Abstract
<b><i>Introduction:</i></b> Chronic kidney disease (CKD) is associated with an increased incidence of atrial fibrillation (AF). Also, patients with AF are prone to adverse kidney outcomes. We examined comorbidities and medication use in patients with CKD and incident AF. <b><i>Methods:</i></b> The Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) is a nationwide retrospective register-linkage study including data from 168,233 patients with incident AF from 2007 to 2018, with laboratory data from 2010 onwards. Estimated glomerular filtration rate (eGFR) was available for 124,936 patients. The cohort was divided into 5 CKD stages with separate groups for dialysis and kidney transplantation. <b><i>Results:</i></b> At AF diagnosis eGFR <60 mL/min/1.73 m<sup>2</sup> was found in 27%, while 318 (0.3%) patients were on dialysis, and 188 (0.2%) had a functioning kidney transplant. Lowering eGFR yielded more comorbidities and medications. During 2010–2018 in patients with eGFR <60 mL/min/1.73 m<sup>2</sup> prevalence of hypertension, dyslipidaemia, and diabetes increased from 82 to 88%, from 50 to 66% and from 25 to 33%, respectively (<0.001). Throughout the observation period, lipid-lowering medication was underused. <b><i>Conclusion:</i></b> More than one-fourth of patients with incident AF also had CKD stage 3–5 (eGFR <60 mL/min/1.73 m<sup>2</sup>). Both comorbidities and medication use increased with worsening kidney function. Prevalence of major cardiovascular (CV) risk factors increased during 2010–2018, but the use of survival-affecting medications, such as lipid-lowering medication, was suboptimal at all stages of CKD. More attention should be given to the optimal treatment of risk factors in this high CV risk population.