Marked PT-INR prolongation associated with appetite loss due to urinary tract infection in a late elderly case with chronic atrial fibrillation

Abstract

An 80-year old woman presented with macroscopic hematuria on June 4(th), 2008. She had been suffering from general malaise and appetite loss since about 10 days previously. She had received anticoagulant therapy with warfarin due to chronic atrial fibrillation and PT-INR was well controlled between 1.6-2.2. When she presented, PT-INR was 12.88, and urinary tract infection (UTI) and hypoalbuminemia (2.2 g/dl) were observed. Therefore, warfarin therapy was discontinued, and antibiotics and vitamin K were administered. Normalization of PT-INR resulted in the disappearance of hematuria and UTI improved as a result of antibiotics administration. As the appetite loss improved, for serum albumin level increased. The previous dose of warfarin achieved PT-INR around 1.8. Her drug compliance had been good, and she took no drug nor food which could interact with warfarin. We also found no liver dysfunction, acute renal failure, malignancy, nor hyper- or hypo-thyroidism. Hypoalbuminemia caused by appetite loss due to UTI seems very likely to increase concentration of circulating free warfarin resulting in extreme prolongation of PT-INR. Our findings in the present case may suggest that we should pay more attention on changes of drug pharmacokinetics in elderly patients because of their poor adaptation to their circumstances such as infection or dehydration.

Patients with dental hemorrhagic complicationsundergoing warfarin therapy exhibit excessiveinternational normalized ratio prolongation: A report of 2 cases

“…Since warfarin strongly binds to serum albumin [19], low levels of serum albumin increase the risk of INR prolongation [20,21]. A slight decline in albumin can also increase the INR value [18]. In our cases, serum albumin as well as A/G ratio was low, suggesting that hypoalbuminemia increased INR value.…”

“…In the elderly, poor oral intakes of dietary vitamin K is the most likely explanation for the marked prolongation of INR despite a stable dose of warfarin [17]. We could not exclude the possibility that both cases were insufficient for taking vitamin K. On the other hand, hypoalbuminemia due to appetite loss exhibits a marked prolongation of INR [18]. Since warfarin strongly binds to serum albumin [19], low levels of serum albumin increase the risk of INR prolongation [20,21].…”

A case of type 2 diabetes with polymyalgia rheumatica accompanied by marked prothrombin time-international normalized ratio elongation

“…In practice, the importance of paying close attention to serum albumin levels during oral warfarin therapy has been indicated [6]. In a similar case, Saito et al [7] reported the case of an elderly patient with chronic atrial fibrillation who was on chronic warfarin therapy and who developed a urinary tract infection, which resulted in appetite reduction and hypoalbuminemia, which led to sudden PT-INR elongation. Fukuda et al [8] reported that the prevalence of malnutrition, defined as hypoalbuminea less than 3.4 g/dl, was 24.7% in Japanese patients with RA, and the characteristic progression of malnutrition was attributed to excessive protein catabolism evoked by inflammatory cytokines.…”