Kidney injury in systemic lupus erythematosus: lack of correlation between clinical and histological data.

BACKGROUND: The existence and type of renal involvement influences the prognosis of systemic lupus erythematosus and this information may be critical when it comes to taking appropriate therapeutic decisions.

OBJECTIVE: To evaluate statistical correlations between clinical and histological data in patients with biopsied lupus nephropathy.

METHODS: Review of clinical information in adult kidney biopsy requests reported between 2002 and 2014 with a definitive clinical and histopathological diagnosis of renal involvement in systemic lupus erythematosus.

RESULTS: 134 cases (86% women), aged 15-59 years. Indication for renal biopsy: asymptomatic urinary abnormalities (30%), nephrotic proteinuria without hypoalbuminaemia (9%), nephrotic syndrome (19%), renal failure (40%) and two cases without clinical renal manifestations. The most common lesions were purely proliferative (68%). In patients with asymptomatic urinary abnormalities, 35% were class IV, 30% class III, 23% mixed, 10% class V and 2% class II. In subjects with nephrotic proteinuria, 75% were class IV, 17% mixed and 8% class III. In nephrotic syndrome patients, 46% were class IV, 27% class V, 19% mixed and 8% class III. In renal failure subjects, 67% were class IV, 22% mixed, 7% class III and 4% class V. These proportions were not statistically different. Although class IV showed the worst renal function, almost half (44%) of those without renal failure belonged to this class.

CONCLUSION: We could not demonstrate a consistent clinical-pathological relationship that predicts patterns or severity of histological findings based on the clinical profile in patients with systemic lupus erythematosus and renal manifestations. These results highlight the importance of biopsy as a key diagnostic tool in this disease.