Prevalence and determinants of poor outcome in patients with chronic kidney disease in low-income countries in sub-Saharan Africa: a systematic review

¹Department of Public Health, School of Medicine and Health Sciences, University of Lusaka, Lusaka, Zambia, ²Department of Public Health, Mulungushi University, Livingstone, Zambia

^&Corresponding author
Chitalu Chanda, Department of Public Health, Mulungushi University, Livingstone, Zambia

Introduction    

Chronic Kidney Disease (CKD) is associated with significant healthcare costs, morbidity, and mortality [1,2]. Globally, the prevalence of chronic kidney disease is estimated at around 10% [1,3]. On the African continent, the prevalence of chronic kidney disease was approximately between 10 and 15% among adults [4,5]. Chronic kidney disease is often associated with other conditions such as Human Immunodeficiency Virus (HIV), use of non-steroidal anti-inflammatory drugs, diabetes mellitus, hypertension, viral hepatitis, and cardiovascular disease [1,6,7]. There has been an increase in the prevalence of non-communicable conditions such as hypertension, diabetes mellitus and obesity in Africa [8]. Even among HIV positive patients, whose prevalence is highest in Africa, the incidence of non-communicable diseases has greatly increased [9,10].

Epidemiology transition of CKD in Africa has been documented in remote and rural areas [11]. This could be influenced by the ability to diagnose the condition through increased testing of markers of chronic kidney disease in Africa. Furthermore, the prevalence could be influenced by increased risk factors such as obesity, hypertension, and diabetes mellitus in Africa [12]. The morbidity usually associated with chronic kidney disease is poor quality of life and increased health care costs. The outcome of mortality among chronic kidney disease patients is influenced by age, stage of kidney disease, anaemia, hemodialysis, comorbidity conditions, and renal replacement therapy [1,2,13,14]. Therefore, the study sought to explore the prevalence of Chronic Kidney Disease as well as factors associated with outcomes in sub-Saharan Africa.

The research question was: What is the prevalence and factors associated with chronic kidney disease in sub-Saharan Africa? The objectives of this study were to investigate the prevalence of chronic kidney disease among adults in sub-Saharan Africa, to examine the factors associated with the prevalence of chronic kidney disease in sub-Saharan Africa and to explore the outcomes associated with mortality among patients with chronic kidney disease in sub-Saharan Africa

Methods     

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines to guide the review of articles, and the quality of the studies was measured and assessed using the Ottawa Newcastle scoring tool adapted for cross-sectional studies.

Data sources and search strategy: we conducted a comprehensive search across multiple databases, including Google Scholar and PubMed, using key search words such as "Mortality" OR "Rate" AND "Outcome" AND "Chronic Kidney diseases" AND "factors associated" AND "Low-Income countries (LMIC)" AND "sub-Saharan Africa" as shown in Table 1. The search encompassed studies conducted from 2018 to 2023. The search was conducted and verified before outcomes were input into Rayyan, an online platform for data screening and eligibility analysis.

Selection criteria: the selection criteria included all studies that all published articles that reported (i) have participants who were 15 years and above (ii) diagnosis of chronic kidney disease was established as defined by creatinine clearance of less than 65 mmol/hr (iii) all observations, cross-sectional, randomized control studies and case-controls were included in the analysis that reported prevalence and/or associated factors for the chronic kidney disease (iv) Studies done in sub-Sahara Africa (iv) within 5 years of publication. The following exclusion criteria were used during the screening and review of the search (i) All studies in languages that were English (ii) abstracts and conference posters (iii) publications that were beyond 10 years (iii) studies that were not done in sub-Saharan Africa (iv) review articles and case series will be excluded. All titles and/or abstracts were examined by at least two reviewers, with a minimum of at least two reviewers agreeing to include the article. EK verified the decisions. Those not meeting the criteria after reviewing the abstract and title were excluded. If there was a conflict of decision regarding the articles, a third reviewer was asked to review and decide. After the first evaluation and screening, all the remaining articles were fully read, and the studies meeting the inclusion criterion were included in the systematic review. Disparities were resolved through discussion.

Data extraction: the reviewers participated in the data extraction from the included articles. The following information was extracted: - Journal title/name, name of author, Year of publication, study design, number of participants, the prevalence of chronic kidney disease, stage of kidney disease, Odds Ratio or Relative Risk or Hazard Ratio for risk factors, mortality (outcome). The data was extracted using Rayyan and Excel.

Quality assessment: the quality of the studies was assessed using the Newcastle-Ottawa scoring tool, which is attached in the Supplementary appendix (Table 2) [15]. The grading system followed for the Newcastle -Ottawa score was: (0-3)- poor quality, (3-5)- Fair quality and (6-9)- good quality. All articles scored between 6 and 9 and were classified and rated as good quality.

Results     

Study selection: the search retrieved 2562 articles, of which 32 were selected for full text review. Of these eligible studies, 10 were included for data abstraction, as shown in the PRISMA diagram in Figure 1.

Characteristics of studies included: ten studies were included in the analysis. Table 3 highlights the features of the studies included. The total number of participants was 6963. All 10 studies were cross-sectional. The majority of studies were conducted in one country (six), while others were distributed across the other regions in sub-Saharan Africa. All the articles included had a good assessment with the Newcastle Ottawa assessment tool.

Study characteristics: the 10 studies were carried out in a variety of geographic locations: Ethiopia (n=6), Tanzania, Sierra Leone, Cameroon, and Ghana ( n=1 in each country). All 10 included articles represented cross-sectional studies.

Study settinga total of 6963 participants were studied in the systematic review across 10 articles. Most of these participants were recruited in a health facility (clinic or hospital), as depicted in 7 out of 10 articles (70%) and the rest were recruited in a community-based setting, as depicted in 3 out of the 10 articles (30%).

Prevalence: the primary outcome of interest was the prevalence of chronic kidney disease. The study definition of chronic kidney disease was renal creatinine clearance of less than 65 mmol/hr. The prevalence rate ranged from 9.8 to 29.9% as shown in Table 4 [1,4,16-22]. None of the 10 studies that were included explored the outcome of mortality among the patients. There was no report of associated factors to the poor outcome.

Effect of age: the ages of the participants were 18 years and above. Prevalence of CKD increased with age. 2 studies out of 10 (20%) (Kachimanga et al. 2021; Ali et al. 2023) compared the odds of CKD prevalence by age, comparing those 40-60years to those above 60years. The mean odds ratio for those 40-60 years was 0.7333 compared to the odds ratio of those above 60 years, which was 1.566. This indicated that those above 60 years had a higher likelihood of developing CKD compared to those below 60 years. Another study with 620 participants (Sertsu et al. 2022) [20-22] compared the odds of CKD prevalence between those below 60 years and those above 60 years. The odds of CKD prevalence in those above 60 years were 1.83 compared to those below 60. This study also indicated that the prevalence of CKD increases with age.

Effect of hypertension and diabetes on CKD: in this systematic review, the major comorbidities were DM and HTN, which were correlated with CKD with varying odds ratios. 6 out of 10 articles (60%) reported odds ratios for Diabetes mellitus about CKD ranging from 0.0963 to 2.13. 3 out of the 6 articles (50%) reported a reduced odds ratio of diabetes about CKD, while the other 50% of the articles reported twice as likely of the diabetics to develop CKD [1,19-23]. Poorly controlled diabetes increases the chances of developing CKD. Eight out of 10 articles (80%) reported odds ratios of hypertension about CKD ranging from 0.001188 to 9.45. Only 1 article of the 8 (12.5%) had a reduced odds of hypertension about CKD, 7 out of 8(87.5%) showed an increased likelihood of CKD in the presence of hypertension. Hypertension, therefore, increases the chances of developing CKD. Only 1 article reported COVID-19 in CKD, and there was no report on any association with CKD. There was only one article that reported the effect of HIV on CKD, with the association not being statistically not signficant.

Discussion     

This systematic review included 10 studies in which all the studies reported the prevalence of chronic kidney disease. The reported range of prevalence was higher than previously shown in some studies [6,12,19,24]. The included studies showed a reduced risk of bias as demonstrated by the Newcastle-Ottawa assessment score.

The studies included showed a heterogeneous distribution of the comorbid conditions related to chronic kidney disease. Most of the articles included didn´t include COVID-19 among the variables of interest and impact. Only one paper refers to COVID-19. As seen from previous studies, the risk of chronic kidney disease was associated with other non-communicable diseases such as diabetes mellitus and hypertension [12,20,25].

Only one study explored the association between chronic kidney disease and HIV despite the prevalence of HIV being higher in sub-Saharan Africa [20]. Among the associated risk factors, at least 6 studies showed that hypertension was associated with chronic kidney disease [18,20-23,26]. However, this association does not highlight causality between hypertension and chronic kidney disease. The increased coexistence of the comorbid conditions might have a significant impact on polypharmacy, health costs, and quality of life [2]. This can be seen as some studies reported increased use of non-steroidal anti-inflammatory drugs, which might worsen kidney function. Age and increased Body mass index were reported among some studies as being associated with CKD [18]. These could indicate that routine screening can be recommended in those of increased age for non-communicable diseases.

Three studies reported cardiovascular disease with a statistically significant association being demonstrated [18,20,22]. The mortality related to CKD and cardiovascular disease has been previously shown [24]. Only one article reported COVID-19 in CKD, and there was no report on any association with CKD. No article reported the effect of HIV on CKD. However, there is an association with severe forms of COVID-19 in those with CKD [27,28]. The COVID-19 pandemic has recently affected many regions of Africa. One of the observations was reduced health facility attendance and reduced service provision during the pandemic [29,30]. However, COVID-19 was associated with increased unfavourable outcomes in those with comorbid conditions such as diabetes mellitus and hypertension, which are increased among patients with chronic kidney disease [27].

Outcome of CKD: none of the studies looked at the secondary outcome of mortality or its associated factors. No article reported outcomes relating to anaemia, infections, heart failure, or mortality. A previous systematic review, including data from 1990 to 2017, showed that all-cause mortality was 4.6% [24].

Limitations: conducting studies on chronic kidney disease (CKD) during the COVID-19 pandemic presented several challenges. In several situations, access to SARS-CoV-2 testing differed dramatically between patient groups. Furthermore, baseline renal function data were frequently missing, making it difficult to appropriately diagnose CKD and acute kidney damage in several trials. Researchers encountered problems due to variations in virus prevalence, targeted public health programmes, and vaccination rates. These differences influenced the incidence of SARS-CoV-2 infection throughout time and place, thus affecting the generalizability of findings of its impact on patients with chronic kidney disease. The excluded trial due to language could have had some significant findings which could not be interpreted.

Conclusion     

This review has shown and supported that the prevalence of chronic kidney disease is high in sub-Saharan Africa. Other non-communicable diseases, such as hypertension, cardiovascular disease, and diabetes, are significantly associated with chronic kidney disease. The outcomes of chronic disease remain poorly described in sub-Saharan Africa.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Chitalu Chanda, Eustarckio Kazonga, Natasha Ngwenya, Mukuka Chibamba, Christabel Silavwe and Nomanthombi Johnson conceptualised the study. Chitalu Chanda, Natasha Ngwenya, Mukuka Chibamba, Christabel Silavwe and Nomanthombi Johnson did the searching and screening of articles. Chitalu Chanda, Eustarckio Kazonga, Natasha Ngwenya, Christabel Silavwe and Nomanthombi Johnson did the writing. Chitalu Chanda, Eustarckio Kazonga, and Natasha Ngwenya did the article quality assessment. Christabel Silavwe and Nomanthombi Johnson were on scoring. Chitalu Chanda was on data extraction and cleaning. Eustarckio Kazonga did the verification of articles. Natasha Ngwenya reviewed articles, cleaned data in Excel, and compiled results. Chitalu Chanda and Natasha Ngwenya edited. Eustarckio Kazonga, Natasha Ngwenya and Christabel Silavwe reviewed. All authors read and approved the final version of the manuscript.

Tables and figure     

Table 1: search characteristics

Table 2: assessment of the quality of the study using New Castle Ottawa adapted for a cross-sectional study

Table 3: study characteristics

Table 4: prevalence and associated factors of chronic kidney disease in sub-Sahara Africa

Figure 1: PRISMA flow diagram

Annex     

Annex 1: supplementary material (PDF 257 KB)

References