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Systemic lupus (SL) is a chronic systemic autoimmune and inflammatory disease characterized by the production of antinuclear antibodies directed in particular against native DNA. The prevalence of LS is 47 per 100,000 inhabitants in France. Geographically: French Guyana comes in 3rd position in terms of the highest prevalence in the overseas departments, i.e. 86.2/100,000. Lupus nephritis (LN) is one of the most common and severe manifestations. It is one of the major determinants of the prognosis of the disease. It is inaugural in 3 to 6% of cases, and it will be present in 30 to 75% of lupus patients during follow-up. The clinical manifestations are polymorphic, and the diagnosis is based on biological signs and histology. The objective of this study is to describe the clinical, biological, histological and therapeutic profile of NL and to determine the associated factors.
Retrospective, descriptive and analytical single-center study of the cohort of patients followed for systemic lupus at the West Guiana Hospital over 5 years, i.e. from 2018 to 2022. The primary endpoint was the occurrence of lupus nephritis, defined by the notion of permanent proteinuria > 0.5 g/24h. We described the clinical, biological, therapeutic and evolutionary characteristics and sought by united and multivariate analysis the factors associated with LN in the study population. The significance threshold was set at p<0.05.
In total, 52% of patients had NL with a female/male sex ratio of 9/10. They were mostly young, with an average age of 28. The patients were slightly overweight, with an average BMI of 27 kg/m2. 59% were hypertensive. As extra-renal signs, we noted: polyarthralgia (97%), discoid rash (88%), malar rash (72%), alopecia (59%), fever (53%), pleurisy- pericarditis (28%), seizures (9%). The average hemoglobin was 9.7 g/l. The anti DNA antibody was positive at 88%, the anti Sm at 72%, the anti SSA at 59%, the anti SSB at 19%, the U1RNP at 66%, the anti-phospholipids at 22% and the Direct Combs at 28%, the supplement was generally consumed. An average albuminemia was noted at 24 g/l. On the renal level: the average creatinine was 189 µmol/l, microscopic hematuria was present at 66% and aseptic leukocyturia at 69%. On the histological level: 50% had benefited from a renal biopsy puncture. 19% had a class IV, 9.4% a class III, 9.4% a class IV+V combination, 6.2% a class II, 3% a class V and 3% a class IV combination, the active lesions were found at 41%, the chronicles at 38%. All patients had a positive activity score. Therapeutically: all patients were on hydroxychloroquine, 94% on corticosteroids, 88% on MMF and 41% received cyclophosphamide and 2% rituximab. In multivariate analysis, The factors significantly associated with NL were: hypoalbuminemia, the notion of flare-up and the positivity of native anti-DNA antibodies. 41% of patients went into remission, 69% had relapses, 69% of patients developed chronic kidney disease and 28% progressed to dialysis. 66% developed an infectious complication related to the treatment.
Lupus nephropathy is common in LS in French Guiana, with a severe clinical and biological phenotype and an often unfavorable evolutionary profile despite conventional treatments. It is significantly associated with hypoalbuminemia, positivity of anti-DNA antibodies as well as the notion of relapses.