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. (J Allergy Clin Immunol 1999;104:364-9.)