Validity of questions about activities of daily living to screen for dependency in older adults

OBJECTIVE: To determine the criterion validity of the activities of daily living present in functionality questionnaires in older adults for population surveys and to identify which activities are valid to quantify the real daily need for help of this population. METHODS: This is a population sample of older adults stratified by levels of functionality, according to self-perception of dependency in the activities of daily living. Self-perception was compared with the gold standard – direct observation of these activities in the household of older adults by a trained professional, blinded to the answers in the questionnaire. At the visit, it was decided if the older adult needed help to perform any of the activities of daily living for the research. The sensitivity of each activity of daily living was greater when the self-assessment that there was no need for help coincided with the assessment of the professional. Specificity indicates coincidence regarding the need for help in the activities of daily living – coefficients of sensitivity and specificity above 70% were considered as indicative of good validity. RESULTS: Self-assessments showed better sensitivity than specificity – older adults and observers agreed more on daily independency than on dependency. All activities showed sensitivity above 70%. Some activities had low (go shopping: 55%) or very low specificity (brush the hair: 33%). The best specificities were to take a shower and dress up (95.8% for both), among the personal ones, and to use transportation and perform banking transactions (78% for both), among the instrumental ones. CONCLUSIONS: Activities of daily living can be valid indicators of functional dependence. The best coefficients of validity were generally obtained for personal activities. Some activities with good sensitivities and specificities – walk 100 meters, take a shower, and lie down in and get out of the bed – can be used to classify older adults into low, average, and high need for help depending on the affected activities and, therefore, can help in the planning of health services aimed at them.