The Factorial Structure of the Amsterdam Preoperative Anxiety and Information Scale in Parents of Pediatric Surgical Patients: An Item Response Theory Analysis.

BACKGROUND

Preoperative anxiety is a common experience among patients undergoing surgery. The Amsterdam Preoperative Anxiety and Information Scale (APAIS) is a short questionnaire designed to assess anxiety related to anesthesia and surgery, as well as patient's need for preoperative information (anesthesia and surgery). Despite its widespread use, comprehensive psychometric analyses using modern latent variable models remain limited.

METHODS

In this cross-sectional psychometric analysis nested within a larger observational study, parents of children undergoing surgery answered the APAIS before their children's surgery. Responses were analyzed using item response theory (IRT) methods.

RESULTS

Of the 477 parents who participated in the survey, 476 completed the APAIS. Participant's age ranged from 24 to 65 years (female: 76.1%). None of the tested models (one- to three-factor structures using different IRT-models) showed acceptable fit across all indices (root mean square error of approximation [RMSEA] < 0.08, Tucker-Lewis index [TLI] ≥ 0.90, comparative fit index [CFI] ≥ 0.90). For the originally proposed factorial structure using a graded response model (RMSEA: 0.26, TLI: 0.82, CFI: 0.91), reliability was high (r > 0.8) for the middle area of -1.4 to +2.7 logits for anxiety and -1.4 to +1.8 logits for need for information. The magnitude of all statistically significant differential item functioning (DIF) effects was below the predefined threshold for clinical relevance.

CONCLUSIONS

None of the previously proposed factorial structures met the criteria for good model fit. The best-fitting model was the original two-factor structure, which showed poor model fit regarding RMSEA and acceptable model fit regarding CFI for all test models. TLI was acceptable for the partial credit model only. Further studies with larger sample sizes and the application of modern psychometric methods, such as IRT, are needed to clarify the factorial structure of the APAIS.