To assess the effect of erythropoietin (EPO) treatment on blood pressure in continuous ambulatory peritoneal dialysis (CAPD) patients, we analyzed in a retrospective study the results of 6 months of EPO treatment in 17 CAPD patients. There were 10 females and 7 males, mean age 52 years, mean duration on CAPD 35 months. They received subcutaneously a mean initial EPO dose of 114 +/- 45 U/kg/week (range 59-209). This dose was adjusted throughout 6 months to achieve and maintain a target Hb of 100 g/L (Hct 30%). Seven of the patients were hypertensive before starting EPO treatment. Fifteen patients (88.2%) achieved the target hemoglobin. For all subjects (n = 17) there was a significant increase in lying mean blood pressure (MBP) from 93.8 +/- 10.0 to 105.2 +/- 14.4 mmHg (p = 0.0024). Four patients required an increase in their antihypertensive medication, and 4 were not treated before we started antihypertensive treatment (Group I). This group represents 46% (8/17) of the patients. There was no change in the antihypertensive medication status of the remaining 9 patients (Group II). The baseline lying MBP was not significantly different for the two groups (98.8 +/- 9.8 mmHg vs 96.1 +/- 7.2 mmHg). The mean weekly dose of EPO during the first 3 months was higher in Group I (126 vs 100 U/kg) and conversely was lower during the last 3 months (mean dose 108 vs 117 U/kg).(ABSTRACT TRUNCATED AT 250 WORDS)