Prevalence, outcomes, and cost of chronic kidney disease in a contemporary population of 2·4 million patients from 11 countries: The CaReMe CKD study

Abstract

Background: Digital healthcare systems data could provide insights into the global prevalence of chronic kidney disease (CKD). We designed the CaReMe CKD study to estimate the prevalence, key clinical adverse outcomes and costs of CKD across 11 countries.

Methods: Individual-level data of a cohort of 2·4 million contemporaneous CKD patients was obtained from digital healthcare systems in participating countries using a pre-specified common protocol; summarized using random effects meta-analysis. CKD and its stages were defined in accordance with current Kidney Disease: Improving Global Outcomes (KDIGO) criteria. CKD was defined by laboratory values or by a diagnosis code.

Findings: The pooled prevalence of possible CKD was 10·0% (95% confidence interval 8.5‒11.4; mean pooled age 75, 53% women, 38% diabetes, 60% using renin-angiotensin-aldosterone system inhibitors). Two out of three CKD patients identified by laboratory criteria did not have a corresponding CKD-specific diagnostic code. Among CKD patients identified by laboratory values, the majority (42%) were in KDIGO stage 3A; and this fraction was fairly consistent across countries. The share with CKD based on urine albumin-creatinine ratio (UACR) alone (KDIGO stages one and two) was 29%, with a substantial heterogeneity between countries. Adverse events were common; 6·5% were hospitalized for CKD or heart failure, and 6·2% died, annually. Costs for renal events and heart failure were consistently higher than costs for atherosclerotic events in CKD patients across all countries.

Interpretation: We estimate that CKD is present in one out of ten adults. These individuals experience significant adverse outcomes with associated costs. The prevalence of CKD is underestimated when using diagnostic codes alone. There is considerable public health potential in diagnosing CKD and providing treatments to those currently undiagnosed.

Funding: The study was sponsored by AstraZeneca.

Keywords: Chronic kidney disease; Costs; Epidemiology; Global health; Outcomes; Prevalence; Primary care; Public health; Renal impairment.

Figure 1

Countries and number of chronic kidney disease (CKD) patients. Number of patients with both measured and diagnosed CKD, defined as having a CKD diagnosis or one pathological UACR or eGFR value, where the chronicity of CKD was not confirmed. Measured CKD, patients with Kidney Disease: Improving Global Outcomes (KDIGO) criteria CKD using urine albumin-to-creatinine ration and estimated glomerular filtration rate. Diagnosed CKD, patients who have registered CKD diagnosis, with or without available pathological eGFR and/or UACR values.

Figure 2

Description of data sources used across the countries. Data extractions on the following levels of health care: 1. Primary health care. 2. Secondary health care (specialist or outpatient hospital care). 3. Tertiary health care (in-hospital care).

Figure 3

Proportion of patients in the different chronic kidney disease (CKD) stages per country in 2018 to 2021. Measured CKD, patients with KDIGO confirmed CKD using UACR and eGFR. Diagnosed CKD, patients who have a registered CKD diagnosis. Stage I: eGFR ≥90 ml/min/1·73 m² and UACR 30-300 mg/g [3-30 mg/nmol] Stage II: eGFR 60-89 ml/min/1·73 m² and UACR 30-300 mg/g [3-30 mg/nmol] Stage IIIA: eGFR 45-59 ml/min/1·73 m² Stage IIIB: eGFR 30-44 ml/min/1·73 m²) Stage IV: eGFR 15-29 ml/min/1·73 m² Stage V: eGFR <15 ml/min/1·73 m² eGFR, estimated glomerular filtration rate, ml/min/1·73 m². UACR, Urine albumin-to-creatinine ration. UK, United Kingdom.

Figure 4

Hospital health care costs per chronic kidney disease (CKD) patient at index and cumulatively during up to 5 years. PAD, peripheral artery disease. UK, United Kingdom.