Validity of the St George's respiratory questionnaire at acute exacerbation of chronic bronchitis: comparison with the Nottingham health profile.

The purpose of the study is to compare a generic and a specific quality of life (QoL) instrument in the assessment of QoL in chronic bronchitis. Data from 320 patients were collected at acute exacerbation of chronic bronchitis (AECB), and from 230 patients during a subsequent stable phase (non-AECB), utilising both the specific St George's respiratory questionnaire (SGRQ) and the generic Nottingham health profile (NHP). Patients (maximum n = 200) reported significantly poorer QoL at AECB than at non-AECB for all domains except the SGRQ symptom domain (SRM = 0.02). The SGRQ was more sensitive than the NHP to QoL differences between patients. The correlations between the scores across the two assessments were generally higher for the SGRQ, with the correlations between the NHP and SGRQ being lower at AECB, suggesting that the instruments are measuring different constructs at AECB, with the SGRQ being less responsive to QoL change. Indeed, the NHP was generally more responsive to QoL change in terms of 'risk' and clinical factors, with the SGRQ symptom domain appearing particularly non-responsive. In conclusion, this study suggests that the condition-specific SGRQ, and particularly its symptom domain, is less responsive than the generic NHP to QoL change accompanying AECB. This reflects the construct of the symptom domain which measures chronic bronchitis symptoms over the previous year.