Hematocrit level and associated mortality in hemodialysis patients

Although a number of clinical studies have shown that increased hematocrits are associated with improved outcomes in terms of cognitive function, redu ced left ventricular hypertrophy, increased exercise tolerance, and improve d quality of life, the optimal hematocrit level associated with survival ha s yet to be determined. The association between hematocrit levels and patie nt mortality was retrospectively studied in a prevalent Medicare hemodialys is cohort on a national scale. All patients survived a 6-mo entry period du ring which their hematocrit levels were assessed, from July 1 through Decem ber 31, 1993, with follow-up from January 1 through December 31, 1994. Pati ent comorbid conditions relative to clinical events and severity of disease were determined from Medicare claims data and correlated with the entry pe riod hematocrit level. After adjusting for medical diseases, our results sh owed that patients with hematocrit levels less than 30% had significantly h igher risk of all-cause (12 to 33%) and cause-specific death, compared to p atients with hematocrits in the 30% to less than 33% range. Without severit y of disease adjustment, patients with hematocrit levels of 33% to less tha n 36% appear to have the lowest risk for all-cause and cardiac mortality. A fter adjusting for severity of disease, the impact of hematocrit levels of 33% to less than 36% is vulnerable to the patient sample size but also demo nstrates a further 4% reduced risk of death. Overall, these findings sugges t that sustained increases in hematocrit levels are associated with improve d patient survival.