A Cross-Sectional Study on the Prevalence and Risk Stratification of Chronic Kidney Disease in Cardiological Patients in São Paulo, Brazil

Chronic kidney disease (CKD) provides a worse prognosis for patients with heart disease. In Latin America, studies that analyzed the prevalence and risk stratification of CKD in this population are scarce. We aimed to evaluate CKD prevalence and risk categories in patients of a public referral cardiology hospital in São Paulo, Brazil. This was a cross-sectional study based on a laboratory database. Outpatient serum creatinine and proteinuria results performed between 1 January 2021 and 31 December 2021 were analyzed. CKD was defined by estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) and proteinuria, by the albumin/creatinine ratio in a spot urine sample (UACR) >30 mg/g. A total of 36,651 adults were identified with serum creatinine levels (median age 72.4 [IQR, 51.0–73.6] years, 51% male). Among them, 51.9% had UACR dosage (71.5% with UACR < 30 mg/g, 22.6%, between 30–300 mg/g, and 5.9% with UACR > 300 mg/g). The prevalence of CKD was 30.9% (15.3% stage 3a, 10.2% stage 3b, 3.6% stage 4, and 1.7% stage 5), and the distribution of patients in the risk categories of the disease was: 52.0% with low-risk, 23.5%, moderate risk, 13.0%, high risk, and 11.2%, very high. In an outpatient setting, the prevalence of CKD in cardiological patients was almost three times (31%) that of the general population; about half of the individuals evaluated (48%) were not screened for an important risk marker (proteinuria), and approximately a quarter of these patients (24%) were in the high or very high CKD risk categories.