RESUMO
Although immediate pain sensation at the injection site is reported by patients, only limited data on comparison of pain at the injection site between erythropoiesis stimulating agents are available. Therefore, we compared the effect of subcutaneous epoietin-beta on immediate pain sensation to that of subcutaneous darbepoietin-alpha in a double blind, randomized controlled study. Adult patients, aged 18 - 75 years, treated with peritoneal dialysis or with stage 4 chronic kidney disease who in our unit are treated with subcutaneous darbepoietin-alpha for renal anemia for at least 3 months, were eligible for the study. After informed consent, patients received on one day four subcutaneous injections, two in each upper leg, in a fixed sequence, blinded to the patient and blinded to the investigator. Injections contained in a random order single dose epoietin-beta (0,3 ml = 4000 IU), darbepoietin-alpha (0,5 ml = 20 microg) and volume matched saline 0.9% placebo injections. Immediately after the four injections, whilst remaining sitting, the subject was requested to fill out one pain scale (Visual Analogue Scale (VAS)) and to verbally evaluate the pain experience (Verbal Pain Score (VPS)). Finally, the subject was requested to rank the four injections from least to most painful (Treatment Ranking). A total of 42 patients (22 male) participated in the study with a mean age of 56.8 +/- 1.9 years. The average VAS was lower for epoietin-beta (26.8 +/- 4.5 mm) compared to darbepoietin-alpha (58.1 +/- 4.6 mm; p < 0.01). Mean VAS for epoietin-beta did not differ from that of the two placebo saline solutions (0,3 ml 26.3 +/- 4.4 mm; 0,5 ml 18.4 +/- 3.2 mm). Mean VAS for darbepoietin-alpha was significantly higher than placebo (both p < 0.01). Similar observations were obtained for VPS (mean for epoietin-beta 1,3 +/- 0.2 and for darbepoietin-alpha 2.9 +/- 0.2; p < 0.01) and Treatment Ranking (mean for epoietin-beta 2.0 +/- 0.2 and for darbepoietin-alpha 3.2 +/- 0.2; p < 0.01). From the results it can be concluded that subcutaneous epoietin-beta caused statistically significant less pain sensation immediately after injection compared to subcutaneous darbepoietin-alpha . The pain caused by subcutaneous epoietin-beta injection was similar to that caused by placebo control injections whereas subcutaneous darbepoietin-alpha injection was significantly more painful than subcutaneous placebo injections.
