A Study to Examine Past Estimated Glomerular Filtration Rate (eGFR) Slope as a Risk Marker for Rapid Kidney Function Decline in People With Chronic Kidney Disease

Inclusion Criteria: 1. Signed and dated written informed consent in accordance with International Council on Harmonisation - Good Manufacturing Practice (ICH-GCP) and local legislation prior to admission to the trial. 2. Patients with available medical records for data abstraction to meet the objectives of the study. 3. Male or female patients aged ≥ 18 years at time of consent. 4. Body Mass Index (BMI) ≥ 18.5 and \< 50 kg/m² at Visit 1. 5. Clinical diagnosis of Chronic Kidney Disease (CKD). 6. Estimated Glomerular Filtration Rate (eGFR) decline of at least 1ml/min/1.73m²/year based on historical data from (electronic) medical records. 7. eGFR (Chronic Kidney Disease Epidemiology Collaboration \[CKD-EPI\] formula) 20 - 90 ml/min/1.73m² at Visit 1 calculated from serum creatinine measured by a central laboratory. 8. Patients are expected to be on optimal and stable background treatment (according to local therapy guidelines). 9. At least 4 serum creatinine values in the retrospective phase: * The most recent creatinine value not more than 6 months prior to Visit 1 (Screening Visit). * The most recent and oldest serum creatinine values should be no less than 1 year apart and no greater than 5 years apart. * There should be no gap of creatinine values of 2 years or longer. Exclusion Criteria: 1. Changes in CKD or other key background treatments (including dose changes) known to impact eGFR values, over the past 4 weeks for Angiotensin Converting Enzyme inhibitors (ACEis) and Angiotensin Receptor Blockers (ARBs) and 8 weeks for Sodium-Glucose Co-Transporter-2 (SGLT2) inhibitors prior to Screening. 2. Autosomal Dominant Polycystic Kidney Disease (ADPKD), uncontrolled lupus nephritis, in the opinion of investigators. 3. Any iv immune suppression therapy within the last 3 months prior to Visit 1 or anyone currently on \>45 mg prednisolone (or equivalent). 4. Acute kidney injury (AKI) according to the Kidney Disease: Improving Global Outcomes (KDIGO) definition in the 30 days prior to Visit 1 until the start of trial assessments. 5. Planned start of chronic renal replacement therapy during the trial or end stage renal disease (i.e \< 15 ml/min at 2 measurements 30 days apart) before start of trial assessments. 6. Medical history of cancer or treatment for cancer in the last two years prior to Visit 1 (except appropriately treated basal cell carcinoma of the skin, in situ carcinoma of uterine cervix, and prostatic cancer of low grade \[T1 or T2\]). 7. Major surgery (investigator's judgement) planned during the trial. 8. Currently enrolled in an investigational device or drug trial, i.e., less than 30 days before Visit 1 since ending an investigational device or drug trial(s) or receiving investigational treatment(s). Further exclusion criteria apply.