Spectrum of Kidney Involvement in Sickle Cell Disease: A Systematic Review and Meta‐Analysis

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Background Sickle cell disease (SCD) is associated with progressive renal complications collectively termed sickle cell nephropathy, which significantly contribute to morbidity and mortality. However, the burden and distribution of renal manifestations across disease stages remain inconsistently reported. Objective This study aimed to systematically review and meta‐analyze the prevalence of renal involvement in individuals with SCD, including albuminuria (reported as microalbuminuria and macroalbuminuria in some studies), proteinuria, and chronic kidney disease (CKD) and to explore genotype‐ and age‐group‐specific differences. Methods A systematic review and meta‐analysis were conducted in accordance with PRISMA guidelines. PubMed, Scopus, and Google Scholar were searched from 2015 to 2026. Observational studies reporting prevalence data on renal outcomes in SCD were included. Pooled prevalence estimates were calculated using a random‐effects model with Freeman–Tukey transformation. Heterogeneity was assessed using the I 2 statistic, and subgroup analyses were performed based on genotype and age group. Results A total of thirty‐eight (38) studies were included. The pooled prevalence of albuminuria was 34% (95% CI: 27%–41%; I 2 = 93.2%). Among hemoglobin SS (HbSS) patients, albuminuria prevalence was higher at 39% (95% CI: 29%–49%; I 2 = 93.9%) and 22% (95% CI: 1%–56%; I 2 = 68.7%) among hemoglobin SC (HbSC) patients. The pooled prevalence of CKD was 43% (95% CI: 26%–61%; I 2 = 99.2%), increasing to 65% (95% CI: 35%–89%; I 2 = 96.8%) in HbSS individuals. Microalbuminuria was the most frequently reported manifestation (29%), followed by proteinuria (18%) and macroalbuminuria (11%). Age‐stratified analysis showed lower albuminuria prevalence in children (23%) compared to adults (48%), suggesting an increasing burden of renal abnormalities with age. Conclusion Renal complications are highly prevalent in SCD, with albuminuria representing an early marker of kidney injury and CKD reflecting advanced disease. The higher burden observed in HbSS patients and adults underscores the progressive nature of sickle cell nephropathy. Early detection and routine monitoring are essential to mitigate progression and improve long‐term outcomes.