Background: Anemia is a major contributor to morbidity and mortality in chronic dialysis patients. The K/DOQI guideline recommends the target hemoglobin of 11-12 g/dl (hematocrit of 33-36%). However, the appropriate hematocrit level for Thai hemodialysis patients has been controversial.
Objective: To investigate the influence of anemia on mortality in Thai chronic hemodialysis patients who initiated their dialysis from 1999 through 2003.
Material and Method: The data from the Thailand Renal Replacement Therapy Registry who has conducted an annual report of chronic dialysis patients throughout Thailand since 1997 was used. Data of twice- and thrice-weekly hemodialysis patients who had recorded hematocrit from 1999 through 2003 were processed and confirmed before final analysis. Records of 3,211 hemodialysis patients from 301 centers were included.
Result: The original kidney diseases were diabetes mellitus (31.5%) and hypertension (20.9%). Most patients received twice-weekly hemodialysis (86.3%). The mean hematocrit was  29.35.5%. Most patients (72.8%) had hematocrits of less than 33%. Kaplan-Meier analysis showed patients with hematocrit of ?33% or more had better survival than patients with hematocrits of less than 33% (p <0.01). Patients with hematocrits of less than 27, 27-29.9, 30-32.9 and 36% or more had mortality risks of 1.90 (95% CI: 1.31-2.76, p <0.01), 2.10 (95% CI: 1.42-3.09, p <0.01), 1.74 (95% CI: 1.18-2.56, p <0.01) and 1.174 (95% CI: 0.73-1.90, p = 0.51) respectively, compared to those with hematocrit of 33-35.9%.
Conclusion: The best survival can be achieved in Thai patients with hematocrits of at least 33%.

Keywords: Anemia, Hemodialysis, Mortality