Portuguese adaptation and psychometric validation of the Osteoporosis Knowledge Assessment Tool in community-dwelling adults

BACKGROUND: Given the critical role of knowledge in prevention and management of osteoporosis and osteoporotic fractures, a culturally adapted instrument to assess osteoporosis-related knowledge among citizens is essential for patient education. AIM: This study aimed to translate, culturally adapt, and psychometrically validate the Osteoporosis Knowledge Assessment Tool (OKAT) for Portuguese adults aged 50 years and older. METHODS: The study involved two phases: translation and cross-cultural adaptation, and evaluation of measurement properties. An expert committee developed a pre-final Portuguese OKAT, which was tested in adults aged 50-74 years, recruited from primary care and from a blood donation centre. Reliability was assessed via internal consistency (α, ω, KR-20), test-retest reproducibility (r, ICC), and item-level agreement (Cohen's Kappa). Item difficulty, discrimination, and readability were also evaluated. Known-groups validity was examined by comparing scores across sex, age, education, and prior osteoporosis diagnosis. RESULTS: Phase A identified five items with semantic or conceptual challenges, resolved through expert consensus. In phase B, 153 participants (mean age 62 ± 7 years; 54% female) completed the Portuguese OKAT, showing borderline acceptable to acceptable internal consistency (α = 0.698; ω = 0.700; KR-20 = 0.698) and good test-retest (n = 20) reliability (ICC = 0.84; r = 0.84; Cohen's Kappa = 0.375-0.89, with four items yielding non-computable or negative values). Item difficulty and discrimination were appropriate, and readability was suitable (Flesch Reading Ease = 68.35). Women had statistically higher knowledge scores, but no significant differences were found for age, education, or prior diagnosis groups. CONCLUSIONS: The Portuguese version of OKAT demonstrated generally acceptable psychometric performance, supporting its use in adults aged ≥50y. Future research should confirm these findings in more diverse and representative populations.