Table 1:
Characteristics of isolated RA-associated bronchiectasis cases and controls
| Characteristic | Isolated RA- BR cases (n=57) |
RA controls without lung disease (n=360) |
p-value |
|---|---|---|---|
| Demographics | |||
| Female sex (n, %) | 49 (86.0%) | 275 (76.4%) | 0.11 |
| White (n, %) | 50 (87.7%) | 309 (85.8%) | 0.70 |
| Lifestyle factors | |||
| Smoking status (n, %) | |||
| Never | 24 (42.1%) | 165 (45.8%) | 0.25 |
| Past | 31 (54.4%) | 163 (45.3%) | |
| Current | 2 (3.5%) | 32 (8.9%) | |
| Pack-years (median and IQR) | 2.5 (0.0, 15.5) | 1.0 (0.0, 15.6) | 0.67 |
| BMI category at RA diagnosis (n, %) | 0.08 | ||
| Underweight | 3 (5.3%) | 13 (3.6%) | |
| Normal | 24 (42.1%) | 104 (28.9%) | |
| Overweight | 18 (31.6%) | 109 (30.3%) | |
| Obese | 12 (21.1%) | 134 (37.2%) | |
| BMI at RA diagnosis (kg/m2, median and IQR) | 25.3 (22.7, 28.5) | 27.6 (23.9, 32.7) | 0.003 |
| RA factors | |||
| Age at RA diagnosis (years, median and IQR) | 55.0 (44.2, 63.1) | 52.1 (40.2, 60.5) | 0.15 |
| RA duration at index date* (years median (IQR)) | 9.9 (2.8, 19.0) | 6.9 (1.6, 14.9) | 0.10 |
| Seropositive RA (n, %) | 48 (84.2%) | 201 (55.8%) | <0.0001 |
| RF+ (n, %) | 42 (73.7%) | 166 (46.1%) | <0.0001 |
| RF level (fold above ULN, median and IQR) | 5.4 (1.5, 22.8) | 1.0 (1.0, 6.2) | <0.0001 |
| Anti-CCP+ (n, %) | 33 (57.9%) | 147 (40.8%) | 0.0001 |
| Anti-CCP level (-fold above ULN, median and IQR) | 9.5 (0.9, 24.3) | 0.8 (0.3, 11.7) | 0.0009 |
| Ever DMARD use prior to index date * | |||
| csDMARD | 45 (79.0%) | 296 (82.2%) | 0.55 |
| Methotrexate | 40 (70.2%) | 236 (65.6%) | 0.49 |
| Hydroxychloroquine | 25 (43.9%) | 159 (44.2%) | 0.97 |
| Sulfasalazine | 8 (14.0%) | 58 (16.1%) | 0.69 |
| Leflunomide | 5 (8.8%) | 39 (10.8%) | 0.64 |
| bDMARD | 35 (61.4%) | 183 (50.8%) | 0.14 |
| TNF inhibitor | 32 (56.1%) | 157 (43.6%) | 0.08 |
| Abatacept | 2 (3.5%) | 54 (15.0%) | 0.007 |
| Rituximab | 5 (8.8%) | 30 (8.3%) | 0.91 |
| Tocilizumab | 3 (5.3%) | 22 (6.1%) | 0.24 |
| tsDMARD | 2 (3.5%) | 22 (6.11%) | 0.20 |
Anti-CCP = cyclic citrullinated peptide; BMI = body mass index; bDMARD = biologic disease modifying antirheumatic drug; csDMARD = conventional synthetic disease modifying antirheumatic drug; IQR = interquartile range; RA = rheumatoid arthritis; RA-BR = rheumatoid arthritis-associated bronchiectasis; RF = rheumatoid factor; TNF = tumor necrosis factor; tsDMARD = targeted synthetic disease modifying antirheumatic drug (e.g., Janus kinase inhibitors such as tofacitinib); ULN = upper limit of normal
*
Index date was date of RA-BR detection for cases and date of chest CT scan reviewed by thoracic radiologists for research purposes for controls