Validation of the PAINAD-K Scale for Nonverbal Pain Assessment in the Post Anesthesia Care Unit

Purpose: This study aimed to verify the reliability and validity of the Pain Assessment in Advanced Dementia Scale-Korean version (PAINAD-K) for assessing pain in patients unable to communicate in the post-anesthesia care unit (PACU).Methods: The study included 205 patients, aged >65 years, admitted to the PACU following general surgery. Reliability was assessed using Cronbach’s ⍺, test-retest, intraclass correlation coefficient (ICC), and kappa coefficients. Criterion validity was evaluated with concurrent validity, and receiver operating characteristic (ROC) analysis assessed sensitivity and specificity. Convergent and discriminant validity were analyzed to verify the construct of the scale.Results: The Cronbach’s ⍺, ICC, and test-retest correlation values were .78, .95~.98, and .56~.74, respectively, indicating good reliability. At baseline, the correlation coefficient was .93 with the Algoplus scale in the non-communicative group and .82 with the numeric rating scale in the communicative group. Further establishing criterion validity in the nonverbal group, the area under the ROC curve was 0.995 (sensitivity=98.4%, specificity=97.5%) at baseline and .95 (sensitivity=96.4%, specificity=93.2%) at the 30-minute follow-up. The correlation coefficient with the Critical-Care Pain Observation Tool was .69~.96, showing convergent validity, and there was a significant interaction effect between time and group, indicating discriminant validity.Conclusion: The study findings suggest that the PAINAD-K is a psychometrically valid scale for assessing pain in PACU patients aged >65 years who are unable to communicate.