The study convincingly validates the OPTIMAL-confidence scale; however, the high percentage of “not applicable” responses for items like squatting, kneeling, and bending raises concerns about the questionnaire’s comprehensiveness across diverse patient profiles. Could the authors elaborate on how these missing responses were accounted for in the analysis and whether they considered adapting the questionnaire to accommodate varying functional capacities? The study focuses predominantly on primary care settings in Spain; could the findings differ in populations with distinct cultural or healthcare contexts?
