Table 4.

Multivariate regression analysis of the effect of serum lymphocyte % on frequent exacerbation.

	Odds ratio (95% CI)	P value
Baseline lymphocyte, %
Lymphocyte, %	0.98 (0.95–1.00)	0.056
Lymphocyte groups
Normal lymphocytea	Reference
Low lymphocyteb	1.27 (0.71–2.29)	0.417
Clustered analysis
Lymphocyte, %	0.99 (0.97–1.01)	0.175
Lymphocyte groups
Normal lymphocytea	Reference
Low lymphocyteb	1.00 (0.63–1.59)	0.989

Adjusted for age, sex, body mass index, smoking status (current or former), and baseline forced expiratory volume in 1 s, % predicted. Frequent exacerbation was defined as having two or more exacerbations per year.

CI confidence interval.

^aNormal lymphocyte group was defined as those with serum lymphocyte percentage 20 to 51%.

^bLow lymphocyte group was defined as those with serum lymphocyte percentage < 20%.