. 2009 Oct 16;137(4):823–830. doi: 10.1378/chest.09-0764

Table 3.

—Bivariate Correlations of Health-Related Quality-of-Life, Psychologic, and COPD Severity Factors With the COPD Helplessness Index

Factors Associated with CHI	Mean ± SD	Correlation with CHI r	P Value
HRQL and psychologic factors
Overall physical HRQL (SF-12 PCS)^a	38.3 ± 11.2	−0.42	< .001
Respiratory-specific HRQL (AQ20-R)^b	8.9 ± 4.6	0.54	< .001
Depression scale (GDS)^b	4.0 ± 3.6	0.55	< .001
Anxiety scale (HADS–anxiety subscale)^b	4.4 ± 4.0	0.41	< .001
COPD severity
BODE Index (total)^b	2.9 ± 2.4	0.34	< .001
Selected BODE components
FEV₁ % predicted^a	62.4 ± 23.3	−0.11	< .001
MMRC dyspnea scale^b	2.4 ± 1.7	0.45	< .001
6-min walk test, m^a	403 ± 120	−0.25	< .001

AQ20-R = Airways Questionnaire 20, Revised; CHI = COPD Helplessness Index; GDS = Geriatric Depression Scale; HADS = Hospital Anxiety Depression Scale; HRQL = health-related quality of life; MMRC = Modified Medical Research Council; PCS = Physical Component Summary; SF-12 = Short Form-12. See Table 1 for expansion of other abbreviations.

Higher SF-12 PCS scores, higher FEV₁% predicted, and greater distance walked on the 6-min walk test reflect better health status.

Higher AQ20-R, GDS, HADS, MMRC Dyspnea Scale, and BODE Index scores reflect worse health status. (FEV₁ and the 6-min walk test are reverse scored for the summary BODE Index.)