Off-Label Dosing of Direct Oral Anticoagulants Among Inpatients With Atrial Fibrillation in the United States

BACKGROUND

Among patients hospitalized for atrial fibrillation, the frequency of off-label direct oral anticoagulant (DOAC) dosing, associated factors, hospital-level variation, and temporal trends in contemporary practice are unknown.

METHODS

Using the Get With The Guidelines-Atrial Fibrillation registry, patients admitted from January 1, 2014, to March 31, 2020, and discharged on DOACs were stratified according to receipt of underdosing, overdosing, or recommended dosing. Factors associated with off-label dosing (defined as underdosing or overdosing) were identified using logistic regression. Median odds ratio (OR) and time-series analyses were used to assess hospital-level variation and temporal trends, respectively.

RESULTS

Of 22 470 patients (70.1±12.1 years, 48.1% female, 82.5% White) prescribed a DOAC at discharge from hospitalization for atrial fibrillation (66% apixaban, 29% rivaroxaban, and 5% dabigatran), underdosing occurred among 2006 (8.9%), overdosing among 511 (2.3%), and recommended dosing among 19 953 (88.8%). The overall rate of off-label dosing was 11.2%. Patient-related factors associated with off-label dose included age (underdosing: OR, 1.06 per 1-year increase [95% CI, 1.06-1.07]; overdosing: OR, 1.07 per 1-year increase [95% CI, 1.06-1.09]), dialysis dependence (underdosing: OR, 5.50 [95% CI, 3.76-8.05]; overdosing: OR, 5.47 [95% CI, 2.74-10.88]), female sex (overdosing: OR, 0.79 [95% CI, 0.63-0.99]), and weight (overdosing: OR, 0.96 per 1-kg increase [95% CI, 0.95-1.00]). Across hospitals, the adjusted median OR for off-label DOAC dose was 1.45 (95% CI, 1.34-1.65; underdosing: OR, 1.52 [95% CI, 1.39-1.76]; overdosing: OR, 1.32 [95% CI, 1.20-1.84]), indicating significant hospital-level variation. Over the study period, recommended dosing significantly increased over time (81.9%-90.9%; P<0.0001 for trend) with a corresponding decline in underdosing (14.4%-6.6%; P<0.0001 for trend) and overdosing (3.8%-2.5%; P=0.001 for trend).

CONCLUSIONS

Over 1 in 10 patients hospitalized for atrial fibrillation are discharged on an off-label DOAC dose with significant variation across hospitals. While the proportion of patients receiving recommended dosing has significantly improved over time, opportunities to improve DOAC dosing persist.

Changes in Care for Acute Pulmonary Embolism Through A Multidisciplinary Pulmonary Embolism Response Team

BACKGROUND

Optimal management of acute pulmonary embolism requires expertise offered by multiple subspecialties. As such, pulmonary embolism response teams (PERTs) have increased in prevalence, but the institutional consequences of a PERT are unclear.

METHODS

We compared all patients that presented to our institution with an acute pulmonary embolism in the 3 years prior to and 3 years after the formation of our PERT. The primary outcome was in-hospital pulmonary embolism-related mortality before and after the formation of the PERT. Sub-analyses were performed among patients with elevated-risk pulmonary embolism.

RESULTS

Between August 2012 and August 2018, 2042 patients were hospitalized at our institution with acute pulmonary embolism, 884 (41.3%) pre-PERT implementation and 1158 (56.7%) post-PERT implementation, of which 165 (14.2%) were evaluated by the PERT. There was no difference in pulmonary embolism-related mortality between the two time periods (2.6% pre-PERT implementation vs 2.9% post-PERT implementation, P = .89). There was increased risk stratification assessment by measurement of cardiac biomarkers and echocardiograms post-PERT implementation. Overall utilization of advanced therapy was similar between groups (5.4% pre-PERT implementation vs 5.4% post-PERT implementation, P = 1.0), with decreased use of systemic thrombolysis (3.8% pre-PERT implementation vs 2.1% post-PERT implementation, P = 0.02) and increased catheter-directed therapy (1.3% pre-PERT implementation vs 3.3% post-PERT implementation, P = 0.05) post-PERT implementation. Inferior vena cava filter use decreased after PERT implementation (10.7% pre-PERT implementation vs 6.9% post-PERT implementation, P = 0.002). Findings were similar when analyzing elevated-risk patients.

CONCLUSION

Pulmonary embolism response teams may increase risk stratification assessment and alter application of advanced therapies, but a mortality benefit was not identified.

Fluoropyrimidine-Associated Cardiotoxicity: A Retrospective Case-Control Study

BACKGROUND

The fluoropyrimidines, 5-fluorouracil (5-FU) and capecitabine, are commonly used chemotherapeutic agents that have been associated with coronary vasospasm.

METHODS

In this retrospective case-control study, we identified patients at our institution who received 5-FU or capecitabine in 2018. We compared characteristics of patients who experienced cardiotoxicity with controls. We described phenotypes and outcomes of cardiotoxic cases.

RESULTS

We identified 177 patients who received fluoropyrimidines. After adjudication, 4.5% of the cohort met the criteria for cardiovascular toxicity. Coronary artery disease was more common among cases than controls (38% vs. 7%, p < .05). There was also a trend toward increased prevalence of cardiovascular risk factors in cases compared with controls. Most cardiotoxic cases had chest pain, although a minority of cases presented with nonischemic cardiomyopathy.

CONCLUSION

Cardiotoxicity phenotypes associated with fluoropyrimidine use are not limited to coronary vasospasm. Cardiac risk factors and ischemic heart disease were highly prevalent among patients with cardiotoxicity.