Chronic Kidney Disease is A Biomarker Rather Than A Risk Factor for Stroke

Background: Over the last approximate 15 years some have suggested that chronic kidney disease (CKD) is a risk factor for stroke in and of itself. The assertion that CKD is a risk factor for stroke requires more scrutiny. It is possible that CKD is a reflection of severity of conditions such as hypertension and diabetes that are themselves among the most treatable risk factors for stroke or it is possible that the effects of CKD change vascular and related physiological functions and therefor directly contribute to increased risk of stroke and it is also possible that treatments for advance CKD such has hemodialysis could contribute to increased risk of stroke as secondary effects of the treatment methods. To addresses these issues as participant in the Brain & Kidney Conference 2020 debate on this issue we were assigned the task of arguing that "Resolved: CKD is not a risk factor for stroke". Methods: We performed a structured literature review in Pub Med of the currently generally accepted recognized risk factors for stroke as well as publications relating CKD and risk of stroke. Results: We found that CKD and stroke is highly confounded by the cause of CKD such that the highest incidence of stroke happens in persons whose CKD is related to HTN and diabetes mellitus. Non-vascular causes of CKD have a much lower stroke incidence than those with vascular causes of CKD. When the major clinical risk factors are controlled for the relative risk of stroke drops dramatically by more than 35% to an odds ratio of only 1.1. We also found that in large population studies looking at the potential benefits of addressing treatable risk factors for stroke to reduce the incidence of stroke, CKD was either not mentioned or had a low contribution margin for treatment benefit. Conclusions: In general CKD is not a major risk factor for stroke but we argue that it is a biomarker of severity of vascular injury especially among individuals with hypertension and diabetes mellitus. Techniques for managing CKD such as hemodialysis may be related to increased risk of stroke and the contribution of CKD to intracerebral hemorrhage and brain microhemorrhages deserves more study and these were not addressed in detail in this debate.