#6045 TWO-YEAR INPATIENT ACTIVITY OF A DEDICATED ONCONEPHROLOGY DEPARTMENT
Authors: Marques Nídia , Fernandes Sara Cardoso , Ferreira Hugo , Chuva Teresa , Coelho Inês , Paiva Ana , Costa José 
Published: June 2023

Abstract

Background and Aims
Onconephrology is a rapidly evolving nephrology subspecialty that focuses on the interaction between cancer and the kidney. Our aim was to describe the clinical activity of a Nephrology Department in a cancer care center, in a 2-year period.

Method
We retrospectively analyzed the patients observed by the Nephrology Department at our center between 2021 and 2022. Demographic, clinical and laboratory data were collected. The statistical analysis was performed with SPSS software.

Results
During the 2-year period, there were 26,015 admissions, 636 of which required a Nephrology observation. Sixty-two per cent were female; the mean age was 68 years (SD ±12.4) with a median Charlson Comorbidity Index of 7. Most cancers were from gastrointestinal (24.1%, n = 153) or urologic origins (22.3%, n = 142), 37% had metastatic disease. Hematologic malignancies accounted for 12.1% of patients (n = 77). Nearly 44.5% of patients (n = 283) had chronic kidney disease (CKD), 20.8% (n = 59) of which were on hemodialysis (HD). Urinary tract obstruction (23.3%), cardiovascular risk factors (17.3%) and nephron loss (10.6%) were the most common causes of CKD. The main reasons for admission were renal dysfunction (23.7%; n = 151), infectious complications (23.3%, n = 148) and elective surgery (20.3%; n = 129). Of the patients observed, 40.7% (n = 259) had acute kidney injury (AKI), 23.3% (n = 148) acute-on-chronic kidney disease and 11.8% (n = 75) hydro-electrolytic disorders. Ten patients (1.6%) were evaluated for nephrotic syndrome (NS) or rapidly progressive renal failure (RPRF). Among AKI patients, intrinsic causes were the most prevalent (48.7% of all cases), with sepsis and ischemic and toxic acute tubular necrosis being the most frequent. Pre-renal and post-renal etiologies occurred in 29.7% and 21.6% of cases, respectively. Gynaecological and prostate tumours were the main neoplastic cause of post-renal AKI. There were 5 TMA cases in allogenic stem cell transplanted patients or treated with gemcitabine and six cases of acute interstitial nephritis, the majority immune check-point inhibitors-related. Over 54% (n = 142) of patients presented with AKI stage 3. About 13% (n = 34) needed renal replacement therapy (RRT), mainly continuous or hybrid techniques (58.8%; n = 20), and only 38% (n = 13) recovered renal function. The group of acute-on-chronic CKD patients included mostly stage 3b and 4 CKD. Most of them (54.1%; n = 80) had an intrinsic cause for kidney dysfunction. There was an equal distribution between stages of AKI severity. About 5% (n = 8) needed RRT and only two of those recovered. Hyponatremia was the most common electrolyte disturbance (56%; n = 42), followed by hypercalcemia (17.3%; n = 13). Over 40% of all cases of hyponatremia occurred in patients with metastatic lung cancer, probably related with the high prevalence of SIADH in this population. All but two patients with NS or RPRF underwent kidney biopsy. Among the patients with NS, its etiologies were: focal and segmental glomerulosclerosis secondary to pamidronate (n = 2), podocytopathy related to pazopanib (n = 1), paraneoplastic membranous nephropathy (n = 1), AL amyloidosis (n = 1) and TMA secondary to gemcitabine (n = 1). The causes of RPRF were ANCA-negative small vessel vasculitis, crescentic glomerulonephritis (GN) related to pembrolizumab and TMA. We also followed two patients with acute kidney disease, one with ATN secondary to bisphosphonates therapy and other with paraneoplastic fibrillary glomerulopathy. The median duration of hospitalization was 10 days (IQR 7.0 – 20.8), with median Nephrology follow-up time of 5.5 days (IQR 3.0 – 9.0). The overall mortality rate was 21.5%, and it was even higher on the subgroup with AKI (27.4%; p = 0.03). About 44% (n = 219) of patients were referred to outpatient Nephrology follow-up, at discharge.

Conclusion
Our data provides a picture of the rich inward activity developed at our cancer center by the nephrology team. The complexity of these patients highlights the importance of a multidisciplinary approach in their management. No surprisingly, there was a high mortality rate, which was even higher in the AKI-patients subset.