A randomised, cross-over study comparing injection site pain with subcutaneous epoetin beta and subcutaneous darbepoetin alfa in patients with chronic kidney disease

Objective: To compare injection site pain of subcutaneous (sc) epoetin beta and darbepoetin alfa in adult patients with chronic kidney disease. Research design and methods: This was a multi-centre, randomised, two-arm, single-blind, cross-over study. Patients were randomised to receive weekly sc darbepoetin alfa 30 μg or weekly sc epoetin beta 6000 IU for 2 weeks and were then crossed over to the alternative treatment for 2 weeks. Injection site pain was assessed using a 10 cm ungraduated visual analogue scale (0 = no pain, 10=worst pain) and a six-point verbal rating scale. Patient preference for treatment was also assessed. Trial registration: http://clinicaltrials.gov/(NCT00377481). Results: All randomised patients (N=48) completed the study. The sample comprised 29 chronic kidney disease patients (Stage 3 or Stage 4), 11 peritoneal dialysis patients and 8 renal transplant patients. Patients perceived significantly less pain with epoetin beta than darbepoetin alfa, using the visual analogue scale (relative pain score=2.75, darbepoetin alfa:epoetin beta, 95% Cl: 1.85, 4.07; p<0.0001) and the verbal rating scale (median: 0.5, 95% Cl: 0.5, 1.0 vs. median: 1.5, 95% Cl: 1.0, 2.0; p<0.0001). Epoetin beta was preferred by significantly more patients (65%) than darbepoetin alfa (10%) (p<0.001); 25% of patients reported no preference. Conclusions: Limitations included lack of an epoetin alfa comparator and limited blinding (patients were blinded to treatment, however, an unblinded nurse administered treatment). We show that sc injection of epoetin beta is significantly less painful than darbepoetin alfa and patient preference for epoetin beta confirms that the difference is clinically meaningful.