Comparison of Instrumental Activities of Daily Living assessment by face-to-face or telephone interviews: a randomized, crossover study

Background: The functional autonomy assessment is essential to manage patients with a neurodegenerative disease, but its evaluation is not always possible during a consultation. To optimize ambulatory autonomy assessment, we compared the Lawton Instrumental Activities of Daily Living (IADL) questionnaire collected by telephone and face-to-face interviews. Methods: A randomized, crossover study was carried out among patients attending a memory clinic (MC). The IADL questionnaire was collected for patients during telephone and face-to-face interviews between nurses and patients' caregivers. The agreement between the two methods was measured using the proportion of participants giving the same response, Cohen's kappa, intraclass correlation (ICC) coefficient, and Bland and Altman method. The associations between patients' characteristics, events occurring between the two assessments, and agreement were assessed. Results: Among the 292 patients (means +/- SD age 81.5 +/- 7, MMSE 19.6 +/- 6, 39.7% with major neurocognitive disorders) analyzed, the proportion of agreement between the two modes was 89.4% for the total IADL score. Weighted kappa coefficient was 0.66 and ICC score was 0.91 for total IADL score. The mean difference between the IADL score by telephone or face-to-face was 0.32. Overall, 96.9% of measures lay within the 95% limits of agreement. The occurrence of fall was less likely associated with the probability to lie within the 95% limits of agreement (OR = 0.07 [0.02-0.27]). Conclusion: The administration of IADL by telephone with the caregiver appears to be an acceptable method of assessment for MC patients compared to face-to-face interview. The events such as falls which could occur in a time close to the evaluation should be reported.