Letter by Barrios et al Regarding Article, “Impact of Proteinuria and Glomerular Filtration Rate on Risk of Thromboembolism in Atrial Fibrillation: The Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) Study”
We read the article by Go et al1 about the impact of proteinuria and glomerular filtration rate on the risk of thromboembolism in patients with atrial fibrillation. Interestingly, the authors found that after adjustment for known risk factors for stroke and other confounders, proteinuria increased the risk of thromboembolism by 54%, and there was a graded increased risk of stroke associated with a progressively lower level of estimated glomerular filtration rate compared with a rate ≥60 mL/min per 1.73 m2: relative risk of 1.16, for estimated glomerular filtration rate of 45 to 59 mL/min per 1.73 m2 and relative risk of 1.39 for estimated glomerular filtration rate <45 mL/min per 1.73 m2 (P=0.0082 for trend). In patients receiving long-term dialysis, atrial fibrillation appears to be a common complication, and some studies suggest that the arrhythmia further increases the risk of ischemic stroke.2,3 However, current atrial fibrillation guidelines do not include chronic kidney disease and proteinuria as potential risk factors for thromboembolic events.4
This omission could directly translate into an underuse of anticoagulation in daily clinical practice and, as a result, an increase in cardiovascular morbidity and mortality. For instance, in a hypertensive population with chronic ischemic heart disease attended by a cardiologist, in which the presence of atrial fibrillation is more frequent with renal dysfunction (26% in patients with an estimated glomerular filtration <60 mL/min per 1.73 m2 versus 12% in those with ≥60 mL/min per 1.73 m2), only 22% of patients with chronic renal disease were taking anticoagulants.5
All these data highlight, first, that the current scores performed to assess the risk of thromboembolism in patients with atrial fibrillation are likely incomplete. There are other risk factors not currently considered, such as coronary artery disease or chronic kidney disease, that may be taken into account, and this could be one of the reasons that cardioembolic events are still frequent. If these and other risk factors are not included, physicians may underestimate the thromboembolic risk and subsequently underuse antithrombotic therapy.4 Second, although some physicians do not prescribe anticoagulants in patients with renal disease because of the potential risk of bleeding complications, particularly in those receiving long-term dialysis, the current evidence plainly supports the use of anticoagulation therapy in these patients.
In conclusion, because chronic kidney disease increases the risk of thromboembolism in patients with atrial fibrillation, more efforts are warranted to extend the use of antithrombotic therapy in this population. The first step could include this condition in the risk scores.
Go AS, Fang MC, Udaltsova N, Chang Y, Pomernacki NK, Borowsky L, Singer DE, ATRIA study investigators. Impact of proteinuria and glomerular filtration rate on risk of thromboembolism in atrial fibrillation: the Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) study. Circulation. 2009; 119: 1363–1369.
Fuster V, Rydén LE, Cannom DS, Crijns HJ, Curtis AB, Ellenbogen KA, Halperin JL, Le Heuzey JY, Kay GN, Lowe JE, Olsson SB, Prystowsky EN, Tamargo JL, Wann S, Smith SC Jr, Jacobs AK, Adams CD, Anderson JL, Antman EM, Halperin JL, Hunt SA, Nishimura R, Ornato JP, Page RL, Riegel B, Priori SG, Blanc JJ, Budaj A, Camm AJ, Dean V, Deckers JW, Despres C, Dickstein K, Lekakis J, McGregor K, Metra M, Morais J, Osterspey A, Tamargo JL, Zamorano JL. ACC/AHA/ESC 2006 guidelines for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Circulation. 2006; 114: e257–e354.
Barrios V, Escobar C, Murga N, de Pablo C, Bertomeu V, Calderón A, Echarri R. Clinical profile and management of hypertensive patients with chronic ischemic heart disease and renal dysfunction attended by cardiologists in daily clinical practice. J Hypertens. 2008; 26: 2230–2235.