Background

Direct-acting oral anticoagulants (DOACs) are increasingly used to prevent and treat thromboembolism. Although measurement of DOAC concentrations is not currently recommended as part of routine patient care, measurement of DOAC concentrations with anti-factor Xa activity assays have recently become clinically available.

Objectives

Our goal was to determine the clinical conditions under which DOAC concentration measurements are requested.

Materials and methods

Retrospective electronic medical record analysis of indications for DOAC concentration measurements by anti-factor Xa activity assay at a single academic medical center from July 2015 through April 2020.

Results and conclusions

Ninety-one DOAC concentration measurements were made in 69 patients: 28 received apixaban and 41 received rivaroxaban. The most frequent indication for concentration measurement was drug exposure assessment (38/69; 55%) in patients with potentially altered pharmacokinetics (altered absorption or clearance), recurrent thromboembolic events, or possible medication nonadherence. Fourteen of 69 patients had repeated measurements during preoperative evaluation before emergent surgery; one-third of those with detectable levels upon presentation had repeated measurements until concentrations were undetectable. Levels were undetectable in 4 of 4 patients scheduled for elective surgery. Eleven of 69 patients had DOAC measurements in the setting of major bleeding; 5 of these 11 received a specific DOAC reversal agent. While most of the observed indications appear in clinical guidelines, altered absorption does not. Overall, clinicians are requesting DOAC concentration measurements to evaluate drug exposure in patients with conditions that might alter the absorption or clearance of the DOAC, to evaluate surgical bleeding risk, and in the setting of major bleeding.

Fistula-related stigma is common. The absence of a unifying conceptual framework prevents a nuanced understanding of the nature of fistula-related stigma, comparison across contexts and the ability to contrast with other stigmas. It also hinders intervention development. We conducted in-depth interviews or focus groups with 60 women who had undergone fistula surgery 6-24 months prior at Mulago Hospital in Kampala, Uganda in 2014. Transcripts were analysed for experiences and consequences of enacted, anticipated and internalised stigma. Narratives revealed experiences with enacted stigma, including gossip, verbal abuse and social exclusion. Women also anticipated and feared stigma in the future. Internalised stigma reports revealed shame and low self-esteem: self-worth reduction, feeling disgraced and envisioning no future. Consequences included social isolation, changes to normal activities, non-disclosure and poor mental health. Refining stigma theory to specific conditions has resulted in a more nuanced understanding of stigma dimensions, manifestations, mechanisms and consequences, permitting comparison across contexts and populations and the development of stigma-reduction interventions. These lessons should be applied to fistula, acknowledging unique features: concealability, the potential for treatment, lack of community awareness and the social consequences of stillbirth. Reducing fistula-related stigma requires timely surgery and supportive care, stigma-reduction interventions and addressing the complex societal structures that perpetuate fistula.

Objectives

Lower than recommended doses of direct-acting oral anticoagulants are often prescribed to older adults with nonvalvular atrial fibrillation (NVAF). Our goal was to determine the consequences of lower than recommended dosing on plasma apixaban concentrations during the clinical care of older adults with NVAF.

Design

Convenience sample of patients receiving anticoagulation during 2017.

Setting

Academic medical center.

Participants

Stable adults older than 65 years with NVAF receiving apixaban on a chronic basis.

Measurements

Patient age, weight, creatinine, co-medications, and apixaban concentrations.

Results

A total of 110 older adults with NVAF (mean age = 80.4 y; range = 66-100 y with 45% women) were studied. Overall, 48 patients received recommended dosing of 5 mg twice/day, and 42 received lower than recommended dosing. One patient in each category had concentrations below the expected 5% to 95% range at time of peak concentrations. Differences in proportion of apixaban concentrations within or outside expected ranges were not significant between patients receiving lower than recommended doses and those dosed as recommended at 5 mg twice/day (P = .35). However, in patients dosed as recommended with 5 mg twice/day, four had concentrations above the 5% to 95% range for peak levels expected at 3 to 4 hours after dosing; in two, this occurred around the midpoint of the dosing interval. Twenty patients received 2.5 mg twice/day as recommended. One-third had apixaban concentrations higher than expected peak concentrations compared with the clinical trials, and more than two-thirds had levels above the reported median for peak concentrations.

Conclusions

Apixaban concentrations in older adults with NVAF seen clinically were higher than expected based on clinical trial data. The findings raise questions about the optimal dosing of apixaban in older adults with NVAF encountered outside of clinical trials and suggest a role for the monitoring of apixaban concentrations during care of patients that differ from those in randomized trials or when considering dosing outside of published guidelines. J Am Geriatr Soc 67:1902-1906, 2019.