Inseparable in Disease, Yet Treated Apart: A Retrospective Study of a Cardiorenal Cohort at a Tertiary University Hospital

Introduction: The prevalence of cardiorenal syndrome (CRS) and its management might be challenging, so an interdisciplinary approach is advocated. The aim of this study was to identify and describe the population which might profit from such an interdisciplinary clinic at the University Hospital of Zürich. Methods: We screened 551 patients who were seen at least once in the nephrology and cardiology outpatient clinics from 2015 to 2022. Patients with kidney (87) or heart (47) transplantation, on dialysis (179), without concomitant chronic kidney disease (CKD) and heart failure (HF) (179), and those who died before the end of follow-up (94), were excluded, resulting in a cohort of 150 patients. Characteristics related to the type and cause of renal and cardiac disease, cardiovascular risk factors, adequacy of therapy, and incidence of hospitalization for HF were recorded. Results: The median age of the population was 71 years, with one-third having diabetes and two-thirds being male. The median BMI was 28 kg/m2. The predominant cause of chronic kidney disease (CKD) was cardiorenal syndrome type 2, affecting 44% (66 out of 150 patients). At the start of the follow-up, the distribution of CKD stages was as follows: 52 patients (34.7%) had CKD stage 2, 30 (20%) had CKD stage 3a, 21 (14%) had CKD stage 3b, 11 (7.3%) had CKD stage 4, and 1 (0.6%) had CKD stage 5. Notably, 81 patients (54%) had moderate or severe albuminuria. Ischemic cardiomyopathy was the leading cause of heart failure, affecting 36.4% (47 patients). Among the heart failure classifications, 73 patients (48.7%) had HFrEF, 32 (21.3%) had HFmrEF, and 45 (30%) had HFpEF. A total of 54 patients (36%) were treated with SGLT2 inhibitors, while 116 (77.3%) received RAAS inhibitors, including 32 patients (21.3%) on an ARNI. Those using both RAAS inhibitors and SGLT2 inhibitors were younger (average age 66 vs. 73 years, p = 0.005) and had a higher prevalence of diabetes (44% vs. 30%) and HFrEF compared to HFpEF (70% vs. 7%, p = 0.002). The hospitalization rate was notably high at 2.2 admissions per patient per year, with an incidence of acute kidney injury (AKI) at 0.23 events per patient per year. Conclusions: We identified a high-risk patient population with cardiorenal disease that might particularly benefit from evidence-based and patient-centered interdisciplinary care.