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Lupus nephritis (LN) is the most common severe organic condition in patients with systemic lupus erythematosus (SLE), with an incidence ranging from 20% to 60%. Renal biopsy (RB) is essential for its diagnosis (DX), classification, prognosis, and treatment.
The International Society of Nephrology/Renal Pathology Society classifies LN into 6 histopathological classes based on the degree of glomerular injury observed in RB. Although there is generally a correlation between the severity and class of LN and its analytical manifestations, there may also be some clinical-histological discrepancies. We aimed to study how often this occurs in our hospital in order to increase the chances of early DX, given the severity of this disease without timely treatment. Our main objective is to describe the correlation between clinical-analytical findings and the degree of histopathological lesion in patients with LN in a third-level public hospital over a 7-year period. Secondarily, we aim to describe the relationship between creatinine levels and the activity/chronicity score of these patients.
An analytical, observational, cross-sectional, and retrospective study was conducted. Thirty-three patients were analyzed, of which 26, aged 15 and above were included, evaluated and diagnosed with LN between January 2016 and December 2022, in the Centenario Provincial Hospital nephrology ward, Rosario, Santa Fe. Seven patients were excluded due to incomplete clinical records. The analyzed data are presented according to the variables studied in average and standard deviations for continuous variables or proportions for the frequency of ordinal variables.
The data analysis revealed that 46.2% of LN patients presented with asymptomatic urinary abnormalities (AUA), 42.3% with nephritic syndrome, and 11.5% with nephrotic syndrome (NS). The age of patients at SLE diagnosis was 25 ± 9 years, the age of LN appearance was 28 ± 9.2 years, and the time elapsed between both diagnoses was 3.2 ± 4.2 years. Of all LN patients, 69.2% were female. Among the performed RBs, 57.7% showed LN class IV (see graph 1). The clinical-analytical and histopathological correlation is observed in graphs 2, 3, and 4, highlighting that 82% of patients with nephritic syndrome and 66.7% of patients with NS presented LN class IV. Among patients presenting with AUA, we observed greater variability in histopathological findings. Our study did not show a relationship between creatinine levels and the activity/chronicity index of RBs (see graphs 5 and 6).
Conclusions
We observed the importance of screening for nephropathy in SLE patients. Our results notably show the high prevalence of AUA as a presentation form of LN, emphasizing the importance of interdisciplinary work for early diagnosis. Clinical and analytical parameters used in routine practice do not allow predicting histological findings in a high percentage of cases, so RB provides essential information to identify the class of LN, establish prognosis, and plan timely treatment. It would be necessary to continue the study in our population to obtain more conclusive information.