Background/Purpose: The implementation of patient reported outcome measures (PROMs) is increasingly recognized as a critical aspect of clinical practice.  The use of gastrointestinal (GI) PROMs is particularly important in systemic sclerosis (SSc), especially for the identification of small intestinal bacterial overgrowth (SIBO), where hydrogen breath testing for definitive diagnosis is difficult to perform.  In this report, we examine the clinical correlates of two validated GI PROM scores in SSc to inform the design of a pragmatic trial in SSc SIBO.

Methods: Patients seen at a single center SSc Clinic, who met the 2013 ACR/EULAR Criteria and were enrolled in the INSYNC registry received an electronic link to a personal health assessment questionnaire that included the Scleroderma Clinical Trials Consortium University of California Los Angeles Gastrointestinal Tract (GIT 2.0) and gastrointestinal global symptom score (GSS), which have previously been validated in the SSc population. The GIT 2.0 (34 questions) provides a total score of GIT severity, and is calculated by an average of all scales (questions 1-8 reflux, 9-12 distention/boating, 13 soilage, 14-15 diarrhea, 16-21 social function, 22-30 emotional well-being, 31-34 constipation), except constipation.  The scores range from mild (0-0.49) to severe-to very-severe (1.01-3). The GSS assesses nausea, vomiting, abdominal pain/discomfort, bloating, diarrhea, constipation, abdominal tenderness, dysuria, tenesmus, fever and general illness/malaise, with each symptom scored from 0 (absent) to 3 (severe). It has previously been reported in the SSc population that a GSS ≥ 5 is predictive of SIBO. We compared the GIT 2.0 scores in those with GSS <5 and ≥ 5, using the t-test, with significance set at 5%.

Results:  From January to May 2018, 43 SSc patients completed both the SCTC GIT 2.0 and GSS (59 % completion rate).  These patients were 95% female, 67% limited cutaneous subtype, 73% scleroderma-specific autoantibodies (40.5% centromere, 13.5% SCL70, 18.9% RNApol3), with an average disease duration of 13.5 years. The subscales of GIT 2.0 according to GSS are shown in Table 1. As expected the potential SIBO patients with a GSS ≥ 5 had significantly more distention/bloating (p=0.001), but unexpectedly more constipation (p=0.04) on the GIT 2.0. 

Conclusion:  Gastrointestinal complaints are common in SSc and PROM questionnaires are an essential aspect of care, but the optimal number of questions and mode of questionnaire delivery are important as evidenced by our completion rate. If a GSS ≥ 5 represents SIBO, then this study suggests that subscales of the GIT 2.0 may be able to effectively capture this disease entity. The social functioning and emotional well-being domains of GIT 2.0 warrant further study in SIBO patients.

Table 1: Subscales of the GIT 2.0 according to GSS (with > 5 possibly identifying SIBO)