Effects of vitamin D supplements on bone metabolism in kidney transplant recipients: a systematic review and meta-analysis.
- 2025-09-24
- Systematic reviews 14(1)
- Peishan Cai
- Zhou Shu
- Taotao Zhou
- Jie Li
- Wei Chen
- Xianpeng Zeng
- Fang Zeng
- PubMed: 40993781
- DOI: 10.1186/s13643-025-02828-w
Study Design
- Type
- Meta-Analysis
- Sample size
- n = 985
- Population
- 985 KTRs
- Methods
- Meta-analysis of 14 RCTs; searched PubMed, EMBASE, Web of Science, and the Cochrane Library for RCTs up to September 30, 2023; pooled analysis using RR or SMD.
- Duration
- 3 to 12 months
Background
Vitamin D has been reported to decrease parathyroid hormone (PTH), reduce bone loss, and promote calcium absorption. However, its effects on bone metabolism in kidney transplant recipients (KTRs) remain controversial. This review aimed to analyze the effects of vitamin D supplements on bone metabolism in KTRs.Methods
We searched PubMed, EMBASE, Web of Science, and the Cochrane Library from inception through September 30, 2023, for randomized controlled trials (RCTs) on the effect of vitamin D on bone metabolism after kidney transplantation. We also searched the reference lists of systematic reviews and included studies. The outcomes were expressed using relative risk (RR) or standardized mean difference (SMD) with the corresponding 95% confidence interval (CI).Results
Fourteen studies involving a total of 985 KTRs were included in this analysis. The treatments consisted vitamin D supplementation at various doses and types. The duration of follow-up ranged from 3 to 12 months. More than half of the 14 studies (n = 8) had an overall high risk of bias, as they had at least one high-risk domain. Compared to placebo or no treatment, vitamin D supplementation significantly improved bone mineral density (BMD) at the femoral neck (SMD 0.54; 95% CI 0.10 to 0.98; P = 0.02), reduced serum PTH level (SMD -0.49; 95% CI -0.76 to -0.22; P = 0.0003), decreased bone alkaline phosphatase (BAP) level (SMD -0.31; 95% CI -0.52 to -0.09; P = 0.006), increased serum calcium level (SMD 0.35; 95% CI 0.12 to 0.58; P = 0.003) and increased the risk of hypercalcemia (RR 1.92; 95% CI 1.23 to 3.01; P = 0.004). After treatment, there were no significant differences in the changes in lumbar spine BMD, 25-hydroxyvitamin D (25[OH]D) level, serum phosphate level, serum alkaline phosphatase (ALP) level, calciuria level, proteinuria level and estimated glomerular filtration rate (eGFR). No significant differences were observed in the incidence of fracture and acute graft rejection.Conclusions
Vitamin D supplementation does not improve overall BMD or prevent fracture in KTRs. Vitamin D supplementation may effectively reduce serum PTH and BAP level. However, it may also increase the risk of hypercalcemia, necessitating the monitoring of serum calcium level.Research Insights
After treatment, there were no significant differences in the changes in lumbar spine BMD
- Effect
- Neutral
- Effect size
- Small
- Dose
- various doses and types
After treatment, there were no significant differences in the changes in ... estimated glomerular filtration rate (eGFR)
- Effect
- Neutral
- Effect size
- Small
- Dose
- various doses and types
After treatment, there were no significant differences in the changes in ... 25-hydroxyvitamin D (25[OH]D) level
- Effect
- Neutral
- Effect size
- Small
- Dose
- various doses and types
increased the risk of hypercalcemia (RR 1.92; 95% CI 1.23 to 3.01; P = 0.004)
- Effect
- Harmful
- Effect size
- Moderate
- Dose
- various doses and types
increased serum calcium level (SMD 0.35; 95% CI 0.12 to 0.58; P = 0.003)
- Effect
- Harmful
- Effect size
- Small
- Dose
- various doses and types
After treatment, there were no significant differences in the changes in ... serum alkaline phosphatase (ALP) level
- Effect
- Neutral
- Effect size
- Small
- Dose
- various doses and types
decreased bone alkaline phosphatase (BAP) level (SMD -0.31; 95% CI -0.52 to -0.09; P = 0.006)
- Effect
- Beneficial
- Effect size
- Moderate
- Dose
- various doses and types
After treatment, there were no significant differences in the changes in ... calciuria level
- Effect
- Neutral
- Effect size
- Small
- Dose
- various doses and types
No significant differences were observed in the incidence of fracture
- Effect
- Neutral
- Effect size
- Small
- Dose
- various doses and types
No significant differences were observed in the incidence of ... acute graft rejection
- Effect
- Neutral
- Effect size
- Small
- Dose
- various doses and types
reduced serum PTH level (SMD -0.49; 95% CI -0.76 to -0.22; P = 0.0003)
- Effect
- Beneficial
- Effect size
- Moderate
- Dose
- various doses and types
After treatment, there were no significant differences in the changes in ... proteinuria level
- Effect
- Neutral
- Effect size
- Small
- Dose
- various doses and types
After treatment, there were no significant differences in the changes in ... serum phosphate level
- Effect
- Neutral
- Effect size
- Small
- Dose
- various doses and types