Construction of the pediatric asthma impact scale (PAIS) for the patient-reported outcomes measurement information system (PROMIS)

Background. Recently, the National Institutes of Health Roadmap for Medical Research initiative led a large-scale effort to develop the Patient-Reported Outcomes Measurement Information System (PROMIS). PROMIS's main goal was to develop a set of item banks and computerized adaptive tests for the clinical research community. Asthma, as the most common chronic childhood disease, was chosen for a disease-specific pediatric item bank. Objectives. The primary objective of this research is to present the details of the psychometric analyses of the asthma domain items. Methods. Item response theory (IRT) analyses were conducted on a 34-asthma item bank. Test forms containing PROMIS Pediatric Asthma domain items were completed by 622 children ages 8 to 12. Items were subsequently evaluated for local dependence, scale dimensionality, and differential item functioning. Results. A 17-item pool and an 8-item short form for the new PROMIS Pediatric Asthma Impact Scale (PAIS) were generated using IRT. The recommended 8-item short form contains the item set that provides the maximum test information at the mean (50) on the T-score metric. If more score precision is required, the complete 17-item pool is recommended and may be used in toto or as the basis of a computerized adaptive test (CAT). A shorter test form can also be created and scored on the same scale. Conclusions. The present study presents the PROMIS Pediatric Asthma Impact Scale (PAIS) developed with IRT, and provides the initial calibration data for the items.