Psychosocial factors, behavioral compliance and survival in urban hemodialysis patients

Background. The medical risk factors associated with increased mortality in hemodialysis (HD) patients are well known, but the psychosocial factors that may affect outcome have not been clearly defined. Psychosocial factors could affect mortality through interaction with patients' nutrition or their compliance with the dialysis prescription. We conducted a prospective, longitudinal, multicenter study of urban HD patients to determine the contribution of compliance and psychosocial factors to patient survival. Methods. Patients were assessed using indices of social support, patient's assessments of their well-being, including illness effects (IEQ), and satisfaction with life (SWLS), the Beck Depression Inventory (BDI), serum albumin concentration, Kt/V and protein catabolic rate (PCR). Behavioral compliance was measured three ways: percent time actually dialyzed per treatment compared to prescribed time (shortening behavior); percent sessions attended (skipping behavior) and total integrated time compliance (% TCOMP). A severity index, previously demonstrated to be a mortality marker, was used to grade medical comorbidity. The type of dialyzer the patient was treated with was noted. A Cox proportional hazards model, controlling for age, medical comorbidity, albumin concentration and dialyzer type was used to assess relative mortality risk of variations in psychoscial factors and behavioral compliance. Results. A total of 295 patients (60.8% of those eligible) agreed to participate. The mean (+/- SD) age of our population was 54.6 +/- 14.1 year, mean PCR was 1.06 +/- 0.27 g/kg/day, and mean Kt/V 1.2 +/- 0.4, suggesting the patients were well nourished and adequately dialyzed. The patients' mean BDI was 11.4 +/- 8.1 tin the range of mild depression). Patients' SWLS was similar to that of a group of patients without chronic illness. After a 26 month mean follow-up period, higher levels of perceived social support, improved perception of the effects of illness and increased behavioral compliance were significantly associated with decreased relative mortality risk (0.8, 0.77, and 0.79, respectively), controlled for variations in patients' age, severity of illness, serum albumin concentration and dialyzer type. Variations in depression and Kt/V were not predictors of mortality during the observation period. Conclusions. Lower levels of social support, decreased behavioral compliance with the dialysis prescription, and increased negative perception of the effects of illness are independently associated with increased mortality in ESRD patients treated with HD. The effects are of the same order of magnitude as medical risk factors. Such effects may be attributable to a relationship between a patients' perception of social support and effects of illness and behavior, with other factors such as the provision of better medical care in patients with larger social networks. The mechanism underlying the relationship of psychosocial factors and compliance and survival, and the effect of interventions to improve perception of illness, and increase social support and compliance with the dialysis prescription in HD patients should be studied.