Outcomes for Older People with Screening Detected Versus Existing Chronic Kidney Disease: Cohort Study with Data Linkage

Background: Chronic Kidney Disease (CKD) is a common health problem, associated with increased risk of cardiovascular disease (CVD), end stage kidney disease (ESKD), and premature death. A third of people aged ≥70 years have CKD, many of whom are undiagnosed, but little is known about the value of screening.

Aim: To compare the risk of adverse health outcomes between people with an existing diagnosis of CKD and those identified on screening. To identify factors associated with mortality in CKD.

Design: Prospective cohort study of 892 primary care patients aged ≥ 60 years with CKD (existing and screening detected) in Oxfordshire, with data linkage to civil death registry and secondary care.

Methods: Hazard Ratios (HR) and 95% Confidence Intervals (CI) were estimated using Cox proportional-hazard models to compare the risk of all-cause mortality, hospitalisation, CVD, ESKD separately, and as a composite between CKD groups, as well as to identify factors associated with mortality.

Results: After a median follow-up of 3-5 years, 49 people died, 493 were hospitalised, 57 had an incident CVD event, and 0 had an ESKD event. There was no difference in the composite outcome between those existing CKD and those identified on screening (HR 0.94, CI 0.67-1.33). Older age (HR 1.10, CI 1.06-1.15), male sex (HR 2.31, CI 1.26-4.24), and heart failure (HR 5.18, CI 2.45-10.97) were associated with increased risk of death.

Conclusion: Screening older people for CKD may be of value, as their risk of short-term mortality, hospitalisation, and CVD is comparable to people routinely diagnosed. Larger studies with longer follow-up in more diverse and representative populations of older adults are needed to corroborate these findings.