Relationship between SGRQ score and pulmonary function and its influencing factors in patients with chronic obstructive pulmonary disease

Abstract

To study the correlation and influencing factors between the St. George respiratory questionnaire (SGRQ) and lung functions in chronic obstructive pulmonary disease (COPD) patients. Sixty-three stable COPD patients received pulmonary function tests and SGRQ. A correlation analysis of the results was performed. They were divided into two groups according to GOLD (global initiative for chronic obstructive lung disease) classification scheme, 32 patients were in stage II (moderate) and 31 in stages III and IV (severe & very severe). And the inter-group SGRQ scores were compared. According to age, they were divided into < 70 years group (n = 31) and ≥ 70 years group (n = 32). The correlations between the SGRQ score and pulmonary functions were analyzed in different age groups. Thirty-six patients willing to participate in treatment and a 3-month follow-up were randomly divided into two groups of treatment with either salmeterol/fluticasone (50 µg/500 µg) (n = 18) or salbutamol/ipratropium bromide (120 µg/21 µg) (n = 18). The post-therapeutic changes of SGRQ score and pulmonary functions were analyzed. There were no significant differences in SGRQ total score and all section score between two groups according to GOLD classification scheme. There were mild to moderate correlations in the < 70 years group between lung functions including FVC%, FEV(1)%, FEFMAX%, SVC% and the SGRQ score including total score, symptoms section score and activity section score. The range of correlation coefficients was -0.341 to -0.534. However, the score only had some correlation with IC% in the ≥ 70 years group. Compared with the salbutamol/ipratropium bromide treatment group, the SGRQ score of the salmeterol/fluticasone treatment group decreased significantly after therapy (P = 0.001). Influenced by age, the SGRQ score can be used to evaluate the clinical efficacy of medications in COPD patients.