Background: Non-ischemic dilated cardiomyopathy (DCM) is a progressive heart disease often affecting young individuals leading to heart failure (HF) development, heart transplantation (HT) and adverse outcome. We aimed to evaluate the prevalence of hypovitaminosis D among Italian patients with DCM and its prognostic value during follow-up.
Methods: Plasma vitamin D levels were measured in 204 patients with DCM enlisted from The Trieste Registry of Cardiomyopathies. The endpoints during follow-up were defined as the incidence of major ventricular arrhythmias (MVAs), HT, hospitalization for HF and all-cause mortality.
Results: The median concentration of vitamin D in our cohort was 20.7 (15.53-29.3) ng/ml) and the majority of enrolled individuals were vitamin D deficient (54.4%). Vitamin D levels positively correlated with left ventricular ejection fraction (LVEF) (R=0.216, p=0.002) and patients with LVEF > 35 have significantly higher plasma vitamin D concentration compared to patients with LVEF <= 35 (respectively, 22.7 (17.35 – 30.5) ng/ml vs 19.2 (13.0 – 26.35) ng/ml, p=0.009).
During a median follow-up of 58.47 (38.05 – 74.97) months, 7.8% of patients died, 3.9% had HT, 12.3% of individuals were hospitalized for HF, and 12.7% suffered from MVAs.
Deceased individuals, patients requiring HT and hospitalized for HF during follow-up were observed to have significantly lower plasma vitamin D values compared to living and event-free individuals at the end of follow-up (respectively, 18.65 (9.49 – 20.7) ng/ml vs 21.3 (15.75 – 29.58) ng/ml, p=0.046, 14.35 (7.03 – 17.85 ng/ml vs 20.9 (15.9 – 29.48) ng/ml, p=0.021, 15.5 (9.56 – 21.35) ng/ml vs 21.7 (16.2 – 29.5) ng/ml, p= 0.012). In addition, patients suffering from MVAs had lower vitamin D values compared to individuals without events, although not significant (18.8 (14.48 – 24.48) ng/ml 21.56 (15.6 – 29.53) ng/ml, p=0.219). Unfortunately, Kaplan-Meier analysis and multivariate Cox regression analysis did not show an association and prognostic feature of vitamin D levels with events as expected probably due to the limited number of samples.
Conclusions: Hypovitaminosis D is common in patients with DCM. Given that lower levels of vitamin D are noted among patients with MVA, HT, HF hospitalization and poor outcome, future studies with a larger cohort are needed to confirm its predictive value. Vitamin D supplementation should be highly recommended as part of preventive therapies in patients with DCM.