Acute Kidney Injury in Systemic Sclerosis Beyond Scleroderma Renal Crisis: A Case-Control Study.

Background And Objectives: Renal involvement in systemic sclerosis remains a significant concern with the focus often centered on scleroderma renal crisis (SRC). However, the broader spectrum of renal manifestations, beyond SRC, remains underrecognized. In our case-control analysis, we describe other causes, risk factors, and renal outcomes of acute kidney injury (AKI) in systemic sclerosis other than SRC.

Methods: Patients diagnosed with SSC, with and without AKI, between 2017 and 2023 at Albany Medical Center, were included in the case-control study using International Classification of Diseases , 10th Revision codes and electronic medical records. Patients with SRC were carefully excluded. Data were collected and compared between AKI and non-AKI groups for patients' demographics, clinical characteristics, and baseline treatment. Additionally, data were collected for baseline, peak, and follow-up creatinine, etiology of AKI, treatment, and outcomes. Statistical analysis was performed using R (version 4.3.0) and Minitab (V19). Categorical variables were presented as frequencies/percentages, and continuous variables as means/standard deviations. Associations between categorical variables were assessed by χ 2 test and Fisher exact test. Odds ratios and 95% confidence intervals were calculated using binary logistic regression to separately assess the effect of each independent variable on the odds of AKI. Statistical significance was set at p < 0.05.

Results: A total of 74 cases were identified. Out of these 74 cases, 27 had AKI and 47 did not have AKI. Out of the 27 AKI cases, 4 with SRC were excluded. Advanced age, chronic kidney disease, and heart failure were identified as risk factors for AKI development. The predominant cause of AKI was prerenal etiology, accounting for 47.8% (n = 11) of cases. This was followed by cardiorenal syndrome and acute tubular necrosis, accounting for 21.7% and 17.3% of the cases, respectively. Most of the cases with AKI had complete renal recovery 78% (n = 18), whereas 17% (n = 4) had progression of the underlying chronic kidney disease. One patient progressed to end-stage renal disease requiring hemodialysis.

Conclusions: This analysis highlights the risk factors and variable clinicopathological courses of renal involvement in patients with scleroderma. This may range from mild AKI with good prognosis to life-threatening SRC.