Background/Purpose: Systemic Sclerosis (SSc) is a progressive systemic disease that can lead to variable degrees of morbidity and disability. Hand dysfunction in SSc patients [1] can result from pain, swelling and loss of mobility [1][2], affecting activities of daily living (ADLs) and work [3][4]. We aim to identify important clinical predictors of hand dysfunction in SSc.

Methods: We evaluated 192 outpatients who met criteria for SSc [5] and were seen between 2010 and 2015. We collected pertinent SSc clinical information, including laboratory and hand x-ray assessments obtained within 5 years of this analysis. Hand dysfunction was defined as the inability to make a fist due to inability to approximate the fingers onto the palm of the hand. This was corroborated by patientÕs history of difficulty with ADL tasks. We estimated unconditional logistic regression models adjusted for SSc type, current modified Rodnan skin score (mRSS), and overlap with rheumatoid arthritis (RA).

Results: Hand dysfunction occurred in 34% of patients (n=65). Patients with diffuse cutaneous SSc (dcSSc), high mRSS and overlap with RA had significantly more hand dysfunction. In multivariable models, after adjusting for these 3 variables, the following remained strongly associated with hand dysfunction: RNA polymerase III positivity (OR 3.3, CI 1.1-9.6), prior digital tip ulcers (DTUs)(OR 2.6, CI 1.3-5.4), current DTUs (OR 3.2, CI 1.4-7), prior tendon friction rubs (TFRs)(OR 5.0, CI 1.96-13), current TFRs (OR 3.5, CI 1.1-11), prior synovitis (OR 4.7, CI 1.9-26), osteoarthritis (OR 3.8, CI 1.6-8.9) and acro-osteolysis (OR 2.9, CI 1.3-6.6).

Conclusion: Hand dysfunction occurred in a third of our SSc population, and was more common in patients with dcSSc. Digital ischemia and inflammatory features (TFRs, synovitis) were strongly associated with hand dysfunction, which was independent of SSc type, degree of skin thickening, and overlap with RA. Prospective studies are needed to confirm if more aggressive treatment of digital ischemia and musculoskeletal inflammation in SSc patients would lead to less hand contractures and dysfunction. References:

1.     Erre et al. Joint Bone Spine 2008; 75:426

2.     Fontaine et al. Chirurgie de la main 2014; 33:155

3.     Sandqvist et al. Rheumatol. 2010; 49:1739

4.     Maddali-Bongi et al. Clin Exp Rheumatol. 2014; 32:S15

5.     Hoogen et al. Ann Rheum Dis. 2013; 72:1747 & Arthritis Rheum.  2013; 65: 2737  

*Adjusted for SSc type, overlap with RA, and mRSS    **Documented on physical exam    ***Documented by hand x-rays    ****Documented by high resolution chest CT            SSc: systemic sclerosis; DTU: digital tip ulcer; RA: rheumatoid arthritis; TFR: tendon friction rub; Anti-topo l: anti-topoisomerase I or Scl70; RNA pol III: anti-RNA polymerase III antibody; ACA: anti-centromere antibody; OA: osteoarthritis; ILD: interstitial lung disease; FVC: forced vital capacity; DLCO: diffuse capacity of the lung for carbon monoxide; mRSS: modified Rodnan skin score