Best abstract award 2011

Vitamin D: a prognostic marker in heart failure patients?

Liu, L.C.Y. (1), A.A. Voors MD/PHD (1), D.J. Van Veldhuisen MD/PHD (1), E. Van der Veer PHD (2), A.M. Belonje MD (1), M.K. Szymanski MD (1), H.H.W. Silljé PHD (1), W.H. Van Gilst PHD( 1), T. Jaarsma MD/PHD (1), R.A. De Boer MD/PHD(1)

(1) University Medical Center Groningen, Department of Cardiology, Groningen, Netherlands
(2) University Medical Center Groningen, Department of Laboratory Medicine, Groningen, Netherlands

Introduct ion
Vitamin D status has been implicated in the pathophysiology of heart failure (HF). An activated renin-angiotensin-system (RAS) and a pro-inflammatory status play an important role in the development en progression of HF. Low vitamin D levels have been shown to be inversely related to plasma renin activity (PRA), resulting in RAS activation. Further, vitamin D supplementation suppresses the release of inflammatory markers. We hypothesize that a low vitamin D status is associated with a poor prognosis in HF, and that RAS activation or inflammation explain this potential association.

Material & methods
We measured 25-hydroxy-vitamin D (25(OH)D), PRA, interleukin-6 (IL-6), C-reactive protein(CRP), and the incidence of death or rehospitalization in 548 patients from the COACH study (Coordinating study evaluating Outcomes of Advising and Counselling in Heart Failure). Data were analysed by linear regression, Kaplan-Meier analysis and Cox regression. Potential differences in survival rates were tested with the log rank test (SPSS 17.0). A P-value of <0.05 was considered statistically significant.

Results
Median age was 74 (64-80) years, left ventricular ejection fraction 30% (23-42) and mean follow-up was 18 months. Low 25(OH)D levels were associated with female gender (P<0.001), higher age (P=0.002), and higher N-terminal pro-brain natriuretic peptide (NT-proBNP) levels (P<0.001). Multivariable linear regression analysis showed that PRA (P=0.048), and CRP levels (P=0.006) were independent predictors of 25(OH)D levels. During follow-up, 155 patientsdied and 142 patients were rehospitalized. Kaplan-Meier analysis showed that lower 25(OH)D concentration was associated with an increased risk for the combined endpoint (all-cause mortality and HF rehospitalization; log rank test P=0.045) and increased risk for all-cause mortality (log rank test P=0.014). After adjustment in a multivariable Cox regression analysis, low 25(OH)D concentration remained independently associated with an increased risk for thecombined endpoint (HR 1.09 per 10 nmol/L decrease; 95% CI 1.00-1.16; P=0.040) and all-cause mortality (HR 1.10 per 10 nmol/L decrease; 95% CI 1.00-1.22; P=0.049).

Conclusion
A low 25(OH)D concentration is associated with a poor prognosis in HF patients. Activation of the RAS and inflammation may confer the adverse effects of low vitamin D level