Table 2.
Hazard ratios for incident COPD after blood draw date, comparing women with RA to their matched controls in the Nurses’ Health Studies (n=1,125).
| Incident COPD cases/person-years |
HR (95%CI) controlling for matching factors* |
Multivariable** HR (95%CI) |
|
|---|---|---|---|
| Pre-RA ACPA+ (n=59) | 13/1,030 | 3.02 (1.42, 6.43) | 3.04 (1.33, 7.00) |
| Matched controls (n=176) | 14/3,375 | 1.00 (Ref) | 1.00 (Ref) |
| Pre-RA ACPA− (n=224) | 23/4,117 | 1.27 (0.78, 2.06) | 1.07 (0.65, 1.75) |
| Matched controls (n=666) | 57/12,967 | 1.00 (Ref) | 1.00 (Ref) |
| All pre-RA (n=283) | 36/5,147 | 1.61 (1.08, 2.40) | 1.39 (0.92, 2.09) |
| Matched controls (n=842) | 71/16,342 | 1.00 (Ref) | 1.00 (Ref) |
P for pre-RA/control status-ACPA status interaction in unadjusted analysis: 0.71
P for pre-RA/control status-ACPA status interaction in adjusted analysis: 0.27
Each woman with RA was matched to 3 controls by age, time from blood draw to index date, cohort, calendar year, fasting status/time of day at blood draw, menopausal status, and postmenopausal hormone use.
Additionally adjusted for smoking (continuous pack-years), body mass index (continuous, kg/m2), median household income (quartile), and asthma (yes/no).
ACPA, anti-citrullinated protein antibodies; CI, confidence interval; COPD, chronic obstructive pulmonary disease; HR, hazard ratio; RA, rheumatoid arthritis.