Background Reliable data regarding the prevalence of specific medical comorbidities among patients with PrimarySjögren's Syndrome (pSS) remain sparse and there are not comparative studies among patients with pSS and patients with Systemic Lupus Erythematosus (SLE).
Objectives To compare the prevalence of the main comorbidities of two large cohorts of patients with pSS and SLE, with focus in cardiovascular (CV) diseases.
Methods Cross-sectional multicenter study comparing cumulative prevalence of the most relevant comorbidities, with identical definition in both cohorts. Patients on follow-up from SJOGRENSER (Spanish Register of pSS) and RELESSER (Spanish Register of SLE), fulfilling AECG-2002 and ACR-97 classification criteria, were included. Binomial logistic regression analysis was carried out to explore potential differences, adjusting for age, sex and disease duration with further specific adjustments for each variable, including CV risk factors and treatments, when it was considered convenient.
Results 437 pSS (95.2% female) and 2,960 SLE (89.5% female) patients were included. Mean age: 58.6 (p55-p75: 50.0–69.9) and 46.4years (22.4–41.6) respectively (p<0.001). Disease duration 10,4 (6.0–16.7) and 13.3 years (8.80–20.04) respectively (p<0.001).
Patients with pSS were hospitalized by the disease activity lesser than SLE: 17% vs 53%, p<0.001; OR 0.18 (95%CI:0.14–0.24). Moreover, the use of GC or IS were less prevalent in pSS [GC: 49.4% in pSS vs 88.2% in SLE; OR:0.13 (0.10–0.16); azathioprine: 10.1% vs 32.4%; OR: 0.24 (0.17–0.33); mycophenolate: 3.9% vs 16.2%; OR:0.21 (0.13–0.35); cyclophosphamide: 3.0% vs 22.6%; OR: 0.11 (0.06–0.18)].
The following comorbidities were less prevalent in pSS: Smoking [25.3% vs 48.2%, p<0.001, OR:0.50 (95%CI:0.40–0.64)], hypertension [25.3%vs 27.3%, p<0.001, OR: 0.44 (0.33–0.58)] and life-threatening CV events [(6.8% vs 8.5%, OR:0.53 (0.32–0.87)]. Severe infections were also more frequent in SLE [17.7% vs 10.1%, p<0.001, OR: 0.52 (0.37–0.72)], but this difference lost statistical significance when adjusted for glucocorticoid (GC) and immunosupressors (IS) use. Conversely, fibromyalgia and lymphoma were more frequent in pSS [14.6 vs 5.2%, p<0.001, OR: 2.70 (1.93–3.80)] and [1.6 vs 0.3%, p=0.002; OR: 5.71 (1.83–17.79)] respectively.
Conclusions pSS patients have consistently less serious comorbidity burden compared with SLE patients, namely less CV diseases and less infections. In contrast, the risk of lymphoma exceeds that seen in SLE patients. The higher prevalence of CV events in SLE does not seem to be explained only by traditional CV risk factors, suggesting that SLE derived factors could be involved.
Acknowledgement Systemic Autoimmune Diseases Group of Spanish Society of Rheumatology (EAS-SER) and SER Research Unit
Disclosure of Interest None declared