In the multivariable model, fatigue (OR = 0.43, 95% CI: 0.23-0.81, p = 0.008), lumbago (OR = 0.41, 95% CI: 0.21-0.82, p = 0.011), white blood cell count (OR = 1.13, 95% CI: 1.02-1.25, p = 0.019), and positive blood culture (OR = 1.77, 95% CI: 1.03-3.04, p = 0.038) remained associated with BEO. Platelet count, ESR, and symptom duration were not statistically significant after adjustment.

CONCLUSION

In this study, BEO was identified in 6.06% of hospitalized male brucellosis patients, and was associated with lower frequencies of fatigue and lumbago, higher white blood cell count, and positive blood culture. These findings suggest that BEO may represent a distinct localized clinical phenotype rather than a simple extension of systemic or osteoarticular disease. The observed associations should not be interpreted as causal predictors. Prospective multicenter studies with standardized screening, detailed exposure assessment, and longitudinal follow-up are needed to clarify the true burden, mechanisms, and long-term outcomes of BEO.