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.