Validation of the standardized version of the Rhinoconjunctivitis Quality of Life Questionnaire

BACKGROUND: In the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), the 3 activity questions are selected by the patients themselves. For greater efficiency, a version with standardized activities is required. OBJECTIVE: Our purpose was to develop and validate a standardized version of the RQLQ, the RQLQ(S). METHODS: With use of 5 RQLQ databases, we identified the activities most frequently selected by patients and formulated 3 generic questions that would encompass the majority of these activities. The RQLQ(S) was tested in a 5-week observational study in 100 adults with symptomatic rhinoconjunctivitis. Patients completed the RQLQ(S), the RQLQ, and other measures of health status at baseline and 1 and 5 weeks. RESULTS: The activity domain of the RQLQ(S) consistently gave lower scores than did the activity domain of the RQLQ (P <.001). However, this made very little difference to the overall scores (RQLQ[S] = 2.36 +/- 1.23, RQLQ = 2.43 +/- 1.23), and overall concordance was high (intraclass correlation coefficient = 0.996). In patients whose rhinoconjunctivitis was stable between clinic visits, reliability (reproducibility and ability to discriminate between patients of different impairment) was high for both instruments and almost identical (intraclass correlation coefficient = 0.97). Responsiveness to change was also very similar and good (P <.001). Construct validity (correlation with other index values of health status) was strong for both the RQLQ(S) and the RQLQ. CONCLUSIONS: The RQLQ(S) has strong measurement properties and measures the same construct as the original RQLQ. The choice of questionnaire should depend on the task at hand.