Predictive factors for the development of lupus nephritis after diagnosis of systemic lupus erythematosus

To determine predictive factors for the development of lupus nephritis (LN) at the time of diagnosis of systemic lupus erythematosus (SLE).

A case-control study was carried out in a single center, 595 patients with a diagnosis of SLE without LN participated by clinical or laboratory parameters at diagnosis, they were followed for a mean of 6.8 (+4.5) years, conforming to the data of their files two groups: with NL (cases) and without NL (controls) at the end of the follow-up. Sociodemographic, clinical, serological, immunological variables and the albumin - globulin ratio (AGR), calculated as albumin/total protein-albumin at diagnosis, were compared between both groups. A univariate and multivariate analysis was carried out.

124 (20.8%) patients had LN during follow-up and 471 (79.2%) did not develop LN. Univariate analysis: variables significantly associated with the development of LN: smoking, oral ulcers, serositis, more than four classification criteria, abrupt onset of SLE, higher SLEDAI value, low AGR, low C3 levels, high anti-titers. -Double stranded DNA (anti-dc DNA), anti-nucleosomes and positivity of immunofluorescence in skin. Multivariate analysis: predictors of developing LN: elevated serum levels of anti-dc DNA (odds ratio (OR): 15.82; confidence interval (CI): 1.08-1.22, P < .0001), decrease in the C3 fraction (OR: 36.50; CI: 13.52-81.91, P < .0001) and the RAG < 1 (OR: 47.58; CI: 11.85-79.17, P < .0001).

The AGR below one was the greatest predictor of the appearance of LN, together with the low levels of C3 and high levels of anti-dc DNA antibodies, they may contribute to identifying patients with a higher risk of presenting LN.