Background: Diffuse proliferative lupus nephritis (DPLN) is associated with significant morbidity and mortality unless aggressive immunosuppressive therapy is initiated early in the course of the disease. It has been observed that with steroid pulse therapy, some patients with DPLN enter clinical remission while others do not. The factors predictive of clinical remission with steroid pulse therapy in these patients has not yet been elucidated.
Methods: The authors retrospectively reviewed the records of 52 consecutive patients of DPLN treated by steroid pulse therapy in order to compare the characteristics of patients in the clinical remission group and those in the non-remission group. Clinical remission was defined as a serum creatinine level of < or = 1.2 mg/dL, negative or trace proteinuria, and the observation of < or = 1-4 red blood cells/high-power field in a routine urine examination. The 52 patients were divided into the clinical remission group (n = 29) and the non-remission group (n = 23), and also into subcategories of DPLN, namely, the IV-G group (n = 28) and the IV-S (n = 24). The characteristics of the patients were then compared between the two respective groups to identify factors that might be significantly related to clinical remission using Mann-Whitney's U test and the Cox proportional hazards model.
Results: In regard to the clinical and immunological characteristics of the patients, except for a significant difference in the serum albumin level, there were no significant differences in any of the parameters examined, including blood pressure, degree of proteinuria, and serum creatinine, between the remission group and non-remission group. Added to that, in the non-remission group, the pretreatment period was significantly longer than in the remission group. In relation to the histological characteristics, the Chronicity Index (CI) and severity of interstitial fibrosis were significantly higher (p = 0.021) in the non-remission group than in the remission group. The result of the Cox proportional hazards analysis revealed that the serum albumin, pretreatment period, CI, and severity of interstitial fibrosis were strongly related to the clinical outcome, whereas the results of the multivariate Cox proportional hazards analysis revealed only a weak correlation between the CI and the outcome.
Conclusion: It was concluded that the diagnosis should be performed early and the pretreatment period should be shortened before treatment. Also, an aggressive therapeutic intervention should be initiated early, before chronic renal injury becomes established, to increase the likelihood of remission in patients with DPLN.