#1432 Prevalence, risks and treatment of incident chronic kidney disease stage 3-4: an observational study in Finland between 2016-2022
Authors: Metsarinne Kaj , Toppila Iiro , Uusi-Rauva Kristiina , Frederiksen Line Elmerdahl , Bodegard Johan , Brinkmann Satu 
Published: May 2024

Abstract

Background and Aims
The rising burden of chronic kidney disease (CKD) calls for early detection and targeted interventions. Kidney-protective treatments (renin–angiotensin system inhibitors [RASis] and sodium-glucose co-transporter-2 inhibitors [SGLT2is]) can delay chronic kidney disease (CKD) progression, cardiovascular events and death. However, contemporary differences between CKD patients with and without type 2 diabetes (T2D) is limited. This study aimed to describe the prevalence, patient characteristics, the use of kidney protective treatments (RASi or SGLT2i) and event risks among patients with incident stage 3-4 CKD in Finland.

Method
We used comprehensive real-world clinical data from electronic health records from primary and hospital care in five municipalities in Finland between 1st January 2016 to 31st December 2022 to identify stage 3-4 CKD patients aged ≥18 years, defined as having either one estimated glomerular filtration rate (eGFR) measurement between 15 to 60 ml/min/1.73 m2 followed by a second one ≥90 days apart, or a registered CKD diagnosis. Two cohorts from primary care were identified: a prevalent cohort indexed at a fixed date, 1st Jan 2022 and an incident cohort indexed at the date of new CKD. The incident CKD patients were followed from CKD incident index date until death, emigration, or end of study on 31 December 2022. Analyses were also stratified by CKD patients with T2D and non-diabetes (T1D and gestational diabetes excluded), respectively. Risks were estimated as event rates per 1000 patient-years. The proportion of patients on/off treatment were estimates as a function of time and divided into pre- vs. post-index.

Results
In 2022 the prevalent cohort of 16,380 CKD stage 3-4 patients, represented a prevalence of 6.2% in the total background population of 263,383 individuals. The 12,129 incident Stage 3-4 CKD patients had a median eGFR of 55 ml/min/1.73 m2, similar in both non-T2D and T2D. Most patients were non-T2D; 73% (n = 8859). At index, 1.7% had a CKD diagnosis, lower in non-T2D (1.0%) vs T2D (3.5%) patients. The use of urine albumin creatinine ratio (UACR) was generally very low (21% had a measurement), 9% in the non-T2D and 53% in the T2D patients. Non-T2D, compared to T2D patients, were similar in age (76 vs 75 years) and had slightly less comorbidities like HF (12% vs 18%), myocardial infarction (9% vs 14%), stroke (15% vs 16%), atrial fibrillation (21% vs 25%) and less treated with statins (38% vs 64%). During follow-up, 10% had died within 1-year (97 deaths per 1000 patient years), similar in non-T2D (95 deaths per 1000 patient years) and T2D patients (104 deaths per 1000 patient years). One year risk of any hospitalization was also high, 49% and 64%, respectively. The use of kidney-protective treatments (renin angiotensin system inhibitor [RASi] or SGLT2i) at index (date of incident CKD) was lower in patients without T2D (47%) compared to those with T2D (69%). No change was observed in their use in the 12 months after incident CKD (Fig.). Finally, when studying the proportion of all non-T2D patients receiving SGLT2i after approval for CKD treatment, less than 1% of all CKD patients in the study group were treated with SGLT2i on 31st December 2022.

Conclusion
This study shows that CKD stage 3-4 is highly prevalent in Finland. Newly detected CKD stage 3-4 patients were little diagnosed and the use of UACR was low, especially among those who were non-diabetic. More than 2 out of 3 CKD patients were non-diabetic. Importantly, these non-diabetic CKD patients had similarly high disease burden, similar high risk of dying and had less kidney/cardiovascular prevention compared to those with T2D. The high mortality risks, substantial kidney-protective treatment inertia and UACR underutilization in stage 3-4 CKD patients all call for an urgent need for improved awareness and risk management, especially in the larger group of non-T2D.