Despite the long experience in erythropoietin (EPO) treatment in end-stage renal disease (ESRD)-related anemia, controversy remains as to whether EPO treatment of anemia can improve the quality of life (QL) in elderly ESRD patients, as it does in younger ones. We conducted a prospective study of 57 stable patients on hemodialysis who started on EPO treatment. A control group of 29 hemodialysis patients not requiring EPO was simultaneously studied. Diabetic patients and patients with severe comorbidity were excluded. Quality of life was assessed at baseline before EPO treatment and after 3 and 6 months of follow-up, using the Karnofsky scale (KS) and the Sickness Impact Profile (SIP) questionnaire. A high KS score and a low SIP score indicate better QL. Erythropoietin patients were stratified into two age groups: <60 years (n = 34) and > or = 60 years (n = 23). In the EPO group mean hematocrit values improved from 21 percent at baseline to 29 percent at the sixth month; mean KS scores increased from 68 +/- 1.8 to 81 +/- 1.5 (P < 0.0001) and the mean global score of SIP decreased from 19.8 +/- 1.6 to 13.5 +/- 1.2 (P < 0.0001). No significant changes were observed in the control group. Elderly patients in the EPO group showed improved KS scores, from 61 +/- 1.5 to 75 +/- 2.5 (P < 0.0001), and the global score of SIP decreased from 27.7 +/- 2.1 to 20 +/- 1.8 (P < 0.001). Younger patients had improvement of their KS scores, from 73 +/- 2.5 to 85 +/- 1.5 (P < 0.0001), and the global score of SIP decreased from 14.5 +/- 1.9 to 9.1 +/- 1.2 (P < 0.001). No relationship was found between age groups and improvement in QL indicator scores. On regression analysis, a poor basal QL score was related to higher QL improvement under EPO treatment, and final hematocrit was positively related to global SIP improvement. Treatment of ESRD-related anemia with EPO significantly improved the QL of hemodialysis patients. Quality of life in elderly patients improved as much as in younger patients, thereby fully justifying the use of EPO for the elderly.