| Abstract: | Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are associated with significant cardiovascular (CV) and renal morbidity and mortality rates, with substantial economic burden.1,2 Therefore, early identification of CKD patients at high risk of progression is urgently needed for early and targeted treatment to improve patient care.1-3 Diabetes and hypertension are the primary risk factors for CKD and ESRD but do not fully account for CKD and ESRD risk.1-3 Marked variability in the incidence of CKD suggests that factors other than diabetes and hypertension contribute to its aetiology.4Family studies have suggested a genetic component to the aetiology of CKD and ESRD.5 In African Americans, high-risk common variants in the Apol1/MYH9 locus may explain up to 70% of the differences in ESRD rates between European and African Americans.5 While this finding has great implications for ESRD, the identification of additional risk factors for CKD, including genetic loci in association with estimated glomerular filtration rate (eGFR), may help to advance our understanding of the underpinnings of CKD in African Americans.5 In this era of identifying genetic risk factors for kidney disease, it may be appropriate to revisit one of the most common genetic disorders: sickle cell haemoglobinopathies.5In this regard, sickle cell trait (SCT), present in approximately 7–9% of African Americans, has been reported to be a potential candidate gene.6 However, conflicting reports exist as to whether SCT is a risk factor for the progression of nephropathy.6,7 Haemoglobin S (HbS) was selected for in Africa because of the protection it affords from malarial infection, a scenario similar to the protection from trypanosomal infection provided by heterozygosity for APOL1 nephropathy risk variants.6Whereas APOL1 contributes to risk for nephropathy in an autosomal recessive inheritance pattern, HbS reportedly had a dominant effect on risk, with SCT being associated with ESRD.6 In line with this finding, a few small studies on African Americans reported HbS as an independent risk factor for CKD and ESRD.8 However, other studies using a large sample of African Americans stated that SCT was not independently associated with susceptibility to ESRD in African Americans,6 highlighting the need for further studies in other populations such as those of sub-Saharan Africa where SCT is prevalent.Although SCT is very prevalent in black Africans,9 few studies have been conducted to assess the association between SCT and CKD.10 In Democratic Republic of Congo (DRC), the prevalence of CKD and SCT has been reported to be 12% and 17–24%, respectively.11-13 No study has evaluated the frequency of SCT among CKD patients to assess its association with reduced kidney function. Therefore, the aim of this clinic-based, cross-sectional study was to assess the potential association between SCT and CKD among adult Congolese patients. |
