Table 1.
Demographical and social characteristics of hospitalised primary Sjögren’s syndrome patients and controls and adjustment covariates.
| Primary Sjögren’s Syndrome Patients (n = 25,661) | Matched Controls (n = 252,543) |
||||
|---|---|---|---|---|---|
| Number of Patients | % of pSS Patients |
Number of Matched Patients |
% of Matched Patients | Comparison (p Value) | |
| Sex (female) (n, %) | 22,489 | 87.66% | 224,887 | 87.65% | 0.995 |
| Low socio-economic status (n, %) | 1224 | 4.77% | 8482 | 3.31% | <0.001 |
| Age (mean, SD) (years) | 60.2 | ±16.3 | 60.0 | ±16.3 | 0.075 * |
| Number of hospitalisations before index date (mean, SD) |
3.7 | ±9.0 | 0.21 | ±1.1 | <0.001 * |
| Annual rate of hospitalisations before index date (n, %) | |||||
| ≤0.25 per year | 10,245 | 39.93% | 244107 | 95.15% | <0.001 |
| Between 0.25 and 0.5 per year | 5959 | 23.23% | 8679 | 3.38% | . |
| Between 0.5 and 1 per year | 5430 | 21.16% | 2807 | 1.09% | . |
| Between 1 and 5 per year | 3704 | 14.44% | 908 | 0.35% | . |
| More than 5 per year | 318 | 1.24% | 59 | 0.02% | . |
| Deaths (incidence a, 95%CI) | 14.4 | (13.7–15.2) | 10.5 | (10.3–10.7) | <0.001 |
| Follow-up time after index date (median, (IQR), years) |
3.96 | (1.96–5.96) | 3.96 | (1.96–6.04) | 0.003 * |
| Past medical history mentioned in previous hospitalisations (used as adjustment covariates) | |||||
| Cardiovascular risk factors or associated reported during a hospitalisation | |||||
| Hypertension | 274 | 1.07% | 876 | 0.35% | <0.001 |
| Diabetes | 656 | 2.56% | 2818 | 1.12% | <0.001 |
| Obesity | 294 | 1.15% | 1393 | 0.55% | <0.001 |
| Sleep apnoea syndrome | 560 | 2.18% | 1461 | 0.58% | <0.001 |
| All cardiovascular diseases b | 1361 | 5.30% | 8281 | 3.28% | <0.001 |
| Chronic kidney disease | 251 | 0.98% | 450 | 0.18% | <0.001 |
| Dialysis | 83 | 0.32% | 214 | 0.08% | <0.001 |
| Cardiovascular events | |||||
| Ischemic heart disease | 871 | 3.39% | 5174 | 2.05% | <0.001 |
| Stroke | 356 | 1.39% | 2304 | 0.91% | <0.001 |
| All venous thromboembolic events c | 155 | 0.60% | 515 | 0.20% | <0.001 |
| Pulmonary hypertension | 127 | 0.49% | 65 | 0.03% | <0.001 |
| Other covariates | |||||
| Interstitial pneumonitis or lung fibrosis | 695 | 2,71% | 154 | 0.06% | <0.001 |
| Chronic obstructive pulmonary disease | 442 | 1.72% | 1202 | 0.48% | <0.001 |
| Neuro-psychiatric disorders d | 667 | 2.60% | 2529 | 0.99% | <0.001 |
pSS, primary Sjögren’s syndrome; n, number; SD, standard deviation; CI, confidence interval; all comparisons were performed with Chi2 test except those denoted with an asterisk (*), performed with Wilcoxon–Mann–Whitney rank sum test; a number of incident deaths per 1000 person-years; b cardiovascular diseases (ischemic heart disease, stroke, aortic dissection, aortic and peripheral arterial diseases, and hypertensive chronic kidney disease); c vein thromboses and pulmonary embolism; d anxiety, depression, dementia.