Israel Medical Association Journal

Background: Vitamin B6 is an essential cofactor in amino acid metabolism. Its deficiency is linked to neuropathy, anemia, and cardiovascular risk. Deficiency is common among hemodialysis patients due to dialytic losses and restrictive diets; however, data related to high-flux (HF) dialysis membranes and Mediterranean dietary patterns are scarce.

Objectives: To assess the prevalence and determinants of deficiency in unsupplemented Israeli hemodialysis patients.

Methods: This retrospective chart review, utilizing a cross-sectional design, was conducted in August 2024. We included 27 chronic hemodialysis patients not receiving vitamin B6 supplementation, representing the available unsupplemented cohort from a unit of approximately 150 patients. Vitamin B6 status was assessed by measuring plasma pyridoxal-5'-phosphate (PLP); deficiency < 20 ng/ml. Clinical and nutritional parameters were evaluated to identify deficiency.

Results: Vitamin B6 deficiency was noted in 63% of patients (median PLP 18 ng/ml, interquartile range 13–23). The cohort was 67% male, median age 74 years. All patients were treated with HF dialyzers. No significant correlations were found between PLP levels and nutritional indices or laboratory markers. A non-significant trend was observed between older age and lower PLP levels (r = -0.35, P = 0.098).

Conclusions: Vitamin B6 deficiency was common among Israeli hemodialysis patients treated with HF dialyzers, despite a presumed Mediterranean diet. It was not associated with nutritional status, suggesting dialysis-related losses, potentially augmented by high-flux membranes, may outweigh intake. Given the high prevalence of deficiency and low cost, routine low-dose vitamin B6 supplementation may be warranted, particularly in older patients.

Background: Cardiac resynchronization therapy (CRT) is a non-pharmacological option for patients with heart failure and interventricular dyssynchrony. Elevated red cell distribution width (RDW) reflects higher size and heterogeneity of erythrocytes and is associated with poor outcome in patients with chronic heart failure. 

Objectives: To examine the association between RDW levels and outcomes after CRT implantation.

Methods: We conducted a cohort analysis of 156 patients (126 men, median age 69.0 years) who underwent CRT implantation in our institution during 2004–2008. RDW was measured at three time points before and after implantation. Primary outcome was defined as all-cause mortality, and secondary outcome as hospital re-admissions. We investigated the association between RDW levels and primary outcome during a median follow-up of 61 months.

Results: Ninety-five patients (60.9%) died during follow-up. Higher baseline RDW levels were associated with all-cause mortality (unadjusted HR 1.35, 95%CI 1.20–1.52, P < 0.001). On multivariate analysis adjusted for clinical, electrocardiographic and laboratory variables, baseline RDW levels were associated with mortality (HR 1.33, 95%CI 1.16–1.53). RDW levels 6 months and 12 months post-implantation were also associated with mortality (HR 1.22, 95%CI 1.08–1.38, P = 0.001; and HR 1.15, 95%CI 1.01–1.32, P = 0.02, respectively). Patients who were re-admitted to hospital during follow-up (n=78) had higher baseline RDW levels as compared to those who were not (14.9%, IQR 14.0, 16.0% vs. 14.3%, IQR 13.7, 15.0%, respectively, P = 0.03). 

Conclusion: An elevated RDW level before and after CRT implantation is independently associated with all-cause mortality.