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.