Critical peripheral ischemia: Higher prevalence in Indian systemic lupus erythematosus inception cohort for research (INSPIRE).

INTRODUCTION: There is limited literature on digital ischemia in systemic Lupus erythematosus (SLE). We report the prevalence, associations and outcome of digital infarcts and gangrene from the Indian SLE inception cohort (INSPIRE). METHODS: From the web-based database of INSPIRE, we extracted information for patients with 'Digital Infarct' and 'Digital gangrene' at enrolment into cohort, together considered as critical peripheral ischemia (CPI); all others were controls. We describe the associations of CPI with SLE clinical phenotype, autoantibodies, and disease activity at enrolment. We also report short term outcomes viz. Digital tissue loss and early mortality up to 6 months and recurrence of digital ischemic events in cases till date. RESULTS: Of 2503 SLE patients enrolled into the INSPIRE cohort, we identified 75 (2.9%) patients with CPI, 72 (96%) women and 6 (8%) children. Of them, 55 (73.3%) had digital gangrene and 21 (28%) patients had digital infarcts. Majority of digital gangrene resulted in amputation distal to terminal phalanx (63.6%). Multivariable analysis showed that pulmonary hypertension AOR [6.34 (1.99, 20.2)], coexistent thrombosis AOR [27.8 (15.7, 48.7)], triple antiphospholipid antibody positivity AOR [5.36 (1.67, 16.9)] and the presence of anti-Scl-70-antibody AOR [5.59 (1.86, 16.7)] were more likely while patients with class 3 or 4 lupus nephritis AOR [0.37 (0.15, 0.95)] and anti-nucleosome antibodies AOR [0.47 (0.23, 0.99)] were less likely to be associated with CPI. SLEDAI and short-term mortality were similar between cases and controls. CONCLUSIONS: CPI occurred in a higher proportion (2.9%) of SLE patients in the INSPIRE cohort as compared to earlier reports. Both prothrombotic state and vasculopathy contribute to its occurrence.

Exploratory clinical subgroup clustering in systemic sclerosis: Results from the Indian Progressive Systemic Sclerosis Registry.

Objective: To conduct an exploratory cluster analysis of systemic sclerosis patients from the baseline data of the Indian systemic sclerosis registry. Methods: Patients satisfying American College of Rheumatology-European League Against Rheumatism classification criteria for systemic sclerosis were included. The clusters formed using clinical and immunological parameters were compared. Results: Of the 564 systemic sclerosis registry participants, 404 patients were included. We derived four clusters of which three were anti-topoisomerase I predominant and one was anti-centromere antibody 2 dominant. Cluster 1 (n-82 (20.3%)) had diffuse cutaneous systemic sclerosis patients with the most severe skin disease, anti-topoisomerase I positivity, males, younger age of onset and high prevalence of musculoskeletal, vasculopathic and gastrointestinal features. Cluster 2 (n-141 (34.9%)) was also diffuse cutaneous systemic sclerosis and anti-topoisomerase I predominant but with less severe skin phenotype than cluster 1 and a lesser prevalence of musculoskeletal, vasculopathic and gastrointestinal features. Cluster 3 (n-119 (29.5%)) had limited cutaneous systemic sclerosis patients with anti-topoisomerase I positivity along with other antibodies. The proximal muscle weakness was higher and digital pitting scars were lower, while other organ involvement was similar between clusters 2 and 3. Cluster 4 (n-62 (15.30%)) was the least severe group with limited cutaneous systemic sclerosis and anti-centromere antibody predominance. Age of onset was higher with low musculoskeletal disease and a higher presence of upper gastrointestinal features. The prevalence of interstitial lung disease was similar in the three anti-topoisomerase I predominant clusters. Conclusion: With exploratory cluster analysis, we confirmed the possibility of subclassification of systemic sclerosis along a spectrum based on clinical and immunological characteristics. We also corroborated the presence of anti-topoisomerase I in limited cutaneous systemic sclerosis and the association of interstitial lung disease with anti-topoisomerase I.