Effect of Vitamin D and Calcium Supplementation on the Kidney Function and Quality of Life of Patients with Chronic Kidney Disease (CKD): A Systematic Review and Meta-Analysis

ObjectiveThis systematic review evaluates whether vitamin D and calcium supplementation benefits Chronic kidney disease (CKD) patients Quality of Life (QoL) and Renal function. BackgroundCKD disrupts calcium-phosphate homeostasis, leading to secondary hyperparathyroidism and bone mineral disorders. Efficacy of vitamin D and calcium supplementation in managing CKD remains controversial. MethodsPubMed, Google Scholar, Science Direct and EBSCO were searched from October 2024 to February 2025. Fifteen out of 82 identified studies were included. Data quality was assessed using Critical Appraisal Skills Programme (CASP) while bias risk was visualized using Robvis. Estimated Glomerular Filtration Rate (eGFR) and Parathyroid Hormone (PTH) outcomes were analysed using meta-analysis, whereas Bone Mineral Density (BMD) and Quality of Life (QoL) were assessed through narrative synthesis. ResultsVitamin D supplementation had no significant effect on eGFR (MD=0.84mL/min/1.73m{superscript 2},95%CI: -0.47 to 2.15, p=0.207) or PTH levels (MD = -6.76,95%CI: -34.92 to 1.95, p=0.005). No significant differences were found between active and inactive vitamin D supplementation on kidney function, while the results for BMD and QoL were inconclusive. ConclusionVitamin D supplementation had no significant effects on kidney function or QoL. Limited data precluded conclusions about calcium supplementation. Future studies are needed to clarify the roles of these treatments on CKD. Trial Registration NumberPROSPERO registration CRD42024607320. O_LIWhat is already known on this topic - Chronic Kidney Disease is a known progressive condition that affects over 10% of the global population. One of the most significant complications of CKD is the disruption if the calcium and phosphate balance, leading to conditions like secondary hyperparathyroidism. These complications can cause a significant impairment on the QoL of CKD patients. Vitamin D supplementation has become a standardised therapy for management of these complications, however there is a lack of clinical evidence in the effectiveness of these treatments. C_LIO_LIWhat this study adds - Despite the fact that vitamin D supplements are widely recommended to CKD patients, the evidence from the studies included in this systematic review showed no statistically significant effects. Furthermore, this review highlights the limited research on the effects of calcium supplementation, specifically in combination with vitamin D supplementation. C_LIO_LIHow this study might affect research, practice or policy - This systematic review highlights the need for more rigorous clinical trials to assess the safety and efficacy of vitamin D and vitamin C supplementation in CKD patients. This research should also explore the long term effects and determine the impact of these treatments at different stages of CKD to determine whether these treatments are more effective at certain stages of the disease. C_LI