Correlation between health-related quality of life using St. George’s Respiratory Questionnaire and pulmonary function testing in Thai patients with chronic obstructive pulmonary disease

Abstract

Background : Chronic obstructive pulmonary disease (COPD) is characterized by progressive worsening of airway obstruction. The patients usually present with cough, breathlessness on and limited activities, which adversely affects their quality of life. Severity of COPD is traditionally classified by using spirometry. However, the relationship between quality of life and lung function parameters is unclear.

Objective : To study the effects of COPD on the health-related quality of life of patients in the Outpatient Clinic, King Chulalongkorn Memorial Hospital (KCMH) using Thai version of the St. George’s Respiratory Questionnaire (SGRQ) and to evaluate correlation of FEV1% predicted value and the SGRQ score.

Methods : A cross-sectional analytic study was conducted in COPD patients who visited at the Outpatient Clinic, King Chulalongkorn Memorial Hospital from 1 August 2008 to 30 April 2009. All cases were diagnosed and staged by clinical features and spirometric results as previously described. Correlation of the SGRQ score and FEV1% predicted was evaluated by Pearson’s Correlation.

Results : Forty COPD patients were enrolled into the study. Sixty percent of the patients were more than 70 years old. SGRQ score in COPD patients was lower than normal, ranged from 1.59 to 85.9 (mean 42.94, SD 24.1). There were weak correlation between the quality of life evaluated by SGRQ scores and FEV1 value (r = -0.368 for total scores, r = -0.326 for symptom scores, r = -0.381 for activity scores and r = -0.305 for impact scores. Note that the higher SGRQ score reflects the worse quality of life). Statistical significance had been shown in all subdomains except impact scores (P = 0.019, 0.04, 0.015 and 0.056 for total scores, symptom scores, activity scores, and impact scores, respectively).

Conclusion : Health-related quality of life measured by the SGRQ has weak correlation with pulmonary function tests in Thai COPD patients.