Warfarin utilisation and anticoagulation control in patients with atrial fibrillation and chronic kidney disease

Abstract

Objective To evaluate warfarin prescription, quality of International Normalized Ratio (INR) monitoring, and of INR control in patients with atrial fibrillation (AF) and chronic kidney disease. Methods We performed a retrospective cohort study of patients with newly diagnosed AF in the Veterans Administration (VA) health care system. We evaluated anticoagulation prescription, INR monitoring intensity, and time in and outside INR therapeutic range (TTR) stratified by chronic kidney disease severity (CKD). Results Of 123,188 patients with newly diagnosed AF, use of warfarin decreased with increasing severity of CKD (57.2% to 46.4%), although it was higher among patients on dialysis (62.3%). Although INR monitoring intensity was similar across CKD strata, the proportion with TTR ≥ 60% decreased with CKD severity, with only 21% of patients on dialysis achieving TTR ≥ 60%. After multivariate adjustment, the magnitude of TTR reduction increased with CKD severity. Patients on dialysis had the highest time markedly out of range with INR <1.5 or INR >3.5 (30%); 12% of INR time was > 3.5, and low TTR persisted for up to three years. Conclusions There is a wide variation in anticoagulation prescription based on CKD severity. Patients with moderate to severe CKD, including dialysis, have substantially reduced TTR, despite comparable INR monitoring intensity. These findings have implications for more intensive warfarin management strategies in CKD or alternative therapies such as direct oral anticoagulants.

Warfarin in nonvalvular atrial fibrillation—Time for a change?

“…In patients on HD, TTR is lower and INR variability higher than in patients with normal kidney function. In a large retrospective nationwide cohort of veterans with newly diagnosed NVAF, the proportion of patients with a TTR ≥ 60% decreased with increasing severity of kidney disease and only 21% of HD patients achieved this level; this occurred despite frequent testing. Strikingly, 30% of INR values were markedly out of range (INR < 1.5 or > 3.5) with 12% of values >3.5.…”

Oral anticoagulation in end-stage renal disease and atrial fibrillation: is it time to just say no to drugs?

“…It is in this context that we interpret the important study by Yang and colleagues published in this journal 7. The authors analysed warfarin utilisation, monitoring and time in therapeutic range (TTR) in patients with chronic kidney disease and newly diagnosed AF across the Veterans Health Administration (VA).…”

“…Importantly, INR control in patients without renal dysfunction was comparable to prior studies. Prior studies examining INR control in populations of patients with ESRD reported TTRs in the 40%–50% range 7. Poor INR control (TTR<60%) confers increased risk for stroke, systemic embolism, major bleeding episodes in addition to overall mortality in patients on warfarin 8.…”

Cautious anticoagulation strategy in patients with dialysis-requiring end-stage kidney disease

“…To the Editor:  We read with interest this manuscript which demonstrated in a large clinical registry that patients with chronic kidney disease with indications for anticoagulation were often treated subtherapeutically 1. A more aggressive approach was, therefore, advocated.…”