Comparison of the 36-Item WHODAS 2.0 Functional Assessment in Older Adults by Face-to-Face or Telephone Interviews: A Randomised Crossover Study

<b>Background/Objectives:</b> With the expansion of telemedicine, it is essential to determine whether the telephone administration of validated disability measures yields results equivalent to face-to-face interviews in older adults. We aimed to compare the agreement between face-to-face and telephone administration of the 36-item WHODAS 2.0 in a community-dwelling population aged ≥60 years. <b>Methods:</b> The study was a randomised, open-label, cross-over design involving 239 people aged ≥60 from south-eastern Poland. Participants were randomly assigned to two groups: G1 (face-to-face interview first, then telephone interview) and G2 (in the reverse order). The interval between interviews was an average of 14.3 ± 1.3 days. The full version of WHODAS 2.0 (excluding domain D5.2) was used. Cohen's kappa coefficient (κ), intraclass correlation coefficient (ICC) and Bland-Altman analysis were used to assess the consistency of the results. <b>Results:</b> A total of 203 individuals completed both surveys. The agreement between responses for individual items ranged from 85.71% to 98.03% (κ = 0.788-0.947). The WHODAS 2.0 total score showed very high agreement between face-to-face and telephone interviews (ICC = 0.986). All domains showed high or very high agreement (ICC = 0.953-0.967). Bland-Altman analysis confirmed high agreement-only 5.42% of results fell outside the 95% limits of agreement. <b>Conclusions:</b> Telephone interviews are a reliable alternative to face-to-face interviews when using the 36-item WHODAS 2.0 in older adults. Both methods provide comparable and reliable results, confirming the usefulness of telephone interviews in clinical practice and screening, especially when access to in-person healthcare is limited.