Researchers from the University of Cologne in Germany showed that Systemic sclerosis-overlap Syndrome should be regarded as different separate subset in Systemic sclerosis (SSc) patients. The study entitled “Disease progression in systemic sclerosis-overlap syndrome is significantly different from limited and diffuse cutaneous systemic sclerosis” appeared on Annals of the Rheumatic Diseases (ARD), March 25, 2015.
The study, based on data of 3,240 patients registered in the database of the German Network for Systemic Scleroderma (or SSc) followed between 2003 and 2013 demonstrates that patients classified as overlap syndromes show a disease course significantly different from patients with limited SSc (lcSSc) or diffuse cutaneous SSc (dcSSc).
SSc is a chronic systemic autoimmune disorder causing accumulation of collagen that leads to fibrosis of the skin and many internal organs. Limited SSc mostly affects the skin whereas dcSSc affects the skin as well as the heart, lungs, gastrointestinal tract, and kidneys. “Overlap syndrome” is a concept used whenever symptoms from two or more diseases are identified in the same patient. A considerable number of SSc patients showing symptoms associated with at least to other connective tissue diseases (CTD) are diagnosed with SSc-overlap syndrome.
In this study, patients with SSc-overlap syndrome were characterized in comparison to SSc and lcSSc to improve diagnosis criteria and to discuss whether these characterize a different subset. The Cologne researchers found that SSc-overlap patients had a mean age of 48 ±1.2 years and 68% of them had a different pattern of antibodies against nuclear cell proteins (autoantibodies). These patients also developed musculoskeletal involvement, including muscle weakness and synovitis, more frequently (62.5%) and significantly earlier than patients diagnosed as lcSSc (32.2%) or dcSSc (43.3%). The involvement of other organs such as lung and heart also differs from other Ssc subsets. The onset of lung fibrosis and heart involvement in patients with SSc-overlap syndromes had an intermediate rate of disease progression, between lcSSc and dcSSc.
“In summary, we could demonstrate that patients with overlap syndromes differ from lcSSc and dcSSc regarding lung fibrosis and heart involvement, and that musculoskeletal involvement is clearly the most frequent organ manifestation in overlap patients,” concluded the authors of this study.