Table 1. Baseline characteristics (N = 550).
| RA with NTM* (n = 50) |
Control subjects (n = 500) |
p value | |||
|---|---|---|---|---|---|
| n | % | n | % | ||
| Age at entry, years | |||||
| Mean ± SD | 57.6 ± 15.4 | 57.4 ± 15.3 | 0.96 | ||
| Age | 1 | ||||
| 18–44 | 9 | (18.0%) | 90 | (18.0%) | |
| 45–64 | 18 | (36.0%) | 180 | (36.0%) | |
| ≥65 | 23 | (46.0%) | 230 | (46.0%) | |
| Gender | 1 | ||||
| Female | 27 | (54.0%) | 270 | (54.0%) | |
| Male | 23 | (46.0%) | 230 | (46.0%) | |
| RA disease duration (years) | 10.4 ± 3.7 | 10.3 ± 3.7 | 0.86 | ||
| RA to NTM period (years) | 6.7 ± 4.3 | N/A# | |||
| BMI†, kg/m2 | 22.3 ± 3.6 | 23.9 ± 3.7 | 0.005 | ||
| Smoking history | 12 | (24.0%) | 120 | (24.0%) | 0.862 |
| TB history | 17 | (34.0%) | 42 | (8.4%) | <0.001 |
| Comorbidities | |||||
| Hypertension | 26 | (52.0%) | 124 | (24.8%) | <0.001 |
| Diabetes mellitus | 15 | (30.0%) | 56 | (11.2%) | <0.001 |
| Chronic kidney disease | 12 | (24.0%) | 53 | (10.6%) | 0.01 |
| Interstitial lung disease | 11 | (22.0%) | 19 | (3.8%) | <0.001 |
| COPD | 9 | (18.0%) | 13 | (2.6%) | <0.001 |
| Anti-rheumatic medication | |||||
| Anti-TNF biologics‡ | 15 | (30.0%) | 56 | (11.2%) | <0.001 |
| Non-anti-TNF biologics§ | 6 | (12.0%) | 30 | (6.0%) | 0.13 |
| Oral corticosteroids | 40 | (80.0%) | 268 | (53.6%) | <0.001 |
| csDMARDs | |||||
| Hydroxychloroquine | 23 | (46.0%) | 201 | (40.2%) | 0.52 |
| Sulfasalazine | 26 | (52.0%) | 186 | (37.2%) | 0.06 |
| Methotrexate | 21 | (42.0%) | 178 | (35.6%) | 0.46 |
| Outcomes¶ | |||||
| Hospitalization | 36 | (72.0%) | 157 | (31.4%) | <0.001 |
| Died | 8 | (16.0)% | 11 | (2.2%) | <0.001 |
*NTM, nontuberculous mycobacteria.
†BMI, body mass index; TB, tuberculosis; COPD, chronic obstructive pulmonary disease.
‡Anti-TNF biologics, anti-tumor necrosis factor biologics, including adalimumab and etanercept.
§Non anti-TNF biologics, including rituximab, tocilizumab and abatacept.
¶csDMARDs, conventional synthetic disease-modifying anti-rheumatic drugs.
#N/A denotes ‘not measured’.