The aims of the present study were to determine the prevalence of depression in our dialysis patients, to detect the most powerful variables associated with depression, and to determine the role of depression in prediction of mortality. The prospective follow-up study of 128 patients (77 HD and 51 CAPD, 65 male, aged 53.8 +/- 13.5 years, dialysis duration 64.7 +/- 64.8 months) was carried out over 36 months. Depression by the Beck Depression Inventory-BDI-II score, laboratory parameters (hemoglobin, serum albumin and creatinine concentration), immunological status (cytokines and hsCRP), comorbidity by Index of Physical Impairment (IPI) and adequacy of dialysis by Kt/V were monitored. The overall prevalence of depression in the dialysis patients (BDI score > or = 14) was 45.3%, and 28.2%, respectively, for moderate and severe depression (BDI > or = 20). The most powerful variable associated with depression was IL-6, but associations with albumin, hemoglobin, creatinine and IPI score were also found. During the follow-up period 36 patients died, 7 patients left the cohort and 2 patients were transplanted. If IPI score was not included in the multivariate Cox analysis, the BDI score remained one of the best predictors of mortality along with albumin. In conclusion, because of the close association of depression with inflammation, malnutrition, and cardiovascular mortality, it could be speculated that depression is one branch of the MIA (malnutrition, inflammation, atherosclerosis) syndrome.