Durometry in SSc: The hard facts. A systematic literature review and additional pilot study.

OBJECTIVES: To investigate the reliability of durometry in systemic sclerosis (SSc), by means of a systematic review and additional pilot study. METHODS: Literature was systematically reviewed according to the PRISMA guidelines to identify all original studies assessing the reliability of durometry in SSc. Additionally, in the pilot study, intra-rater reliability was evaluated in a first cohort of 74 SSc patients (61 female, 13 LSSc/53 LcSSc/8 DcSSc). In a second separate set of 30 SSc patients (21 female, 4 LSSc/20 LcSSc/6 DcSSc), intra- and inter-rater reliability were evaluated. RESULTS: Only two unique records identified through the systematic review were qualified to generate conclusions. Regarding intra-rater reliability, Kissin reported excellent intra-class correlation coefficient values (ICC, 0.86-0.94) for measurements at nine skin sites in two DcSSc patients. Merkel and Kissin described, both in five DcSSc patients, good to excellent inter-rater reliability (ICC, 0.82-0.96 and 0.61-0.85) for measurements at respectively, six and nine skin sites. In our pilot study, ICC for intra-rater reliability at 17 standardized skin sites were excellent in both cohorts, ranging 0.93-0.99 and 0.78-0.98, respectively. ICC for inter-rater reliability at 17 standardized skin sites were good to excellent 0.63-0.93, except for the feet (0.48 and 0.52). CONCLUSION: The preliminary findings in the literature are supported by our pilot study in which we have attested the reliability of durometry in SSc patients. However, prior to including durometry as an (additional) outcome measure in SSc clinical trials, its validation status in the assessment of skin fibrosis needs to be completely attested.

High frequency ultrasonography: reliable tool to measure skin fibrosis in SSC? A systematic literature review and additional pilot study.

OBJECTIVES: To investigate the reliability of high frequency ultrasound (HFUS) in measuring skin fibrosis in SSc. METHODS: First, a systematic review (according to PRISMA) was conducted to identify studies that documented HFUS' reliability in SSc as a primary outcome. Then, in an additional pilot study, the inter- and intra-rater reliability of two investigators performing HFUS for dermal thickness (DT) measurements in a standardized manner across all 17 areas of the modified Rodnan Skin Score was evaluated in a group of 59 SSc patients and descriptively in 44 healthy controls (HC). As an external validation, DT measurements by HFUS were performed in a separate group of 30 SSc patients by the same first and another third investigator. RESULTS: The systematic review retained few (4/1719 unique records) small-scale studies, with mixed study populations (combining SSc and HC). The reported data herein are suggestive of the inter-/intra-rater reliability of HFUS (intra-class correlation coefficient [ICCs] ranging 0.65-0.94/0.55-0.96, respectively). Additionally, in our pilot study, inter-/intra-rater reliability was good-to-excellent in both SSc groups and HC (ICCs ranging 0.70-0.97/0.70-0.98 and 0.65-0.95/0.63-0.96, respectively). CONCLUSION: The identified small-scale studies were not only combining data from SSc and HC, they were also heterogeneous in terms of technical aspects (probes and frequency), image acquisition methods ([number of] areas assessed) and definitions used for skin thickness, which prevents drawing unequivocal conclusions. Despite these limitations, our standardized pilot study corroborated the findings in literature, paving the way for the applicability of HFUS as a reliable (complementary) tool to quantify skin fibrosis in SSc.

Coexistence of systemic and localized scleroderma: a systematic literature review and observational cohort study.

OBJECTIVE: SSc and localized sclerosis (LoS) are considered clinically distinct entities. We describe herein the coexistence of SSc and LoS by both a systematic literature review and an observational cohort study of unselected SSc patients. METHODS: Original studies documenting the coexistence of SSc and LoS were identified in three electronic databases by means of a systematic literature search according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Additionally, the coexistence of SSc and LoS was studied in a prospective cohort of SSc patients visiting the Ghent University Scleroderma Unit for their yearly follow-up visit between January 2018 and January 2019. RESULTS: Five studies were finally included for quality appraisal and data extraction. The coexistence of SSc and LoS ranged between 2.4 and 7.4%. RP, scleroderma pattern on nailfold videocapillaroscopy (NVC) and the presence of SSc-specific antibodies were commonly observed in coexistent cases. Additionally, coexistence of SSc and LoS was found in 8/296 (2.7%) consecutive SSc patients of the Ghent University Scleroderma Unit. RP was present in 6/8 coexistent cases; a scleroderma pattern on NVC was observed in all coexistent cases, and SSc-specific antibodies (i.e. cenp-B) were found in 4/8 coexistent cases. CONCLUSION: This is the first systematic literature review with additional cohort evaluation investigating the coexistence of SSc and LoS. A relatively high overlap of SSc and LoS was revealed, which is peculiar because both are rare diseases.