Canonical correlation analysis of factors that influence quality of life among patients with chronic obstructive pulmonary disease based on QLICD-COPD (V2.0)

Background The Quality of Life Instrument for Chronic Diseases (QLICD)-COPD (V2.0) was designed to assess the health condition of patients with chronic obstructive pulmonary disease (COPD). The objective of this study was to evaluate the quality of life (QOL) of patients, the influential clinical factors and the relationships between QOL and clinical objective indicators. Methods Two hundred and sixty-one inpatients with COPD in the acute exacerbation stage were evaluated using the QLICD-COPD (V2.0) and data on clinical objective indicators were collected. The relationships between QOL and the clinical objective indicators were determined using canonical correlation analysis. Results The standardised scores for the patients in four domains, namely, physical function, psychological function, social function and a disease-specific module, were 49.00 +/- 12.91, 59.89 +/- 13.51, 68.59 +/- 11.94 and 51.84 +/- 13.58, respectively. The total score for the QOL of patients was 57.17 +/- 10.26. Two pairs of canonical variables were statistically significant (r(1)=0.35, p<0.0001; r(2)=0.26, p<0.05). These variables accounted for 45.8% and 33.8% of the variance, respectively. The levels of total protein, albumin, serum sodium and alkaline phosphatase and the percentages of neutrophils and lymphocytes were correlated with the QOL, with correlation coefficients ranging from -0.435 to 0.675. Conclusion Clinicians should pay close attention to the levels of total protein, albumin, serum sodium and alkaline phosphatase and the percentages of neutrophils and lymphocytes to improve the QOL of patients.