Reliability of the Brazilian version of the Scale of Instrumental Activities of Daily Living

Abstract

Objective: To analyze the reliability of the Scale of Instrumental Activities of Daily Living (IADL) developed by Lawton and Brody and adapted to Brazilian context. Methods: A cross-sectional analytical study, with 16 women from groups of acquaintanceship, aged 60 to 89 years. In data collection, an individual interview was applied to assess the functional condition of the elderly and the accomplishment of strength testing of upper and lower limbs. Procedures of descriptive and inferential statistics were used for data analysis, by using the correlation intra-class index for obtaining the agreement among the tests for the same examiner (reliability) and for different evaluators (objectivity). The concurrent validity was obtained using Spearman’s correlation for the comparison of self-reported measures and those obtained by strength tests. We established a significance level of 5% with a confidence interval of 95%. Results: Concerning the stability of the measures, they can be classified as almost perfect agreement, both for the reliability (Ricc=0.89) as for the objectivity (Ricc=0.80). In concurrent validity, we observed a moderate relationship between the strength of upper limbs and the referred functional condition (rho=0.53); yet the relationship was not significant regarding the strength of lower limbs. Conclusions: The analysis of the data allows us to affirm that the scale of IADL presents satisfactory psychometric indexes. However, the concurrent validity evidenced that the scale only presents agreement in reference to the force of upper limbs.