American translation, modification, and validation of the St. George's Respiratory Questionnaire

Background: The St. George's Respiratory Questionnaire (SGRQ) is a 50-item health status survey specific for chronic obstructive pulmonary disease (CO PD) and other respiratory diseases that is available in British English but not American English. The SGRQ's symptom-reporting component requires a 1- year reporting period, which may be too long for reliable and accurate pati ent recall. Objectives: The objectives of the present study were to translate the SGRQ from British to American English, modify the reporting period of the sympto m-reporting component from 1 year to 1 month, and assess the reliability, v alidity, and sensitivity to change of this translated modified version in a sample of patients with COPD. Methods: Based on input from American patients with COPD and health profess ionals, the SGRQ was translated into American English (SGRQ-A) and then tra nslated back to British English. For SGRQ-A reliability and validity studie s, patients were asked to report symptoms experienced over 1 year (reportin g period in the original SGRQ) and 1 month (modification made to SGRQ-A). W e evaluated 102 patients with COPD (50% female; mean age, 68 years; mean fo rced expiratory volume in 1 second [FEV1], 1.01 L) at an administrative ses sion before and after completion of a pulmonary rehabilitation program. The SGRQ-A, Chronic Respiratory Disease Questionnaire (CRQ), 36-Item Short For m Health Survey (SF-36), 6-minute walk (6MW), Medical Research Council (MRC ) Dyspnea scale, and pulmonary function tests (FEV1 and % predicted FEV1) w ere used in the assessment battery. Results: The SGRQ-A showed good agreement with the original SGRQ when trans lated back to British English. Internal reliability (Cronbach alpha) was >0 .70 for all SGRQ-A components except the 1-year symptom-reporting component . Test-retest intraclass correlations were 0.795 to 0.900. Construct validi ty was strengthened when all SGRQ-A components (except 1-year symptoms and most 1-month symptoms) correlated (P less than or equal to 0.01) with the M RC Dyspnea scale, 6MW, all SF-36 concept scores, and 80% of CRQ domains (r = 0.30-0.72). Discriminate validity was demonstrated when all components of the SGRQ-A with the modified 1-month symptom-reporting period were shown t o discriminate better between disease-severity groups (based on patient sel f-reports of disease severity) than did pulmonary function tests and the 6M W. Responsiveness of the SGRQ-A to change in health status was demonstrated when scores on the Symptoms-1 month and Total-1 month components detected significant improvements in patients' health status (P = 0.02 and P = 0.04, respectively). Conclusion: The SGRQ-A with a modified I-month symptom-reporting period dem onstrated reliability and validity in this sample of patients with COPD.