Development and validation of the Drug Hypersensitivity Quality of Life Questionnaire

Background: The impact of drug hypersensitivity has never been considered from the patient's perspective, and no questionnaire is currently available for this purpose. Objective: To develop and validate a questionnaire specifically designed for the assessment of quality of life in patients with drug hypersensitivity entitled the Drug Hypersensitivity Quality of Life Questionnaire (DrHy-Q). Methods: During the development procedure, an initial questionnaire of 34 items was generated and administered to 70 patients; the 20 most important items were detected and converted into questions evaluated with a 5-point Likert scale. This provisional questionnaire then underwent a validation procedure to assess its psychometric properties. The DrHy-Q and the Psychological General Well-Being Index (PGWBI) were completed by 365 patients (67.5% female; mean [SD] age, 40 [15] years). Results: Statistical analysis revealed a 1-dimensional structure for the DrHy-Q that explained up to 50.7% of the total variance and showed good levels of internal consistency for the extracted factor (Cronbach α = 0.928). The correlations between the DrHy-Q and the PGWBI scores were low. However, the DrHy-Q scores of patients who experienced anaphylactic shock were significantly higher than the scores from patients with other reactions (analysis of variance; F = 5.991; df = 4; P <.001). The test-retest associations were good (R = 0.995; P <.001). Conclusions: DrHy-Q met the standards for construct validity, internal consistency, and reliability, indicating that it is appropriate for use alone or in combination with other patient-reported outcome questionnaires to explore the subjective experiences of patients with drug hypersensitivity.