Recombinant human erythropoietin improves health-related quality of life in patients with rheumatoid arthritis and anaemia of chronic disease; utility measures correlate strongly with disease activity measures
Treatment with recombinant human erythropoietin (r-hu-Epo) in patients with rheumatoid arthritis (RA) and anaemia of chronic disease (ACD) resulted in improvement of both anaemia and disease activity. Utilities represent a generic and comprehensive quality of life measure, capable of integrating domain-specific information into one overall value which a patient assigns to his state of health. Therefore, the effect of r-hu-Epo
on quality of life was studied by measuring utilities, derived from the rating scale and standard gamble, in a 52-week placebo-controlled randomised double-blind study with r-hu-Epo in 70 patients with active RA and ACD. Furthermore, the relation between anaemia as assessed by haemoglobin levels (Hb), disease activity as assessed with the Disease Activity Score (DAS), and utilities was investigated. Compared to the placebo group, significant improvement of Hb (P < 0.001), DAS (P = 0.01) and rating scale utilities (P = 0.002), but not of standard gamble utilities, was observed in the Epo group. Rating scale utilities correlated strongly with DAS (r = -0.47, P < 0.01), Hb (r = 0.37, P < 0.01) and changes in both DAS (r = -0.74, P < 0.01) and Hb (r = 0.44, P < 0.01). Both DAS and Hb contributed significantly to the variance in rating scale utilities (21% and 3% respectively) and to changes in rating scale utilities (43% and 3% respectively). Standard gamble utilities correlated less well with clinical disease variables than rating scale utilities did. These results indicate, that r-hu-Epo improves utility-derived health-related quality of life, most probably by improving both disease activity and anaemia. Utilities, particularly rating scale utilities, correlated well with conventional disease activity variables and proved sensitive to change. Utilities may be a useful tool for investigating quality of life in RA-patients.