Using the PedsQL™ 3.0 asthma module to obtain scores comparable with those of the PROMIS pediatric asthma impact scale (PAIS)

Abstract

Background: The National Institutes of Health's Patient-Reported Outcomes Measurement Information System (PROMIS) has developed several scales measuring symptoms and function for use by the clinical research community. One advantage of PROMIS is the ability to link other scales to the PROMIS metric.

Objectives: The objectives of this research are to provide evidence of validity for one of the PROMIS measures, the Pediatric Asthma Impact Scale (PAIS), and to link the PedsQL™ Asthma Symptoms Scale with the metric of the PAIS.

Methods: Descriptive statistics were computed describing the relationships among scores on the PAIS, the PedsQL™ Asthma Symptoms, Treatment, Worry, and Communication Scales, and the DISABKIDS Asthma Impact and Worry Scales for approximately 300 children ages 8-17. A novel linkage method based on item response theory (IRT), calibrated projection, was used to link scores on the PedsQL™ Asthma Symptoms Scale with the metric of the PAIS.

Results: The PAIS exhibited strong convergent validity with the PedsQL™ Asthma Symptoms Scale, and less strong relations with the other five scales. The linkage system uses scores on the PedsQL™ Asthma Symptoms Scale to produce relatively precise score estimates on the metric of the PAIS.

Conclusions: Results of this study provide evidence for the validity of the PAIS, and a method to use scores on the PedsQL™ Asthma Symptoms Scale to estimate scores on the metric of the PAIS, in partial fulfillment of the PROMIS goal to provide a lingua franca for health-related quality of life.

Conflict of interest statement

Conflict of interest Dr. Varni holds the copyright and the trademark for the PedsQL™ and receives financial compensation from the Mapi Research Trust, which is a nonprofit research institute that charges distribution fees to for-profit companies that use the Pediatric Quality of Life Inventory™.

Figures

Fig. 1

The x-axis variable is θ2, the underlying construct measured by the PedsQL Asthma Symptoms Scale, and the y-axis variable is θ1, the underlying construct measured by the PAIS (both in standard units). The correlation between the two latent variables is indicated by the density ellipses around the correlation line. The implied distribution on θ2 for summed scores of 13 and 44 on the PedsQL Asthma Symptoms Scale are shown along the x-axis, along with the corresponding implied distributions on θ1, the PAIS construct along the y-axis