Table 1.
Baseline characteristics of pre-existing RA cases (n=87) and matched non-RA comparators (n=203) at index date of immune checkpoint inhibitor initiation.
| Pre-existing RA cases (n=87) |
Matched non-RA comparators (n=203) |
p-value | |
|---|---|---|---|
| Demographics | |||
| Mean age, years (SD) | 69.9 (10.6) | 69.4 (10.4) | 0.76* |
| Sex, n (%) | |||
| Female | 52 (60%) | 126 (62%) | 0.71* |
| Male | 35 (40%) | 77 (38%) | |
| Race, n (%)** | |||
| White | 81 (93%) | 187 (92%) | 0.96 |
| Black | 3 (3%) | 7 (3%) | |
| Asian | 1 (1%) | 2 (1%) | |
| Median calendar year (IQR) | 2018 (2017, 2019) | 2018 (2017, 2019) | 0.42* |
| Lifestyle | |||
| Smoking status, n (%) | |||
| Never | 24 (29%) | 51 (25%) | 0.56 |
| Past | 57 (66%) | 130 (64%) | |
| Current | 6 (7%) | 22 (11%) | |
| Median pack-years (IQR) | 20 (0, 40) | 20 (0, 40) | 0.90 |
| Median body mass index, kg/m2 (IQR) | 25.8 (22.0, 29.4) | 26.0 (23.3, 31.0) | 0.065 |
| Comorbidities | |||
| Median CCI (IQR) | 8 (6, 9) | 8 (3, 10) | 0.44 |
| Cancer characteristics | |||
| Target of ICI, n (%) | 0.94* | ||
| PD-1 | 80 (92%) | 188 (93%) | |
| PD-L1 | 4 (5%) | 9 (4%) | |
| CTLA-4 | 1 (1%) | 1 (1%) | |
| Combination | 2 (2%) | 5 (3%) | |
| Type of cancer, n (%) | |||
| Lung | 43 (49%) | 114 (56%) | 0.29* |
| Non-small cell | 41 (47.1%) | 112 (55%) | 0.21* |
| Small cell | 2 (2%) | 2 (1%) | 0.27* |
| Melanoma | 21 (24%) | 50 (25%) | 0.93* |
| Genitourinary tract | 6 (7%) | 12 (6%) | 0.75* |
| Gastrointestinal tract | 3 (4%) | 6 (3%) | 0.27* |
| Head and neck | 4 (5%) | 7 (4%) | 0.22* |
| Hematologic | 3 (4%) | 3 (2%) | 0.19* |
| Brain | 2 (2%) | 5 (3%) | 0.32* |
| Other*** | 5 (6%) | 6 (%) | 0.25* |
| Median cancer duration, years (IQR) | 0.9 (0.1, 2.4) | 0.6 (0.1, 1.9) | 0.66 |
| Previous chemotherapy, n (%) | 53 (61%) | 91 (45%) | 0.012 |
| Previous hormonal therapy, n (%) | 1 (1%) | 4 (2%) | 0.36 |
| Previous radiation, n (%) | 48 (55%) | 71 (35%) | 0.0014 |
| Previous stem cell transplant, n (%) | 2 (2%) | 2 (1%) | 0.267 |
| Previous CAR-T therapy, n (%) | 0 (0%) | 1 (1%) | 0.70 |
| Any previous chemotherapy, hormonal therapy, radiation, stem cell transplant, or CAR-T, n (%) | 53 (61%) | 94 (46%) | 0.023 |
| RA characteristics | |||
| Median RA duration, years (IQR) | 9.4 (4.6, 16.5) | ||
| Seropositive, n (%) | 49/71 (69%) | ||
| Anti-CCP+, n (%) | 35/57 (61%) | ||
| RF+ | 37/58 (64%) | ||
| Most recent disease activity, n (%) | |||
| Remission | 29/68 (43%) | ||
| Low | 25/68 (37%) | ||
| Moderate | 11/68 (16%) | ||
| High | 3/68 (4%) | ||
| Glucocorticoid (n, %) | 57 (66%) | ||
| Median prednisone dose, mg/day (IQR) | 10 (5, 26) | ||
| Any DMARD (n, %) | 40 (46%) | ||
| Any csDMARD (n, %) | 31 (36%) | ||
| Methotrexate (n, %) | 19 (22%) | ||
| Hydroxychloroquine (n, %) | 11 (13%) | ||
| Any bDMARD or tsDMARD (n, %) | 22 (25%) | ||
| TNFi (n, %) | 10 (12%) | ||
| Bone erosions or deformities, n (%) | 27 (31%) | ||
| Interstitial lung disease, n (%) | 13 (15%) | ||
| Rheumatoid vasculitis, n (%) | 1 (1%) | ||
| Sjogren’s syndrome, n (%) | 0 (0.0%) | ||
| Felty’s syndrome, n (%) | 0 (0.0%) |
Some percentages may not total 100% due to rounding. Missing data: race, 2 cases and 7 comparators; BMI, 9 cases and 20 comparators. RA characteristics- serostatus 16; anti-CCP 30; RF status 29; disease activity 19. All other variables had complete data.
Age, sex, calendar year, ICI target, and cancer type/stage were matching factors.
No patients reported other races or Hispanic/Latinx ethnicity.
Other cancers included neuroendocrine (2 cases and 2 comparators), Merkel cell carcinoma (2 cases and 3 comparators), and mesothelioma (1 case and 1 comparator).
CAR-T, chimeric antigen receptor T cells; CCI, Charlson Comorbidity Index; CTLA-4, cytotoxic T-lymphocyte-associated protein 4; ICI, immune checkpoint inhibitor; IQR, interquartile range; PD-1, programmed cell death protein 1; PD-L1, programmed death-ligand 1; RA, rheumatoid arthritis; SD, standard deviation.