Thrombotic microangiopathy in systemic lupus erythematosus: a cohort study in North Taiwan

Thrombotic microangiopathy (TMA) co-existing with SLE is rarely reported. This study aimed to investigate the triggering factors, clinical features and outcomes of SLE patients with TMA in Northern Taiwan.

Twenty-five TMA cases out of 2461 SLE patients admitted to Taipei Veterans General Hospital, between 2000 and 2010, were enrolled.

When TMA occurred, 16 (64.0%) patients had infection; 22 (88.0%) were in an active disease state with a SLEDAI score >10. Among the infection group, 13 (81.3%) had an increase in the SLEDAI score of ≥ 4. We found that older age (≥ 50 years), low platelets (≤ 20,000/nm(3)), presence of infection, acute renal failure (ARF) or four or more TMA features were independent risk factors for persistent haematological abnormalities (P < 0.05); older age (≥ 50 years) and a high reticulocyte index (>2%) were the risk factors for persistent renal function impairment (P < 0.05). The overall mortality rate was 52.0% (13 out of 25); older age (≥ 40 years), low complement value, presence of infection (P < 0.001), two or more infection sources, ARF and four or more TMA features were the statistically significant factors contributing to a higher mortality rate. Patients receiving plasma exchange seven times or more had a significantly higher rate of improvement in renal function and haematological abnormalities.

Our study showed that infection was one of the major triggers for the flare-up of SLE disease activity and occurrence of TMA in SLE. Infection is also a strong risk factor for outcome in SLE patients with TMA. Plasma exchange can be considered as an adjuvant treatment modality.