Background: This study evaluated the validity and reliability of applying the Katz’s Activities of Daily Living(ADL) scale in an Iranian sample of elderly oncologic patients following initial cancer treatment. Materialsand
Methods: The scale was translated with the forward-backward procedure to give an Iranian version. TheADL scale was then applied in a random sample of 400 oncologic patients aged 60 and older following initialcancer treatment. Assessment of the scale stability was twice, with a 14-days (two weeks) interval, to 30 (of the400) eligible elderly cancer patients in March 2012. To measure treatment effects, the index was run with 150patients in a three month recall, following oncology processing. Exploratory and confirmatory factor analysiswas performed for assessment of construct validity of the Katz’s ADL. Reliability was measured with internalconsistency (Cronbach’s alpha co-efficient), and test/retest (Spearman’s r value) of the instrument. Criterionvalidity was evaluated by comparing the Katz with Physical Function (PF) subscale of SF 36. Known-groupvalidity was approved by comparing of Katz’ ADL between quartile groups of PF subscale of SF 36.
Results: Inour study the ADL demonstrated a high degree of internal homogeneity (Cronbach’s alpha 0.923). There was ahigh correlation between scores of two time measurement of Katz’s ADL (p value of two- related- samples testwas 0.3). Construct validity showed a correlation coefficient of 0.572 between the ADL and PF scores. In factoranalysis, 2 factors were extracted. Evidence for the reliability of the questionnaire was good and known groupvalidity was approved by significant differences of ADL score between quartiles of the PF subscale of SF36.
Conclusions: The results suggest that the Iranian version of ADL applied for oncologic older adult patientsfollowing initial cancer treatment is a reliable and a valid clinical instrument and comparable to those reportedin other studies.