Risk factors for systemic lupus erythematosus flares in patients with end-stage renal disease: a case-control study

The aim of this study was to recognize risk factors for extrarenal SLE flares in patients with end-stage renal disease (ESRD) receiving renal replacement therapy (RRT).

We performed a retrospective, case-control study in a tertiary care hospital in Mexico City from 1993 to 2014. Cases were lupus patients who had any extrarenal flare after RRT. Controls were SLE patients with ESRD but without flares. We recorded demographic features and clinical and immunological parameters. Differences between groups were analysed by Student's t-test. Association was assessed by the odds ratio (OR) and 95% CI. Multivariate analysis was performed by binary logistic regression.

Eighty-eight patients were included: 38 cases (50 flares) and 50 controls. The proportion of men was higher in cases (24 vs 8%, P = 0.029). The most common flares were haematologic (42%), mucocutaneous (38%) and articular (30%). Independent risk factors for flares included age at RRT start [OR 0.92 (95% CI 0.88, 0.96), P < 0.001], history of haematologic activity [OR 3.79 (95% CI 1.05, 13.7), P = 0.04], anti-cardiolipin IgM [OR 4.39 (95% CI 1.32, 14.6), P = 0.02] and low C4 levels [OR 9.7 (95% CI 2.49, 39.12), P = 0.001].

SLE patients continue to be at risk for extrarenal activity after RRT. The most common flare was haematologic, which correlated with the history of haematologic activity and anti-cardiolipin positivity as independent risk factors. Lower C4 levels and younger age at the beginning of RRT were also associated. Patients with these characteristics should have a closer follow-up in order to detect and treat SLE flares in a timely manner.