A SYSTEMATIC REVIEW TO EVALUATE THE DRIVERS OF NON-ADHERENCE TO ALBUMINURIA TESTING GUIDELINES AND THE CLINICAL AND ECONOMIC IMPACT OF NOT IDENTIFYING CKD OVER THE COURSE OF PROGRESSIVE KIDNEY FUNCTION LOSS

Abstract BACKGROUND AND AIMS The Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend regular estimated glomerular filtration rate (eGFR) and albuminuria testing in patients diagnosed with chronic kidney disease (CKD) and those with specific risk factors such as type 2 diabetes (T2D). In addition, the European Society of Cardiology (ESC) guidelines recommend albuminuria testing for cardiovascular (CV) disease risk assessment in CKD patients. An eGFR test can indicate kidney function decline, whereas albuminuria testing gives an indication of kidney damage. When used in combination, an accurate understanding of CKD risk progression can be obtained. Both KDIGO and ESC guidelines are based on evidence that albuminuria testing is critical to prevent CKD and CV events. Evidence from real-world practice suggests that albuminuria, specifically urine albumin-to-creatine ratio (UACR) testing is suboptimal. For example, UACR testing is not regularly undertaken in clinical practice, with low rates reported in the UK1 (67%), The Netherlands2 (57%) and France3 (29%). A systematic literature review (SLR) was undertaken to explore the barriers to regular albuminuria testing in CKD patients in line with the guidelines, and the clinical and economic impact of not identifying these patients over the course of progressive kidney function loss. Our hypothesis was that in the absence of adequate testing, patients are not identified and are more likely to progress to a worse clinical state with an economic impact on healthcare costs. METHOD This SLR searched MEDALL, Embase, Cochrane CENTRAL, and other databases from the date of inception to August 2021 for studies. Title and abstract screening, followed by full-text screening of included papers was undertaken by two independent reviewers. RESULTS Fourteen studies were included. Only one study explored direct physician barriers to UACR testing, with the biggest perceived barrier being that knowing a test would not significantly impact patient management, potentially due to lack of therapeutic options. Twelve studies reported on the clinical and one reported on the economic impact of not identifying CKD patients with or without T2D upon UACR or eGFR testing. All included studies looked at not identifying the patient population because of late referral. These studies showed that patients who were referred late had increased all-cause mortality, increased CV mortality and lower survival rate versus those patients that were referred on time. No studies looked at patients in the early stages of CKD, those that were referred late based on a UACR and eGFR test result, or those that were diagnosed late due to the lack of reporting of diagnostic test results. CONCLUSION A limited number of studies reporting drivers of non-adherence to albuminuria testing were identified. The largest barrier reported was the perception that testing will not impact patient management. Supporting our original hypothesis, individuals referred late with end-stage kidney disease were shown to experience worse clinical outcomes, including higher rates of mortality, than those referred on time. However, there were limited data on the impact of not identifying or diagnosing patients in the early stages of CKD, and a lack of reporting of the tests used, whether eGFR or UACR, to identify these individuals. Funding: Bayer AG PROSPERO: CRD42021275223