Vitamin D as a predictor of clinical response among patients with cardiac resynchronization therapy (CRT).

Introduction: Cardiovascular and noncardiovascular comorbidities have been recognized as predictors of clinical response in patients receiving cardiac resynchronization therapy (CRT). However, data on vitamin D as a predictor of CRT response are conflicting. Method: We identified studies from MEDLINE and Embase databases, searching from inception to May 2024, to investigate the association between 25-OH vitamin D levels before CRT implantation and outcomes. Studies had to report 25-OH vitamin D levels or the proportion of patients with vitamin D insufficiency and categorize outcomes as CRT responders or nonresponders. We extracted mean 25-OH vitamin D and standard deviations for both groups from each study and calculated the pooled mean difference (MD). We also retrieved risk ratios, and 95% confidence intervals (CIs) for the association between vitamin D insufficiency and lack of CRT response, combining them using the generic inverse variance method. Results: Our meta-analysis included four studies. CRT responders had higher levels of 25-OH vitamin D than nonresponders, with a pooled MD of 8.04 ng/mL (95% CI: 3.16-12.93; Conclusions: CRT responders had higher 25-OH vitamin D levels compared to nonresponders. Vitamin D insufficiency was associated with a higher risk of nonresponse to CRT. These findings highlight the importance of monitoring and managing vitamin D levels in these patients.