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.