Vitamin D and micro-inflammatory state in hemodialysis patients: a mini review and meta-analysis

There is growing evidence that vitamin D (VitD) plays a role in the pathophysiological mechanism of every patient undergoing hemodialysis, and this role is significantly altered in a microinflammatory state. However, it is unclear whether supplementation dosage or route of administration should be altered due to this state. Thus, the objective of our mini review and meta-analysis was to re-consider supplementation of VitD in HD patients exhibiting micro-inflammatory state. Pubmed, Web of Science and Google Scholar were searched up to January 19, 2016. We included studies that evaluated supplementation in HD patients with micro-inflammatory state. One reviewer extracted data and one reviewer verified the data accuracy. We qualitatively summarized the main results and meta-analyzed data on comparable outcomes across studies. The main outcome measures were serum levels of VitD. Ten eligible studies were published between 2002 and 2016, involving a total 1,239 patients. Average vintage of hemodialysis was 35.36 (±31.08) months. We identified a high degree of clinical diversity (interventions and outcomes) and methodological heterogeneity (sample size and risk of bias) in included trials. The studies we reviewed provide some weak evidence to support VitD supplementation in patients on hemodialysis exhibiting micro-inflammatory state. We recommend that future trials focus on our main outcome measures (that is variable comparable across studies).