Vitamin D supplementation significantly improves anaemia in CKD patients undergoing hemodialysis

The analysis revealed a significant increase in haemoglobin levels with vitamin D supplementation, particularly after 12 and 18 months of the supplementation.

Chronic kidney disease is defined as a glomerular filtration rate (GFR) of below 60 mL/min per 1·73 m². In the general population, its global prevalence is estimated to be >10%.

Mineral bone disease and anaemia are common complications of CKD. RBC production by bone marrow and an increase in haemoglobin levels are driven by erythropoietin which is produced by the kidney. The kidney is responsible for the conversion of vitamin D to calcitriol, and it regulates intestinal absorption of phosphate and calcium. Vitamin D is also involved in erythropoiesis induction by raising erythropoietin levels and stimulating erythrocyte precursor cell receptors.

Saad Ahmad, Orthopedic Surgery, Taj Medical Center, Nowshera, PAK, and colleagues aimed to evaluate the impact of vitamin D supplementation on haemoglobin levels (Hb) in patients with chronic kidney disease undergoing hemodialysis by conducting a systematic review and meta-analysis.

For this purpose, the researchers conducted a systematic search in electronic databases from inception to April 21, 2023. Inclusion criteria were applied to select relevant studies. Heterogeneity was addressed using a random-effects model, and the mean difference (MD) was reported.

The analysis included ten studies comprising one retrospective observational study, two randomized clinical trials, and seven clinical trials. Subgroup analysis was conducted based on the duration of follow-up: 12 weeks, three months, six months, 12 months, 15 months, and 18 months.

The researchers reported the following findings:

• A significant increase in haemoglobin levels was observed after 12 months (MD = -0.98) and 18 months (MD = -1.80).
• No statistically significant relationship was observed between vitamin D supplementation and haemoglobin levels at 12 weeks, three months, six months, and 15 months.
• The pooled analysis demonstrated a significant increase in haemoglobin levels with vitamin D supplementation (MD = -0.61).

"Our meta-analysis led to notable findings regarding the effects of vitamin D supplementation on haemoglobin levels in CKD patients," the researchers wrote. "We observed statistically significant improvements, particularly after 12 months.'

However, the researchers recommend conducting larger-scale trials to gain deeper insights into this subject matter and enhance the understanding.

The limitations of the study include the involvement of fewer patients in the analysis, the pooling together of different vitamin D supplementation, and the stratification based on dosage was not conducted. However, these factors were pivotal in conducting this study, the researchers noted.

Reference:

Ahmad S, Ullah H, Khan M I, et al. (June 23, 2023) Effect of Vitamin D Supplementation on the Hemoglobin Level in Chronic Kidney Disease Patients on Hemodialysis: A Systematic Review and Meta-Analysis. Cureus 15(6): e40843. doi:10.7759/cureus.40843