['Hemoglobin variability in hemodialysis patients treated with erythropoiesis-stimulating agents has been used to evaluate mortality and comorbidity. Different outcomes have been reported in American and European hemodialysis patients. There are, however, few studies of the effects of hemoglobin variability in peritoneal dialysis patients.', 'We investigated hemoglobin variability in 363 peritoneal dialysis patients over 2 years to evaluate mortality and the association with comorbidity, peritonitis, and hospitalization. The hemoglobin of all patients selected for the study had been monitored for at least 6 months (April 2008 to September 2008). We assessed hemoglobin variability as fluctuations from the target hemoglobin level (11-12.5 g/dL). We defined the following 6 patient groups on the basis of hemoglobin patterns: consistently low (< 11 g/dL), consistently target range (11-12.5 g/dL), consistently high (> 12.5 g/dL), low-amplitude fluctuation with low hemoglobin levels, low-amplitude fluctuation with high hemoglobin levels, and high amplitude fluctuation.', 'Only 2% of patients maintained a stable hemoglobin level within the target range and 46.8% of patients exhibited consistently low hemoglobin levels. After 2 years of observation, there was no difference in mortality as assessed by Kaplan-Meier analysis. There were also no differences in peritonitis and hospitalization between the 6 groups. However, the length of hospital stay was longer in the high amplitude fluctuation group (p = 0.008).'] Does hemoglobin variability predict mortality in peritoneal dialysis patients?