Stroke is a leading cause of death and neurological disability worldwide. Chronic kidney disease (CKD) is associated with an increased risk of stroke. Conversely, CKD confers worse outcomes following a stroke, with the highest mortality seen in end-stage renal disease. In comparison, the relationship between AKI and stroke is not well described, with a lack of UK data. In this single-centre, retrospective observational study of hospitalisations with acute stroke, I sought to determine the incidence of renal dysfunction and its impact on outcomes. AKI incidence was determined using preadmission serum creatinine (SCr) as ‘baseline’ renal function, compared with 4 surrogate methods. AKI was common, with an overall incidence of 20%, and was associated with increased 30-day and 1-year mortality using all AKI methods. Admission SCr most closely agreed with preadmission SCr but all surrogate methods exhibited bi-directional misclassification of AKI. CKD prevalence was high (over 30%) and was associated with increased mortality in univariable analyses. CKD patients underwent fewer imaging modalities and thrombectomy, possibly suggesting the presence of ‘renalism’. Contrast exposure was not found to be a risk factor for AKI. Vascular calcification and carotid artery disease were univariably associated with CKD. Multi-centre studies are needed to confirm the findings
