Epidemiology of tuberculous lymphadenitis in Africa: A systematic review and meta-analysis

Tuberculous lymphadenitis is the most frequent form of extra-pulmonary TB (EPTB) and accounts for a considerable proportion of all EPTB cases. We conducted a systematic review of articles that described the epidemiological features of TBLN in Africa.

Any article that characterized TBLN cases with respect to demographic, exposure and clinical features were included. Article search was restricted to African countries and those published in English language irrespective of publication year. The articles were retrieved from the electronic database of PubMed, Scopus, Cochrane library and Lens.org. Random effect pooled prevalence with 95% CI was computed based on Dersimonian and Laird method. To stabilize the variance, Freeman-Tukey double arcsine root transformation was done. The data were analyzed using Stata 14.

Of the total 833 articles retrieved, twenty-eight articles from 12 African countries fulfilled the eligibility criteria. A total of 6746 TBLN cases were identified. The majority of the cases, 4762 (70.6%) were from Ethiopia. Over 77% and 88% of identified TBLN were cervical in type and naïve to TB drugs. Among the total number of TBLN cases, 53% were female, 68% were in the age range of 15-44 years, 52% had a history of livestock exposure, 46% had a history of consuming raw milk/meat and 24% had history of BCG vaccination. The proportion of TBLN/HIV co-infection was much lower in Ethiopia (21%) than in other African countries (73%) and the overall African estimate (52%). Fever was recorded in 45%, night sweating in 55%, weight loss in 62% and cough for longer than two weeks in 32% of the TBLN cases.

TBLN was more common in females than in males. The high prevalence of TBLN in Ethiopia did not show directional correlation with HIV. Population based prospective studies are warranted to better define the risk factors of TBLN in Africa.