Different evaluations of the health related quality of life in dialysis patients

BACKGROUND: Sometimes patients on dialysis treatment cannot express their health-related quality of life (HRQoL); and therefore, it is necessary to use the assessment made by their carers. The purpose of this study was to evaluate the agreement between dialysis patients' HRQoL and the assessment made by their carers, and to investigate which variables were associated with the differences found. METHODS: Two hundred and twenty-two pairs of patients and carers were selected from 14 dialysis units. Patients' HRQoL was evaluated by the patients themselves and by their family carer (FAM), nurse (NUR) and physician (PH) using the Karnofsky scale (KS) and the EuroQOL5D (EQ5D) scale. Patients and their family carers answered the Medical Outcome Survey 36-Item Short Form Health Survey (SF-36), and the family carers answered the Zarit burden interview. Physicians scored the patients' comorbidity index and nurses evaluated the Barthel index (BI). RESULTS: The intraclass correlation coefficients (ICC) between the ratings provided by patients and their carers were: KS: 0.80(FAM), 0.76(NUR) and 0.62(PH); EQ5D: 0.42(FAM), 0.48(NUR) and 0.29(PH). The agreement between the EQ5D dimension scores varied from moderate for mobility and self-care to insignificant for pain and anxiety/depression. The variables associated to the size of the differences found were the Zarit burden interview score and the mental component score (MCS) (SF-36) of the carer, the physical component score (PCS) (SF-36), the BI score and patient comorbidity, and the physician's age and experience. CONCLUSIONS: Family carers and health care providers of dialysis patients are reasonably aware of the patient's level of function and well being and can be useful sources of proxy HRQoL information. Nevertheless, discrepancies can occur, depending in part on the different characteristics of patients and their caregivers.