BackgroundAccurate contemporary data on the burden of Chronic Kidney Disease (CKD) on the African continent are lacking. We determined the prevalence of CKD in adult populations living in Africa, and variations by stage, gender, estimated Glomerular Filtration Rate (eGFR) equation, and residence.MethodsFor this systematic review, we searched multiple electronic databases for original studies on CKD prevalence reported from January 1, 2000 to December 31, 2016. Two reviewers independently undertook quality assessment and data extraction. We stabilized the variance of study-specific estimates with the Freeman-Turkey single arcsine transformation and pooled the data using a random effects meta-analysis models.ResultsA total of 98 studies involving 98,432 individuals were included in the final meta-analysis. The overall prevalence was 15.8% (95% CI 12.1–19.9) for CKD stages 1–5 and 4.6% (3.3–6.1) for CKD stages 3–5 in the general population. Equivalent figures were greater at 32.3% (23.4–41.8) and 13.3% (10.7–16.0) in high-risk populations (people with hypertension, diabetes, HIV). CKD prevalence was higher in studies based on the Cockcroft-Gault formula than MDRD or CKD-EPI equations; and in studies from sub-Saharan Africa compared with those from North Africa (17.7, 95% CI 13.7–22.1 vs 6.1, 95% CI 3.6–9.3, p < 0.001). There was substantial heterogeneity across studies (all I2 > 90%) and no evidence of publication bias in main analyses.ConclusionCKD is highly prevalent across Africa, inviting efforts into prevention, early detection and control of CKD in adults living on the African continent which is particularly important in a resource limited environment.Trial RegistrationProspero Registration ID: CRD42017054445.Electronic supplementary materialThe online version of this article (10.1186/s12882-018-0930-5) contains supplementary material, which is available to authorized users.

Few studies have evaluated whether histopathologic lesions on kidney biopsy provide prognostic information beyond clinical and laboratory data. We enrolled 676 individuals undergoing native kidney biopsy at three tertiary care hospitals into a prospective, observational cohort study. Biopsy specimens were adjudicated for semiquantitative scores in 13 categories of histopathology by two experienced renal pathologists. Proportional hazards models tested the association between histopathologic lesions and risk of kidney disease progression (≥40% eGFR decline or RRT). Mean baseline eGFR was 57.5±36.0 ml/min per 1.73 m During follow-up (median, 34.3 months), 199 individuals suffered kidney disease progression. After adjustment for demographics, clinicopathologic diagnosis, and laboratory values, the following lesions (hazard ratio; 95% confidence interval) were independently associated with progression: inflammation in nonfibrosed interstitium (0.52; 0.32 to 0.83), moderate and severe versus minimal interstitial fibrosis/tubular atrophy (2.14; 1.24 to 3.69 and 3.42; 1.99 to 5.87, respectively), moderate and severe versus minimal global glomerulosclerosis (2.17; 1.36 to 3.45 and 3.31; 2.04 to 5.38, respectively), moderate and severe versus minimal arterial sclerosis (1.78; 1.15 to 2.74 and 1.64; 1.04 to 2.60, respectively), and moderate and severe versus minimal arteriolar sclerosis (1.63; 1.08 to 2.46 and 2.33; 1.42 to 3.83, respectively). An 11-point chronicity score derived from semiquantitative assessments of chronic lesions independently associated with higher risk of kidney disease progression (hazard ratio per one-point increase, 1.19; 95% confidence interval, 1.12 to 1.27). Across a diverse group of kidney diseases, histopathologic lesions on kidney biopsy provide prognostic information, even after adjustment for proteinuria and eGFR.

Uric acid concentration is an independent risk factor for kidney failure in earlier stages of CKD and has a J-shaped relationship with all-cause mortality in CKD. Adequately powered randomized placebo-controlled trials in CKD are needed to test whether urate lowering may prove to be an effective approach to prevent complications and progression of CKD.