UC Irvine

Objective

Markers of better nutritional status including both higher levels of serum albumin (as a measure of visceral proteins) and creatinine (as a measure of the muscle mass) are associated with lower mortality in conventional (thrice weekly) hemodialysis patients. However, data for these associations in twice-weekly hemodialysis patients, in whom less frequent hemodialysis may confound nutritional predictors, are lacking.

Design and subjects

We identified 1,113 twice-weekly and matched 4,448 thrice-weekly hemodialysis patients from a large national dialysis cohort of incident hemodialysis patients over 5 years (2007-2011). Mortality risk, adjusted for potential confounders, was examined across two-by-two combinations of serum creatinine (<6 vs. ≥6 mg/dL) and albumin (<3.5 g/dL vs. ≥3.5 g/dL) for each treatment frequency yielding a total of 8 groups.

Results

Patients were aged 70 ± 14 years and included 48% women and 55% diabetics. Using the thrice-weekly hemodialysis patients with creatinine ≥ 6 mg/dL and albumin ≥ 3.5 g/dL as reference, patients with creatinine <6 mg/dL and albumin <3.5 g/dL had a 1.8-fold higher risk of mortality (hazard ratio: 1.75, 95% confidence interval: 1.33-2.30) in twice-weekly and 2.2-fold increased risk of mortality (hazard ratio: 2.21, 95% confidence interval: 1.81-2.70) in thrice-weekly hemodialysis patients, respectively in fully adjusted models adjusted for demographics, comorbidities, and markers of malnutrition and inflammation. A test for interaction showed that there was no significant difference in albumin creatinine mortality associations between twice-weekly and thrice-weekly hemodialysis patients (P-for-interaction = .7667).

Conclusions

Surrogate markers of higher visceral protein and muscle mass combined may confer greatest survival in both twice-weekly and thrice-weekly hemodialysis patients.