Background/Purpose: The optimal management of Systemic Sclerosis (SSc) is a challenge due to the complexity of early diagnosis and identification of patients who are at risk of progressive disease. Furthermore, there is no consensus about minimal clinically relevant treatment effect outcome measurements [1]. Besides that, randomized clinical trials about medications that are disease modifying for SSc in terms of disease activity are scarce [2]. The aim of our study was to examine the minimally clinically important investigations for starting immunosuppression in patients with SSc.
Methods: For this study the baseline visits of SSc patients referred to an academically day patient clinic for a two-day health care program between 2009 and 2012 were recorded. This annual program compromised visits to health care professionals and laboratory investigation, HRCT-thorax, lung function, Cardiopulmonary Exercise Test (CPET), echocardiography, ECG, SSc Health Assessment Questionnaire (SHAQ) and Short Form-36 (SF-36). After 2 weeks a multidisciplinary consultation resulted in a change of treatment if appropriate. The change of treatment was divided in start with immunosuppression versus no start with immunosuppression for the analysis. Logistic regression analysis was used to determine the relationship between start and no start with immunosuppression as dependent variable and clinical parameters as independent variables.
Results: Two hundred twenty-seven patients participated in the day care program for at least one visit. Their mean age was 54 years, 82% of the patients were female and 75 patients had a diffuse cutaneous SSc (DcSSc). Fourteen patients had a previous autologous haemopoietic stem cell transplantation and were excluded for the logistic regression analysis. Forty-six patients started with immunosuppression after visiting the day patient clinic.
The univariate regression analysis showed that DcSSc, younger age, shorter disease duration, shorter duration of Raynaud Phenomenon and organ/skin involvement, contractures, dyspnea, crackles, not suffering from calcinosis, higher MRSS, anti-Scl70 positivity, anticentromere negativity, higher ESR, higher CRP, lower Vital Capacitiy, alveolitis on HRCT, pericardial fluid, and the CPET parameters lower wattage and lower VO2 max of predicted were significantly associated with the start of immunosuppression. Multivariate regression analysis showed that male gender, shorter disease duration, higher MRSS, anticentromere negativity, alveolitis and lower VO2 max of predicted were significantly associated with the start of immunosuppression.
Conclusion:  Autoantibodies, MRSS, HRCT-thorax and CPET are minimally clinical important investigations that are advocated in clinical evaluation.

References
1. Gazi H, Pope JE, Clements P et al. Outcome measurements in scleroderma: results from a Delphi exercise. J Rheumatol 2007:34;501-509.
2. Kowal-Bielecka O, Landewé R, Avouac J et al. EULAR recommendations for the treatment of systemic sclerosis: a report from the EULAR Scleroderma Trials and Research group (EUSTAR). Ann Rheum Dis 2009:68620-628.