Long-term predictive value of acute kidney injury classification in diffuse proliferative lupus nephritis with acute kidney injury

STAT3 inhibition ameliorates renal interstitial inflammation in MRL/lpr mice with diffuse proliferative lupus nephritis

BACKGROUND AND OBJECTIVES

Acute kidney injury (AKI) is one of the most common and severe clinical syndromes of diffuse proliferative lupus nephritis (DPLN), of which poor prognosis is indicated by aggravated renal function deterioration. However, the specific therapy and mechanisms of AKI in DPLN remain to be explored.

METHODS

The correlation between AKI and clinical pathological changes in DPLN patients was analyzed. Expression of STAT3 signaling was detected in MRL/lpr mice with DPLN using immunohistochemical staining and immunoblotting. Inhibition of STAT3 activation by combination therapy was assessed in MRL/lpr mice.

RESULTS

Correlation analysis revealed only the interstitial leukocytes were significantly related to AKI in endocapillary DPLN patients. MRL/lpr mice treated with vehicle, which can recapitulate renal damages of DPLN patients, showed upregulation of STAT3, pSTAT3 and caspase-1 in renal cortex. FLLL32 combined with methylprednisolone therapy significantly inhibited the STAT3 activation, improved acute kidney damage, reduced the interstitial infiltration of inflammatory cells and decreased the AKI incidence in MRL/lpr mice.

CONCLUSION

STAT3 activation may play an important role in the pathogenesis of DPLN and the development of AKI. Hence, STAT3 inhibition based on the combination of FLLL32 with methylprednisolone may represent a new strategy for treatment of DPLN with AKI.

Clinicopathological Characteristics and Prognosis of Lupus Nephritis Patients with Acute Kidney Injury

INTRODUCTION

Acute kidney injury (AKI) is common in lupus nephritis (LN) and a risk factor for chronic kidney failure. Here, we aimed to assess the characteristics and prognosis of LN patients with AKI.

METHODS

AKI and AKI severity stages in LN patients were defined by the Kidney Disease Improving Global Outcomes (KDIGO) classification. Long-term renal outcomes and patient mortality between different stages of AKI were compared by Cox regression analysis.

RESULTS

Of 1272 LN patients, 225 (17.69%) had AKI and 72 (5.66%) were AKI stage 3. Compared with the non-AKI group, the proportion of male patients was significantly higher in the AKI group (p = 0.002). In addition, there were markedly higher proportions of hematologic system damage, more severe renal manifestations, and higher Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores in the AKI group than in the non-AKI group. The active and chronic lesions in renal biopsy were significantly higher in LN patients with AKI than those without AKI. During a median follow-up of 53 months, Kaplan-Meier curve showed that LN patients with AKI stage 3 had significantly poorer long-term renal outcomes (p = 0.002) and patient survival (p < 0.001) than those without AKI. Furthermore, AKI stage 3, but not stage 1 or 2 was significantly associated with adverse renal outcomes (hazard ratio [HR] = 2.52, 95% confidence interval [CI] 1.01-6.28, p = 0.048) and all-cause mortality (HR = 2.80, 95% CI: 1.18-6.61, p = 0.019) in LN patients. In patients with AKI, increased baseline serum creatinine and severe glomerular sclerosis were independent risk factors for worse renal outcomes, while higher blood pressure, increased baseline serum creatinine, and anti-Sjogren's syndrome A positivity could indicate poor survival.

DISCUSSION

LN patients with AKI stage 3, but not stages 1 and 2, have poorer long-term renal outcomes and patient survival. Our study demonstrates the importance of early identification and management of AKI in LN patients.

Predictors of treatment outcomes in lupus nephritis with severe acute kidney injury and requirement of dialytic support

INTRODUCTION/OBJECTIVES

Acute kidney injury (AKI) with the requirement of kidney replacement therapy (KRT) portends a poor prognosis for kidney function in lupus nephritis (LN). This study evaluated the kidney function recovery rates, the rates of reinitiation of KRT, and factors associated with these outcomes in LN.

METHOD

All consecutive patients hospitalized for LN with KRT requirement between 2000 and 2020 were included. Their clinical and histopathologic characteristics were retrospectively registered. The outcomes and associated factors were evaluated by multivariable Cox regression analysis.

RESULTS

Among 140 patients, 75 (54%) recovered kidney function, with recovery rates of 50.9% and 54.2% by 6 and 12 months of therapy. The factors associated with a lower probability of recovery included a previous history of LN flares, worse eGFR and higher proteinuria at presentation, immunosuppression with azathioprine, and hospitalizations within 6 months of therapy initiation. There was no difference in the kidney function recovery rates between mycophenolate and cyclophosphamide treatment schemes. Out of 75 patients who recovered kidney function, 37 (49%) reinitiated KRT, with KRT reinitiation rates of 27.2% and 46.5% by 3 and 5 years. Seventy-three (52%) patients had at least one hospitalization within 6 months of initial therapy, 52 (72%) of them secondary to infectious events.

CONCLUSIONS

Approximately 50% of patients with LN and KRT requirement recover kidney function within 6 months. The risk-to-benefit ratio decisions may be aided by clinical and histological factors. These patients require close follow-up as ≈50% of those who recover kidney function will reinitiate dialysis in the long term. Key Points • Approximately 50% of patients with severe acute lupus nephritis with the need for kidney replacement therapy requirement recover their kidney function. • The factors associated with a lower probability of recovery of kidney function include a previous history of LN flares, worse eGFR and higher proteinuria at presentation, immunosuppression with azathioprine, and hospitalizations within 6 months of therapy initiation. • Patients who recover kidney function will require close follow-up as around 50% of them will eventually reinitiate kidney replacement therapy.

Acute Kidney Injury Classifications in the Prediction of In-hospital Mortality and Renal Function Non-recovery

Background

In the last two decades diagnostic criteria for acute kidney injury (AKI) were developed: Risk, Injury, Failure, Loss of Kidney Function, End-Stage Kidney Disease (RIFLE), Acute Kidney Injury Network (AKIN), and Kidney Disease: Improving Global Outcomes (KDIGO) classifications.

Objective

The study aimed to determine the incidence of AKI based on the RIFLE, AKIN, and KDIGO criteria, as well as analyze their predictive value for mortality and renal function outcome.

Methods

This was a single-center prospective study of patients diagnosed with AKI. Acute kidney injury was defined and classified according to the RIFLE, AKIN, and KDIGO criteria. The outcomes were renal function outcome and in-hospital mortality.

Results

The incidence rates of AKI based on the RIFLE, AKIN, and KDIGO criteria were 13.4%, 14-36%, and 14.64%, respectively. Multiple regression analysis showed that higher stages of AKI according to the KDIGO criteria were independently associated with non-recovery of renal function (p=0.011). However, the predictive ability of RIFLE, AKIN and KDIGO classifications for renal function recovery was poor (Area Under the Receiver Operating Characteristics-AUROC=0.599, AUROC=0.637, AUROC=0.659, respectively). According to the RIFLE and AKIN criteria, in-hospital mortality was statistically significantly higher in stage Failure/3 (p=0.0403 and p=0.0329, respectively) compared to stages Risk/1 and Injury/2. Receiver Operating Characteristics (ROC) analysis showed that all three classifications had poor predictive ability for in-hospital mortality (AUROC=0.675, AUROC=0.66, AUROC=0.681).

Conclusions

KDIGO classification is an independent predictor of renal function non-recovery. However, by ROC analysis, all three classifications have poor predictive ability for renal function outcome and mortality.

One-year renal outcome in lupus nephritis patients with acute kidney injury: a nomogram model

OBJECTIVE

To develop a short-term renal outcome prediction model for acute kidney injury (AKI) in patients with lupus nephritis.

METHODS

Two lupus AKI cohorts from 2 independent centers during 2013-2019 were included, i.e., a derivation cohort from a rheumatology center and a validation cohort from a nephrology center. Clinical characteristics and renal histologic features were obtained. The outcome measurement was the recovery of kidney function within 12-month. Lasso regression was used for feature selection. Prediction models with or without pathology were built and nomogram was plotted. Model evaluation including calibration curve and decision curve analysis was performed.

RESULTS

130 patients and 96 patients were included in the derivation and validation cohorts, of which 82 and 73 patients received renal biopsy, respectively. The prognostic nomogram model without pathology included determinants of SLE duration, days from AKI onset to treatment and baseline creatinine level (C-index 0.85 (95%CI 0.78∼0.91) and 0.79 (95%CI 0.70∼0.88) for the 2 cohorts). Combination of histologic interstitial tubular fibrosis in the nomogram gave an incremental predictive performance (C-index 0.93 vs 0.85, p = 0.039) in the derivation cohort, but failed to improve the performance in the validation cohort (C-index 0.81 vs 0.79, p = 0.78). Decision curve analysis suggested clinical benefit of the prediction models.

CONCLUSION

The predictive nomogram models might facilitate more accurate management for lupus patients with AKI.

Acute kidney injury in idiopathic membranous nephropathy with nephrotic syndrome

BACKGROUND AND OBJECTIVES

The impact of acute kidney injury (AKI) on the progression of renal function in idiopathic membranous nephropathy (iMN) with nephrotic syndrome (NS) patients have not yet been reported, we sought to investigate the incidence, clinical features and prognosis of AKI in iMN with NS patients and determine clinical predictors for progression from AKI to advanced chronic kidney disease (CKD) stage.

METHODS

We analyzed clinical and pathological data of iMN with NS patients retrospectively collected from Jan 2012 to Dec 2018. The primary renal endpoint was defined as persistent eGFR <45ml/min per 1.73 m² more than 3 months. Comparisons of survival without primary renal endpoint were performed by Kaplan-Meier curves and log-rank test. Univariate and multivariate Cox proportional hazard models were constructed to determine independent variables associated with primary renal endpoint .

RESULTS

434 iMN with NS patients were enrolled. The incidence of AKI 1 stage, AKI 2 stage and AKI 3 stage was 23.1, 4.8 and 0.7% respectively. 66 (53.2%) patients with AKI had complete renal function recovery and 42 (33.9%) patients with AKI reached primary renal endpoint. Survival without primary renal endpoint was worse in AKI patients than No AKI patients (67.1 ± 5.3 and 43.7 ± 7.3% vs 99.5 ± 0.5 and 92.5 ± 4.2% at 2 and 4 years,p < 0.001). AKI was independently associated with primary renal endpoint, with an adjusted hazard ratio(HR) of 25.1 (95%CI 7.7-82.1, p < 0.001).

CONCLUSIONS

AKI was usually mild and overlooked in iMN patients with NS, but it had a strong association with poor clinical outcomes and was an independent risk factor for CKD progression.