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.

Do Wearable Activity Trackers Increase Physical Activity Among Cardiac Rehabilitation Participants? A SYSTEMATIC REVIEW AND META-ANALYSIS

PURPOSE

The objective of this study was to review randomized controlled trials (RCT), which included a wearable activity tracker in an intervention to promote physical activity among cardiac rehabilitation (CR) participants, and to conduct a meta-analysis for the outcomes of step counts and aerobic capacity (V˙o2max).

METHODS

Eight databases were searched for RCTs that included an activity tracker, enrolled adults eligible for CR, and reported outcomes of step count or aerobic capacity. Mean differences were calculated for outcomes in the meta-analyses.

RESULTS

Nineteen RCTs with 2429 participants were included in the systematic review and 10 RCTs with 891 participants were included in the meta-analysis. Meta-analysis of three RCTs using a pedometer or accelerometer demonstrated a significant increase in daily step count compared with controls (n = 211, 2587 steps/d [95% CI, 916-5257]; I2 = 74.6% and P = .002). Meta-analysis of three RCTs using a pedometer or accelerometer intervention demonstrated a significant increase in V˙o2max compared with controls (n = 260, 2.6 mL/min/kg [95% CI, 1.6-3.6]; I2 = 0.0% and P < .0001). Meta-analysis of four RCTs using a heart rate monitor demonstrated a significant increase in V˙o2max compared with controls (n = 420, 1.4 mL/min/kg [95% CI, 0.4-2.3]; I2 = 0.0% and P = .006).

CONCLUSIONS

Use of activity trackers among CR participants was associated with significant increases in daily step count and aerobic capacity when compared with controls. However, study size was small and variability in intervention supports the need for larger trials to assess use of activity trackers in CR.

Impact of patient characteristics and perceived barriers on referral to exercise rehabilitation among patients with pulmonary hypertension in the United States

Exercise rehabilitation is underutilized in patients with pulmonary arterial hypertension despite improving exercise capacity and quality of life. We sought to understand the association between (1) patient characteristics and (2) patient-perceived barriers and referral to exercise rehabilitation. We performed a cross-sectional survey of patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension attending an International PAH meeting. Predictors of referral considered included gender, body mass index, subjective socioeconomic status, insurance type, age, and World Health Organization functional class and perceived barriers assessed using the Cardiac Rehabilitation Barriers Scale. Among 65 participants, those in the lowest subjective socioeconomic status tertile had reduced odds of referral compared to the highest tertile participants (odds ratio 0.22, 95% confidence interval: 0.05–0.98, p = 0.047). Several patient-perceived barriers were associated with reduced odds of referral. For every 1-unit increase in a reported barrier on a five-point Likert scale, odds of referral were reduced by 85% for my doctor did not feel it was necessary; 85% for prefer to take care of my health alone, not in a group; 78% many people with heart and lung problems don’t go, and they are fine; and 78% for I didn’t know about exercise therapy. The lack of perceived need subscale and overall barriers score were associated with a 92% and 77% reduced odds of referral, respectively. These data suggest the need to explore interventions to promote referral among low socioeconomic status patients and address perceived need for the therapy.

Resting Oxygen Consumption and Heart Failure: Importance of Measurement for Determination of Cardiac Output With the Use of the Fick Principle

BACKGROUND

Resting oxygen consumption (VO₂) is often estimated and frequently used to guide therapeutic decisions in symptomatic heart failure (HF) patients. The relationship between resting VO₂ and symptomatic HF and the accuracy of estimations of VO₂ in this population are unknown.

METHODS AND RESULTS

We performed a cross-sectional study of HF patients (n = 691) and healthy control subjects (n = 77). VO₂ was measured with the use of a metabolic cart, and estimated VO₂ was calculated with the use of the Dehmer, LaFarge, and Bergstra formulas and the thermodilution method. The measured and estimated VO₂ were compared and the potential impact of estimations determined. In the multivariable model, resting VO₂ decreased with increasing New York Heart Association (NYHA) functional class in a stepwise fashion (β NYHA functional class IV vs control = -36 mL O₂/min; P < .001). Estimations of VO₂ with the use of derived equations diverged from measured values, particularly for patients with NYHA functional class IV limitations. The percentage difference of measured VO₂ versus estimated VO₂ was >25% in 39% (n = 271), 25% (n = 170), 82% (n = 566), and 39% (n = 271) of HF patients when using the Dehmer, LaFarge, Bergstra, and thermodilution-derived estimations of VO₂ respectively.

CONCLUSIONS

Resting VO₂ decreases with increasing NYHA functional class and is lower than in control subjects. Using estimations of VO₂ to calculate CO may introduce clinically important error.

Naturally occurring mitochondrial-derived peptides are age-dependent regulators of apoptosis, insulin sensitivity, and inflammatory markers

Mitochondria are key players in aging and in the pathogenesis of age-related diseases. Recent mitochondrial transcriptome analyses revealed the existence of multiple small mRNAs transcribed from mitochondrial DNA (mtDNA). Humanin (HN), a peptide encoded in the mtDNA 16S ribosomal RNA region, is a neuroprotective factor. An in silico search revealed six additional peptides in the same region of mtDNA as humanin; we named these peptides small humanin-like peptides (SHLPs). We identified the functional roles for these peptides and the potential mechanisms of action. The SHLPs differed in their ability to regulate cell viability in vitro. We focused on SHLP2 and SHLP3 because they shared similar protective effects with HN. Specifically, they significantly reduced apoptosis and the generation of reactive oxygen species, and improved mitochondrial metabolism in vitro. SHLP2 and SHLP3 also enhanced 3T3-L1 pre-adipocyte differentiation. Systemic hyperinsulinemic-euglycemic clamp studies showed that intracerebrally infused SHLP2 increased glucose uptake and suppressed hepatic glucose production, suggesting that it functions as an insulin sensitizer both peripherally and centrally. Similar to HN, the levels of circulating SHLP2 were found to decrease with age. These results suggest that mitochondria play critical roles in metabolism and survival through the synthesis of mitochondrial peptides, and provide new insights into mitochondrial biology with relevance to aging and human biology.