Analysis of longitudinal changes in dyspnea of patients with chronic obstructive pulmonary disease: an observational study

Table 3 Correlation coefficients between the changes in dyspnea and the changes in clinical variables

	OCD (/year)	mMRC (/year)	CRQ dyspnea (/year)	SGRQ activity (/year)	Borg score (/year)
Body mass index (kg/m²/year)	0.10	-0.16	0.28*	-0.19	0.14
Resting physiological measurements
FEV₁ (ml/year)	0.30*	-0.35*	0.36*	-0.47*	-0.08
FEV₁ (%predicted/year)	0.29*	-0.37*	0.37*	-0.49*	-0.10
FRC (%predicted/year)	0.08	-0.03	-0.18	-0.10	0.11
DL_CO (%predicted/year)	0.27*	-0.35*	0.32*	-0.27*	0.03
Peak exercise measurements
Peak V₂ (ml/min/kg/year)	0.25*	-0.35*	0.16	-0.21	0.07
Peak V (l/min/year)	0.27*	-0.30*	0.22*	-0.24*	0.08
Peak V (%predicted VC/year)	0.14	-0.26*	0.21	-0.30*	0.05
Psychological status measurements
HADS anxiety (/year)	-0.36*	0.36*	-0.33*	0.41*	-0.00
HADS depression (/year)	-0.45*	0.46*	-0.45*	0.43*	0.07

* p < 0.01. FEV₁ forced expiratory volume in one second; FRC functional residual capacity, DL_CO diffusing capacity for carbon monoxide, $\dot{V} O_{2}$ oxygen uptake, $\dot{V} E$ minute ventilation, $VT$ tidal volume, VC vital capacity, HADS Hospital Anxiety and Depression Scale, OCD Oxygen Cost Diagram, mMRC modified Medical Research Council dyspnea scale, CRQ Chronic Respiratory Disease Questionnaire, SGRQ St. George’s Respiratory Questionnaire.

ISSN: 1465-993X