Development of a patient-reported outcome measure for children with streptococcal pharyngitis.

OBJECTIVE

The objective of this study was to develop a patient-reported outcome measure (Strep-PRO) for assessing symptoms of group A Streptococcus (GAS) pharyngitis from the child's point of view and to present preliminary data on its internal reliability, construct validity, and responsiveness.

METHODS

We selected 8 symptoms for inclusion in the Strep-PRO. We used the Strep-PRO to assess improvement in children who were aged 5 to 15 years and had confirmed GAS pharyngitis. Children completed the scale at study visits and as a diary at home. To evaluate internal reliability, we examined correlations between the items on the scale. To evaluate construct validity, we examined the correlation at entry between Strep-PRO scores and scores on other, previously validated measures of pain and functional status. To evaluate responsiveness, we examined the change in score from enrollment to follow-up. The correlation between the Strep-PRO score and parental assessment of symptoms was also evaluated.

RESULTS

A total of 131 children were enrolled; 113 returned completed diaries. The internal reliability of the scale was high. The magnitude of correlations between Strep-PRO scores and other measures of pain and functional status ranged from 0.39 to 0.63. The responsiveness of the Strep-PRO was very good. The overall level of agreement between child Strep-PRO scores and parental assessment of symptoms was 0.57.

CONCLUSIONS

The scale seems to measure effectively both pain and overall functional status in children with GAS pharyngitis. These data support the use of Strep-PRO as a measure of outcome in future clinical trials.