Table 5.

Logistic regression analysis of exacerbation rate

Independent variable	Beta value	t-Value	P-value
Mild COPD (constant)
COPD very severe	0.230	4.622	0.000
COPD severe	0.196	3.259	0.001
COPD moderate	0.118	1.971	0.049
Undertreated	−0.179	−3.759	0.000
Overtreated	0.039	0.871	0.384
Incorrect treatment	−0.055	−1.231	0.219
Smoker	0.042	1.198	0.231
Age	−0.047	−1.348	0.178

Notes: The dependent variable is exacerbation rate per year. Independent variables are as listed. The beta coefficient indicates the strength and direction of the relationship of the independent variable to exacerbation rate holding the other independent variables constant. The t- and P-values refer to the significance of the beta coefficient.

Abbreviation: COPD, chronic obstructive pulmonary disease.