Follow-up outcomes of asymptomatic brucellosis: a systematic review and meta-analysis

ABSTRACT

Balancing the potentially serious outcomes of asymptomatic brucellosis and “waiting” for treatment in clinical practice is an urgent issue. Therefore, we assessed the follow-up outcomes and epidemiological characteristics of asymptomatic brucellosis in the absence of treatment to provide evidence-based clinical clues. We searched eight databases in which 3610 studies from 1990 to 2021 were related to the follow-up outcomes of asymptomatic brucellosis. Thirteen studies, involving 107 cases, were finally included. Regarding the follow-up outcomes, we examined the presence or absence of symptoms and decreased serum agglutination test (SAT) titre. During the 0.5–18 months follow-up period, the pooled prevalence of appearing symptomatic was 15.4% (95% CI 2.1%–34.3%), cases that remained asymptomatic were 40.3% (95% CI 16.6%–65.8%), and decreased SAT titre was observed in 36.5% (95% CI 11.6%–66.1%). Subgroup analysis indicated that the pooled prevalence of appearing symptomatic with follow-up times of less than 6 months, 6–12 months, and 12–18 months was 11.5%, 26.4%, and 47.6%, respectively. The student subgroup had a higher prevalence of symptoms (46.6%) than the occupational and family populations. In conclusion, asymptomatic brucellosis has a high likelihood of appearing symptomatic and its severity may be underestimated. Active screening of occupational and family populations should be enhanced, and special attention should be paid to high-titre students for early intervention, if necessary. Additionally, future prospective, long-term, and large-sample follow-up studies are essential.

KEYWORDS:

• Brucellosis
• asymptomatic
• follow-up outcomes
• prevalence
• public health
• meta-analysis

Acknowledgments

We would like to thank all the participants for their support during the follow-up study, as well as the researchers who had published high-quality articles for our meta-analysis. Fande Li: methodology, software, formal analysis, writing-original draft; Lanping Du and Mujinyan Li: data curation, investigation, resources; Wenqi Fan, Hua Zhen and Shuqi An: formal analysis, roles-original draft; Meifang Zhao, Yuke Yan and Huixin Yang: formal analysis, visualization; Cui Zhang, Xin Han, Zhuo Li and Chao Guo: writing-review & editing; Qing Zhen: conceptualization, validation, supervision.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Availability of data and materials

All data generated or analyzed during this study are included in this published article and its supplementary files.

Additional information

Funding

This study was supported by a competitive grant from the Department of Science and Technology of Jilin Province (Project Number: 20191102007 YY).