Inflammatory bowel disease in sub-Saharan Africa: epidemiology, risk factors, and challenges in diagnosis.

Over the past century, the incidence of inflammatory bowel disease (IBD) in high-income countries has shown a sharp rise that then plateaued, and a similar trend has been observed in newly industrialised countries. IBD has long been considered uncommon in sub-Saharan Africa, possibly reflecting low exposure to environmental risk factors described in high-income populations. Alternatively, individuals living in sub-Saharan Africa might have a different genetic disposition. However, some cases of IBD might remain undetected in sub-Saharan Africa because of a lack of awareness, deficiencies in diagnostic and clinical capacity, and a substantial rate of misdiagnosis due to the high burden of infectious diseases. There are few published data describing the natural history of IBD in sub-Saharan Africa, and the true burden of the disease remains largely unknown, although there is some evidence that the incidence of IBD is rising in this region. This Series paper summarises the present understanding of IBD and challenges facing clinicians when diagnosing this disease in sub-Saharan Africa.

Challenges in the management of inflammatory bowel disease in sub-Saharan Africa.

Inflammatory bowel disease (IBD) is generally considered a disease of high-income countries and is regarded as rare in sub-Saharan Africa. However, this assumption is almost certainly an underestimate, and the high burden of communicable diseases makes IBD in sub-Saharan Africa difficult to detect. Furthermore, some gastrointestinal infections can closely mimic IBD, contributing to delays in diagnosis and complicating therapeutic decision making. Constraints in endoscopic capacity alongside a scarcity of qualified diagnostic pathologists add to the difficulties. Implementing evidence-based guidelines recommended by international societies is challenging, mostly due to high costs and unavailability of medication. However, cost-effective approaches can still be implemented to manage IBD in sub-Saharan Africa as the predominant disease phenotype is mild-to-moderate ulcerative colitis, which often responds to treatment with basic medication. In this Series paper, we summarise the current management of IBD in sub-Saharan Africa and propose how it can be tailored to suit the epidemiological and socioeconomic specificities of the region. We also discuss measures required to address existing challenges, such as educating health-care workers about the diagnosis and management of IBD or improving endoscopic capacity.

Inflammatory bowel disease in sub-Saharan Africa: a protocol of a prospective registry with a nested case-control study.

INTRODUCTION: The epidemiology of inflammatory bowel disease (IBD) in sub-Saharan Africa is poorly documented. We have started a registry to determine the burden, phenotype, risk factors, disease course and outcomes of IBD in Zimbabwe. METHODS AND ANALYSIS: A prospective observational registry with a nested case-control study has been established at a tertiary hospital in Harare, Zimbabwe. The registry is recruiting confirmed IBD cases from the hospital, and other facilities throughout Zimbabwe. Demographic and clinical data are obtained at baseline, 6 months and annually. Two age and sex-matched non-IBD controls per case are recruited-a sibling or second-degree relative, and a randomly selected individual from the same neighbourhood. Cases and controls are interviewed for potential risk factors of IBD, and dietary intake using a food frequency questionnaire. Stool is collected for 16S rRNA-based microbiota profiling, and along with germline DNA from peripheral blood, is being biobanked. The estimated sample size is 86 cases and 172 controls, and the overall registry is anticipated to run for at least 5 years. Descriptive statistics will be used to describe the demographic and phenotypic characteristics of IBD, and incidence and prevalence will be estimated for Harare. Risk factors for IBD will be analysed using conditional logistic regression. For microbial analysis, alpha diversity and beta diversity will be compared between cases and controls, and between IBD phenotypes. Mann-Whitney U tests for alpha diversity and Adonis (Permutational Multivariate Analysis of Variance) for beta diversity will be computed. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the Parirenyatwa Hospital's and University of Zimbabwe's research ethics committee and the Medical Research Council of Zimbabwe. Findings will be discussed with patients, and the Zimbabwean Ministry of Health. Results will be presented at scientific meetings, published in peer reviewed journals, and on social media. TRIAL REGISTRATION NUMBER: NCT04178408.