Association between long-term hemoglobin variability and mortality in Korean adults: a nationwide population-based cohort study.

Hemoglobin variability is known to be associated with mortality in patients with chronic renal failure and cardiovascular disease. However, the effect of hemoglobin variability on mortality in the general population has not yet been studied. We aimed to investigate the association between hemoglobin variability and mortality using Korean cohort from National Health Insurance Service-Health Screening 2002-2015 database. This study was conducted on 182,757 adults who underwent more than 4 health screenings from 2002 to 2009. Hemoglobin variability was assessed by 3 indices of coefficient of variation (CV), standard deviation (SD), and variability independent of the mean (VIM). Cox proportional hazard regression analysis was performed for each index of quartile groups (Q1-Q4). The hazard ratio and 95% confidence interval^l for all-cause mortality comparing Q2, Q3 and Q4 with Q1 of hemoglobin variability CV in the multivariable adjusted model were 1.07 [0.96-1.20], 1.18 [1.06-1.31] and 1.43 [1.29-1.58] respectively. As the 5% CV, SD, and VIM increased, the hazard ratio for mortality increased by 1.08 [1.06-1.10] in the multivariable adjusted model. Hemoglobin variability is not only important predictor in patients with chronic renal failure and cardiovascular disease but could also be considered as a useful predictor of mortality in the general population.