Multivariable Cox regression model of risk factors for developing arrhythmia overall in patients with systemic sclerosis (SSc) comprising sex (women as reference), index age (as a continuous variable) and baseline comorbidities, in addition to pulmonary arterial hypertension (PAH), interstitial lung disease (ILD) and SSc-related drugs as time-varying covariates
| Variable | SSc population (n=1393) | HR (95% CI) |
| Age (continuous) | – | 1.05 (1.03 to 1.07) |
| Sex (women as reference) | 1146 | 1.8 (1.2 to 2.6) |
| Diabetes | 85 | 0.9 (0.5 to 1.8) |
| Hypertension | 514 | 1.4 (1.0 to 2.1) |
| Heart failure | 60 | 1.3 (0.6 to 2.5) |
| Ischaemic heart disease | 91 | 0.9 (0.5 to 1.5) |
| Asthma/COPD | 330 | 0.9 (0.6 to 1.3) |
| Renal disease | 63 | 1.6 (0.8 to 3.0) |
| PAH | 151 | 2.8 (1.6 to 4.8) |
| ILD | 209 | 0.6 (0.3 to 1.1) |
| Methotrexate | 250 | 0.7 (0.4 to 1.3) |
| Mycophenolic acid | 301 | 1.2 (0.7 to 1.9) |
| Hydroxychloroquine | 134 | 1.0 (0.5 to 2.1) |
| PDE5 inhibitors | 264 | 1.2 (0.7 to 2.0) |
| CCB | 950 | 0.9 (0.6 to 1.3) |
Bold font indicates statistically significant values.
CCB, calcium channel blockers; COPD, chronic obstructive pulmonary disease; PDE5, inhibitors phosphodiesterase-5 inhibitors.