Prevalence and complications of diabetes mellitus in Northern Africa, a systematic review

Methodological quality of the review: Low confidence

Author: Bos M, Agyemang C.

Region: Morocco, Algeria, Tunisia, Libya, Egypt, Sudan, South Sudan and Western Sahara

Sector: Diabetes mellitus, northern Africa

Sub-sector: complications, prevalence

Equity focus: None specified

Review Type: Effectiveness review

Quantitative synthesis method: Narrative analysis

Qualitative synthesis methods: Not applicable

Background

Type 2 diabetes is increasingly becoming a major chronic disease health burden in Africa, with the highest increase being seen in urban areas. Authors note that changing patterns of diet, physical activity, and aging populations are thought to be the major drivers of increasing prevalence in Africa. The diabetes situation in Northern Africa has not yet been systematically assessed.

Research objectives

To ‘provide an up-to-date overview on diabetes prevalence and related microvascular complications including retinopathy, nephropathy, neuropathy and micro albuminuria in North Africa’.

Main findings

Authors included 12 community-based studies which assessed the prevalence of type 2 diabetes in North Africa and included nine studies which reported on the prevalence of complications of diabetes in northern Africa.

Diabetes prevalence ranged from 2.6% in rural Sudan to 20.0% in urban Egypt. Diabetes prevalence was significantly higher in urban areas than in rural areas. Undiagnosed diabetes is common in northern Africa with a prevalence ranging from 18% to 75%. The prevalence of chronic diabetes complications ranged from 8.1% to 41.5% for retinopathy, 21% to 22% for albuminuria, 6.7% to 46.3% for nephropathy and 21.9% to 60% for neuropathy.

Authors concluded that diabetes was an important and common problem in North Africa and chronic complications are common. Variations in the prevalence of diabetes vary between countries. Urgent measures were needed to prevent diabetes and its complications in northern Africa.

Methodology

The authors included community-based studies that assessed the prevalence of diabetes and related microvascular complications, with a sample size of more than 50 participants aged 18 or over. It was not clear which other types of study design were included in the review. Authors searched PUBMED from January 1990 to July 2012. No language restrictions were used. References of included studies were also checked as part of the search strategy. Authors did not report methods used to select studies and extract data of included studies.

Authors were unable to conduct a meta-analysis since included studies used different methods to diagnose diabetes.

Applicability/external validity

The authors noted that in order to make an accurate estimate of current prevalence rates between countries, it would be ideal to compare studies in the same period of time. Due to a lack of data, this review relied upon studies conducted in differing time periods which limits the applicability of the results.

Geographic focus

The review focussed on low- to middle-income countries including Morocco, Algeria, Tunisia, Libya, Egypt, Sudan, South Sudan and Western Sahara. The results offered insight into an upward trend of the prevalence of diabetes in low- to middle-income countries.

Quality assessment

A low confidence was attributed in the conclusions about the effects of this study. The systematic review was based on the searching one database only (PUBMED) from 1990 to July 2012, with no language restrictions. Although reference lists were also searched for further relevant studies, this review may have been prone to publication bias as the authors did not search further databases including grey literature sources. Additionally, authors did not report the methods used to select studies and extract data of included studies. The review did not offer a summary of the characteristics of all of the included studies, including details of the different study designs.  Authors noted that the included studies were conducted in different years (from 1990 to 2012) and acknowledge that this limited the review’s accuracy.