Table 5. Multivariable logistic regression analysis to identify risk factors for frequent exacerbation.
Variables | RR | 95%CI | p-value |
Age, per increase of 1 year | 1.00 | 0.93–1.09 | 0.90 |
Smoking index, per increase of 1 pack-year | 0.98 | 0.96–1.00 | 0.10 |
Body mass index, per increase of 1 kg/m2 | 0.89 | 0.70–1.12 | 0.34 |
CRP, per increase of 1 µg/ml | 0.99 | 0.99–1.00 | 0.70 |
γ-globulin, per increase of 1 g/dL | 2.07 | 0.17–25.1 | 0.56 |
ICS, yes/no | 2.01 | 0.57–7.55 | 0.28 |
Tiotropium, yes/no | 1.53 | 0.41–5.80 | 0.52 |
LABA, yes/no | 1.31 | 0.33–5.20 | 0.69 |
%FEV1, per increase of 1% | 0.99 | 0.94–1.02 | 0.49 |
Exacerbations in previous year, yes/no | 4.43 | 1.20–19.6 | 0.025 |
Normal IgG antibody titer againstPorphyromonas gingivalis., yes/no | 5.27 | 1.30–25.7 | 0.019 |
Frequent exacerbation is defined as ≥2 exacerbations per year.
RR, relative risk; CI, confidence interval; CRP, C-reactive protein; ICS, inhaled corticosteroid; LABA, long-acting β2 agonist.