Prevalence of co-morbidity in different European RRT populations and its effect on access to renal transplantation

Background. This study compared the prevalence of co-morbidity in patients starting renal replacement therapy (RRT) between European countries and further examined how co-morbidity affects access to transplantation. Methods. In this ERA-EDTA registry special study, 17907 patients from Austria, Catalonia (Spain), Lombardy (Italy), Norway, and the UK (England/Wales) were included (1994-2001). Co-morbidity was recorded at the start of RRT. Results. The prevalence of co-morbidity was: diabetes mellitus (DM) (primary renal disease and co-morbidity) 28%, ischaemic heart disease (IHD) 23%, peripheral vascular disease (PVD) 24%, cerebrovascular disease (CVD) 14% and malignancy 11%. With exception of malignancy, the prevalence of co-morbidity was highest in Austria, but differences were small among other countries. With exception of DM, males suffered more often from co-morbidity than females. In general, the percentage of haemodialysis was higher in patients with co-morbidity, but treatment modality differed substantially between countries. Using a Cox regression with adjustment for demographics, country, year of start and other co-morbidities, the presence of each of the co-morbid conditions made it less likely [RR; 95%CI] to receive a transplant within 4 years: DM [0.79; 0.70-0.88], IHD [0.59; 0.50-0.70], PVD [0.57; 0.49-0.67], CVD [0.49; 0.39-0.61], and malignancy [0.32; 0.24-0.42]. The age, gender and year of start adjusted relative risk [95%CI] to receive a renal transplant within 4 years ranged from 0.23 [0.19-0.27] for Lombardy (Italy) to 3.86 [3.36-4.45] for Norway (Austria = reference). These international differences existed for patients with and without co-morbidity. Conclusions. The prevalence of co-morbidity was highest in Austria but differences were small among other countries. The access to a renal graft was most affected by the presence of malignancy and least affected by the presence of DM. International differences in access to transplantation were only partly due to co-morbid variability.