Evaluation of instrumental activities of daily living in Greek patients with advanced cancer

Translation of the instrumental activities of daily living (IADL) was carried out and its psychometric properties were assessed in a Greek sample of patients with advanced cancer. The scale was translated with the forward-backward procedure into the Greek language. It was initially administered to 136 advanced cancer patients. To assess reliability, it was administered to 45 patients 3 days later. To assess the effect of treatment, 75 patients were studied. The patients also completed the Eastern Cooperative Oncology Group (ECOG) performance status and the linear analogue scale assessment (LASA) quality of life (QoL) scale. Confirmatory factor analysis of the IADL was carried out. Reliability was assessed in terms of internal consistency (Cronbach's alpha) and test-retest correlation (Pearson and ICC) of the IADL scale. Construct validity was assessed through correlation of IADL with ECOG and LASA QoL scores. Confirmatory factor analysis yielded a single-factor model. The homogeneity of the instrument proved to be satisfactory (alpha was 0.88 for men and 0.83 for women). Test-retest reliability was also satisfactory (P < 0.0005). High correlation with ECOG (men, r=-0.87; women, r=-0.85) and LASA QoL (men, r=0.55; women, r=0.53) was observed. The Greek version of the IADL in cancer patients treated in a palliative care unit is a reliable and valid clinical instrument.