Effectiveness and safety of non-vitamin K antagonist oral anticoagulants versus warfarin among nonvalvular atrial fibrillation patients with prior bleeding events

Background

Patients with non-valvular atrial fibrillation (NVAF) use oral anticoagulants such as warfarin or non-vitamin K antagonist oral anticoagulants (NOACs) for the prevention of stroke. However, the effectiveness and safety of warfarin and NOACs can be influenced by pre-existing patient comorbidities, such as a history of bleeding, and limited evidence are available to inform the choice of the most appropriate anticoagulant treatment for NVAF patients with bleeding history.

Purpose

This study used five United States insurance claims databases to evaluate the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) among NVAF patients with prior bleeding events who were prescribed NOACs versus warfarin.

Methods

This retrospective observational study used data from 5 databases (CMS Medicare and four commercial databases, covering >180 million beneficiaries) to select adult NVAF patients who were treated with apixaban, dabigatran, rivaroxaban, or warfarin (01JAN2013–30JUN2019). Patients were required to have a prior bleeding event, defined as a hospitalization with a diagnosis for intracranial hemorrhage (ICH), gastrointestinal (GI) bleeding or bleeding at other key sites prior to or during the index treatment episode. In each database, three 1:1 NOAC-warfarin propensity-score-matched (PSM) cohorts were created before pooling the results. Outcome measures were time to first stroke/SE, (ischemic stroke, hemorrhagic stroke, and SE), and time to first MB (gastrointestinal bleeding, intracranial hemorrhage, and MB at other key sites), and were measured from the index treatment episode to treatment discontinuation or switch, death, health plan disenrollment, or end of study period. Hazard ratios of S/SE and MB were calculated using Cox proportional hazards models.

Results

Among the eligible NVAF population, 8.2% of patients had a prior bleeding event (ICH: 12.3%; GI: 60.7%; Other: 27.0%). After PSM, a total of 43,092 apixaban-warfarin, 11,295 dabigatran-warfarin, and 32,723 rivaroxaban-warfarin patient pairs with prior bleeding were selected with a mean follow-up of 8–9 months. Apixaban and rivaroxaban were associated with a lower risk of S/SE, and dabigatran was associated with a similar risk of S/SE when compared to warfarin. Apixaban and dabigatran were associated with a lower risk of MB, and rivaroxaban was associated with a similar risk of MB, compared to warfarin (Figure).

Conclusion

Among NVAF patients with prior bleeding events, NOACs were associated with varying risks of S/SE and MB compared to warfarin. These results can help inform healthcare providers concerning the impact of OAC treatment in NVAF patients with history of bleeding.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer, Inc.

Time at home among nonvalvular atrial fibrillation patients treated with non-vitamin K antagonist oral anticoagulants: an ARISTOPHANES analysis

Background

Patient-centered outcomes, such as home time, are becoming increasingly important quality-of-life measures. There are limited data on the impact of oral anticoagulants (OACs) on home time among patients with non-valvular atrial fibrillation.

Purpose

This analysis, based on the previously published ARISTOPHANES study, used five US insurance claims databases (CMS Medicare and four commercial databases) to compare home time among NVAF patients who were prescribed non-vitamin K antagonist OACs (NOACs).

Methods

Adult NVAF patients who were newly prescribed apixaban, dabigatran, or rivaroxaban (01JAN2013–30SEP2015) were selected. Time at home was calculated as the number of days from the index date (NOAC prescription) without any of the following: an inpatient, skilled nursing facility (SNF) or nursing facility, hospice, or inpatient rehabilitation facility admission. Time at home and without external AF-related care was defined as days from index date without any events from the home time endpoint or any days with a claim for bleeding, stroke/systemic embolism (S/SE), AF, or an INR test. Time at home and without external AF-related care were measured during the 180 days of follow-up; patients were required to have been alive and have 180 days of follow-up post index. In each database, three 1:1 NOAC-NOAC propensity-score-matched (PSM) cohorts were created before combining the databases. For each NOAC-NOAC matched cohort, Poisson regression was conducted to compare time at home and time at home without external AF-related care.

Results

After PSM, 37,314 apixaban-dabigatran, 107,236 apixaban-rivaroxaban, and 37,693 rivaroxaban-dabigatran patient pairs were created of which 37–44% had 180 days of follow-up available. Across the NOAC cohorts, approximately 21–25% of patients had an admission to a hospital, SNF, nursing facility, rehabilitation center, or hospice during the 180-day follow-up. The time at home was generally consistent between the NOAC cohorts (177 days); however, apixaban patients had 0.5 more days at home compared to rivaroxaban patients. Across all NOAC cohorts, 7–8% had a claim for a S/SE, 11–15% had a claim for bleeding, and 15–22% had an INR test, while 87–89% of all patients had an AF-claim during the 180-day follow-up. Patients prescribed apixaban had 1 more day at home without external AF-related care compared to dabigatran, and 1.5 more days at home without external AF-related care compared to rivaroxaban. Dabigatran had <1 more day at home without external AF-related care compared to rivaroxaban.

Conclusion

Among NVAF patients treated with NOACs, there were small differences in the time at home and time at home without external AF-related care during the first 6 months of NOAC treatment. As NVAF is a chronic condition, it is important to understand the impact of NOAC treatment on these patient-centered outcomes.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer Inc.

Effectiveness and safety of apixaban vs warfarin among older venous thromboembolism patients: a subgroup analysis of age

Background

Venous thromboembolism (VTE) is the third most common cardiovascular condition in adult patients. Older patients are at an increased risk of VTE. However, they have been underrepresented in clinical trials and evidence on the safety and effectiveness of anticoagulants in older VTE patients, especially very elderly patients (≥80 years), is sparse.

Purpose

To evaluate the risk of recurrent VTE, major bleeding (MB), and clinically relevant non-major (CRNM) bleeding among older VTE patients initiating apixaban or warfarin according to two age sub-groups: 65–79 and ≥80 years.

Methods

Older VTE patients (aged ≥65 years) who initiated apixaban or warfarin were identified from the CMS Medicare database (September 2014–December 2017). To balance the characteristics between apixaban and warfarin patients, stabilized inverse probability treatment weighting (IPTW) was conducted. Post IPTW, a subgroup interaction analysis was conducted to evaluate if there was any difference in treatment effects between the two age subgroups (65–79 vs. ≥80) on recurrent VTE, MB, and CRNM bleeding. Cox proportional hazard models were used to conduct the interaction analysis, and the statistical significance of the interaction was set to p-value <0.10.

Results

A total of 22,135 apixaban and 45,840 warfarin patients with VTE aged ≥65 years were eligible for analysis. Post IPTW, patient characteristics were balanced between the apixaban and warfarin treatment cohorts. Apixaban patients had significantly lower risk of recurrent VTE, MB, and CRNM bleeding compared to warfarin patients (Figure). 42,551 (62.6%) were aged 65–79 years and 25,424 (37.4%) were aged ≥80 years. Among apixaban or warfarin patients, those aged 65–79 years had lower Charlson comorbidity index scores (mean 2.7 vs 3.2) and were less likely to have a diagnosis of anemia (34.7–34.9% vs 42.3–42.5%), cerebrovascular disease (14.7–15.7% vs 20.3–20.5%), or dementia (5.0–6.9% vs 20.4–24.6%) compared to patients aged ≥80 years. Across both age subgroups, incidence rates of recurrent VTE, MB and CRNM bleeding were lower for apixaban vs. warfarin. No significant interaction was observed between the treatment and age on recurrent VTE and MB (Figure). There was a significant interaction between treatment and age on CRNM bleeding. Apixaban trended towards a lower risk of CRNM bleeding across both age groups but the treatment effect on CRNM bleeding was larger for patients aged 65–79 years.

Conclusion

The treatment effects of apixaban vs. warfarin on recurrent VTE and MB were consistently observed across both older age groups in this analysis. More studies are needed to evaluate management of VTE in an older and especially the very elderly population.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer Inc.

Effectiveness and safety of apixaban vs warfarin among older venous thromboembolism patients stratified by race

Background

Race has been identified as a risk factor for venous thromboembolism (VTE), with Black individuals having a higher risk of VTE compared to Caucasians. Black patients have been underrepresented in clinical trials evaluating anticoagulants for VTE. There has been limited evidence about the effects of anticoagulants for Black patients with VTE in routine clinical practice.

Purpose

To evaluate the risk of recurrent VTE, major bleeding (MB), and clinically relevant non-major (CRNM) bleeding among VTE patients initiating apixaban or warfarin stratified by race.

Methods

Older VTE patients (≥65 years) who initiated apixaban or warfarin were selected from the CMS Medicare database (September 2014–December 2017). Stabilized inverse probability treatment weighting (IPTW) was used to balance the differences between apixaban and warfarin cohorts. After IPTW, subgroup interaction analysis was conducted to evaluate if treatment effects were different between Black and White patients in the Medicare population. Due to small sample size, other races were not included in the interaction analysis. Cox proportional hazard models were used to evaluate if there was significant interaction (p<0.10) between treatment and race on recurrent VTE, MB, or CRNM bleeding.

Results

A total of 22,135 apixaban and 45,840 warfarin patients with VTE were included in the analysis. Post-IPTW, patient characteristics were balanced between apixaban and warfarin treatment cohorts. Apixaban patients had significantly lower risk of recurrent VTE, MB, and CRNM bleeding compared to warfarin patients (Figure). When stratified by race, 57,008 (83.9%) were White, 7,832 (11.5%) Black, and 3,135 (4.6%) other races. For both treatment cohorts, age was similar between Black (77.0–77.2 years) and White (77.4–77.5 years) patients. However, Black patients were more likely to have an inpatient VTE event (77.3–77.8% vs. 63.1–63.3%), a provoked VTE event (78.6–79.5% vs 69.4–69.6%), and a higher comorbidity index score (mean 4.1 vs. 2.7) compared to White patients with VTE. The incidence rates per 100 person-years of recurrent VTE (2.0–3.3 vs 1.4–2.2) and MB (7.4–10.1 vs 3.5–5.3) were also numerically higher for Black patients compared to White patients. Across both race groups, apixaban patients had a lower incidence rate of recurrent VTE, MB and CRNM bleeding compared to warfarin patients. No significant interaction was observed between treatment and race for recurrent VTE, MB, or CRNM bleeding (Figure). The findings within each race group were consistent with those of the overall VTE population.

Conclusion

Among older VTE patients, disparities were observed in VTE characteristics and clinical outcomes between Black and White patients. Across both race groups, apixaban had lower risk of recurrent VTE, MB, and CRNM bleeding compared to warfarin patients. Further studies are needed to identify optimal management strategies for Black patients with VTE.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Pfizer IncBristol-Myers Squibb Company

Time at home among nonvalvular atrial fibrillation patients treated with non-vitamin K antagonist oral anticoagulants versus warfarin

Background

Clinical trials and real-world database studies have shown the benefits of non-vitamin K antagonist oral anticoagulants (NOACs) compared to warfarin; however, measures of functional outcomes are critical in evaluating a patient's quality of life. Previous measures of time spent out of hospital in a home setting and time spent receiving disease-related care among non-valvular atrial fibrillation (NVAF) patients are lacking in the current literature.

Purpose

This analysis was based on the previously published ARISTOPHANES study, and used multiple data sources to evaluate the amount of time spent at a patient's home among NVAF patients who were prescribed NOACs versus warfarin.

Methods

This retrospective observational study used US data from CMS Medicare and four commercial databases to select adult NVAF patients who initiated apixaban, dabigatran, rivaroxaban, or warfarin (01JAN2013–30SEP2015). Time at home and time at home without external AF-related care were measured during the 180 days after the index date (OAC prescription). Time at home was defined as days from index date without any of the following: an inpatient, skilled nursing facility or nursing facility, hospice, or inpatient rehabilitation facility admission. Time at home and without external AF-related care was defined as days away from home and days with a claim for bleeding, stroke/systemic embolism, AF, or an INR test. Each day a claim was observed was counted as one day. In each database, three 1:1 NOAC-warfarin propensity-score-matched (PSM) cohorts were created before pooling the results. After PSM, a subgroup of patients who were alive and had ≥180 days of follow-up was created. Poisson regression was conducted in each NOAC-warfarin matched cohort to compare time at home and time at home without external AF-related care.

Results

After matching, a total of 100,977 apixaban-warfarin, 36,990 dabigatran-warfarin, and 125,068 rivaroxaban-warfarin patient pairs were selected. Of those patients, 38–46% had 180 days of follow-up available. Across treatment cohorts, approximately 75% of patients were at home for the 180-day follow-up. Apixaban, dabigatran, and rivaroxaban patients had 1.3, 0.9, and 0.8 more days at home, respectively, compared to warfarin patients. Patients treated with apixaban had 13.4 more days at home without AF-related care compared to warfarin, while dabigatran and rivaroxaban had 11.6 and 11.7 more days at home without AF-related care compared to warfarin. A greater proportion of warfarin patients than NOAC patients had an INR test (81–82% vs 14–21%), and days with INR testing were the main driver for external AF-related care for warfarin patients.

Conclusion

Among NVAF patients treated with OACs, NOACs were associated with a longer time at home and time at home without external AF-related care compared to warfarin. These results can help inform healthcare providers and patients regarding the impact of NOAC treatment in NVAF patients.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer Inc.

Effectiveness and safety of apixaban vs warfarin among venous thromboembolism patients using five US databases: a subgroup analysis of chronic liver disease

Background

Venous thromboembolism (VTE) is a serious disease in the United States affecting approximately 1 in 1000 patients each year. Patients with chronic liver disease (CLD) are at an increased risk of VTE and major bleeding (MB). Currently, insufficient clinical and real-world evidence exists on the efficacy/effectiveness and safety of apixaban or warfarin in VTE patients with CLD.

Purpose

To evaluate the risk of recurrent VTE, MB, and clinically relevant non-major (CRNM) bleeding among VTE patients initiating apixaban or warfarin stratified by CLD status.

Methods

VTE patients ≥18 years of age (≥65 years for Medicare) initiating apixaban or warfarin were identified from CMS Medicare and four commercial claims databases. To balance the characteristics between apixaban and warfarin patients, stabilized inverse probability treatment weighting (IPTW) was conducted. Post-IPTW, subgroup interaction analysis was conducted to evaluate whether treatment effects of apixaban vs. warfarin were consistent across patients with and without a diagnosis of CLD. Cox proportional hazard models were used to evaluate the interaction of the treatment (apixaban vs. warfarin) and CLD on recurrent VTE, MB, and CRNM bleeding. The statistical significance of the interaction was set to p-value <0.10.

Results

A total of 60,786 apixaban and 94,333 warfarin patients with VTE were eligible for analysis. Post-IPTW, all patient characteristics were balanced between the apixaban and warfarin treatment cohorts. Apixaban treated patients had significantly lower risk of recurrent VTE, MB, and CRNM bleeding compared to warfarin patients (Figure). In the IPTW weighted population, 4,766 (7.8%) apixaban patients and 6,320 (6.7%) warfarin patients had a diagnosis of CLD. For the apixaban or warfarin patients, those with a diagnosis of CLD were generally younger (mean 64.0–65.2 vs 66.9 years), had higher Charlson comorbidity index scores (mean 3.8–3.9 vs 2.1) and were more likely to have an inpatient VTE event (67.8–69.5% vs 53.0–53.2%) or provoked VTE events (66.2–67.8% vs 55.4–55.5%) compared to patients without a diagnosis of CLD. The incidence rate of recurrent VTE, MB, and CRNM bleeding was higher among VTE patients with CLD than without CLD and was also higher for patients treated with warfarin compared to those treated with apixaban regardless of CLD status (Figure). There were no significant interactions observed between treatment and CLD status for recurrent VTE, MB or CRNM (Figure).

Conclusion

Treatment with apixaban had a lower risk of recurrent VTE, MB, and CRNM bleeding compared to treatment with warfarin. The benefits of apixaban were consistently observed among subgroups of VTE patients with and without CLD. Additional studies are needed to evaluate VTE patients with CLD.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer, Inc.

Effectiveness and safety of non-vitamin K antagonist oral anticoagulants among nonvalvular atrial fibrillation patients with prior bleeding events

Background

Among non-valvular atrial fibrillation (NVAF) patients with a history of bleeding, there is a reluctance to use oral anticoagulants (OACs) due to concerns about the risk of bleeding associated with OACs. However, lack of OAC treatments for NVAF patients is associated with a higher risk of stroke and mortality. Non-vitamin K antagonist OAC (NOACs) have been approved for the prevention of stroke in NVAF patients. There are limited data comparing the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) between patients prescribed NOACs and with a history of bleeding.

Purpose

This study used multiple United States data sources to evaluate the risk of S/SE and MB among NVAF patients with prior bleeding events who were prescribed NOACs.

Methods

This retrospective observational study used data from CMS Medicare and four commercial databases–covering >180 million beneficiaries. The study selected adult NVAF patients who were prescribed apixaban, dabigatran, or rivaroxaban (01JAN2013–30JUN2019) and had a prior bleeding event which was defined as a hospitalization with a bleeding diagnosis (intracranial hemorrhage [ICH], gastrointestinal [GI] bleeding, or other bleeding sites) prior to or during the index treatment episode. After 1:1 propensity-score-matched (PSM) in each database between NOACs (apixaban-dabigatran, apixaban-rivaroxaban, and dabigatran-rivaroxaban), the resulting patient records were pooled. S/SE and MB (identified by inpatient claims) were captured during the follow-up period, which was defined as the time between the day after the index treatment date and treatment discontinuation or switch, death, end of study period, or end of medical and pharmacy enrollment. Hazard ratios of S/SE and MB were calculated using Cox proportional hazards models.

Results

Of the overall NVAF population treated with NOACs, 6.2% had a prior bleeding event (ICH: 13.5%; GI: 61.8%; Other: 24.6%). After PSM, a total of 11,106 apixaban-dabigatran, 30,665 apixaban-rivaroxaban, and 11,148 dabigatran-rivaroxaban pairs were matched. Apixaban was associated with a lower risk of S/SE compared to dabigatran and rivaroxaban, and dabigatran was associated with a similar risk of S/SE compared to rivaroxaban. Apixaban was associated with a lower risk of MB compared to dabigatran and rivaroxaban, and dabigatran was associated with a lower risk of MB compared to rivaroxaban (Figure).

Conclusions

In this subgroup of NVAF patients with a history of bleeding, apixaban was associated with a lower risk of S/SE and MB compared to dabigatran and rivaroxaban. Dabigatran was associated with a lower risk of MB compared to rivaroxaban. These results are informative for understanding the impact of NOAC treatment in NVAF patients with prior bleeding events.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Bristol-Myers Squibb Company and Pfizer, Inc.

The non-steroidal anti-inflammatory drug carprofen negatively impacts new bone formation and antibiotic efficacy in a rat model of orthopaedic-device-related infection

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used for pain management during recovery from orthopaedic surgery. NSAID use is associated with increased risk of bone healing complications but it is currently unknown whether NSAIDs increase the risk of developing an orthopaedic-device-related infection (ODRI) and/or affects its response to antibiotic therapy. The present study aimed to determine if administration of the NSAID carprofen [a preferential cyclooxygenase-2 (COX-2) inhibitor] negatively affected Staphylococcus epidermidis (S. epidermidis) bone infection, or its subsequent treatment with antibiotics, in a rodent ODRI model. Sterile or S. epidermidis-contaminated screws (~ 1.5 x 10⁶ CFU) were implanted into the proximal tibia of skeletally mature female Wistar rats, in the absence or presence of daily carprofen administration. A subset of infected animals received antibiotics (rifampicin plus cefazolin) from day 7 to 21, to determine if carprofen affected antibiotic efficacy. Bone changes were monitored using in vivo µCT scanning and histological analysis. The risk of developing an infection with carprofen administration was assessed in separate animals at day 9 using a screw contaminated with 10² CFU S. epidermidis. Quantitative bacteriological analysis assessed bacterial load at euthanasia. In the 28-day antibiotic treatment study, carprofen reduced osteolysis but markedly diminished reparative bone formation, although total bacterial load was not affected at euthanasia. Antibiotic efficacy was negatively affected by carprofen (carprofen: 8/8 infected; control: 2/9 infected). Finally, carprofen increased bacterial load and diminished bone formation following reduced S. epidermidis inoculum (10² CFU) at day 9. This study suggests that NSAIDs with COX-2 selectivity reduce antibiotic efficacy and diminish reparative responses to S. epidermidis ODRI.

P4794Comparative effectiveness and safety of non-VKA oral anticoagulants versus warfarin in non-valvular atrial fibrillation patients with differential treatment duration: an ARISTOPHANES study analysis

Background

The ARISTOPHANES (Anticoagulants for Reduction In STroke: Observational Pooled analysis on Health outcomes ANd Experience of patientS) study showed that non-vitamin K antagonist oral anticoagulants (NOACs) were associated with lower risks of stroke/systemic embolism (S/SE) and variable comparative risks of major bleeding (MB) versus warfarin.

Purpose

To assess long-term use of non-VKA oral anticoagulants (NOACs) vs. warfarin in

ARISTOPHANES by evaluating the risk of S/SE and MB among non-valvular atrial fibrillation (NVAF) patients by duration of treatment (<1 and ≥1 year).

Methods

In the ARISTOPHANES study, NVAF patients initiating apixaban, dabigatran, rivaroxaban, or warfarin from 01/01/2013–09/30/2015 were identified from the CMS Medicare data and four US commercial claims databases, covering >180 million beneficiaries annually (∼56% of US population). After 1:1 propensity score matching (PSM) in each database between NOACs and warfarin (apixaban-warfarin, dabigatran-warfarin, and rivaroxaban-warfarin), the resulting patient records were pooled. Treatment duration was defined as time between the day after the treatment index date and discontinuation (30 days after a 30-day gap in the prescription), treatment switch, death, end of study period, or end of continuous medical and pharmacy enrollment, whichever occurred first. Matched patients with observed treatment duration <1 or ≥1 year were separately examined. Cox models were used to estimate hazard ratios of S/SE and MB (identified by inpatient claims) during observed treatment duration.

Results

The mean treatment duration for patients with shorter (<1 year) vs longer (≥1 year) duration was 4–5 months vs 18–21 months across the three matched cohorts. All the matched baseline variables remained balanced. The incidence rates of S/SE and MB and the proportion of patients with treatment discontinuation were higher in patients with shorter treatment duration. Regardless of treatment duration, apixaban patients had a lower risk of S/SE and MB versus warfarin; dabigatran patients had a lower risk of MB versus warfarin; and rivaroxaban patients had a lower risk of S/SE versus warfarin. Compared to warfarin patients, dabigatran patients with treatment duration <1 year had a similar risk of S/SE, while those with treatment duration ≥1 year had lower S/SE risk; rivaroxaban patients with treatment duration <1 year had a higher risk of MB, while those with treatment duration ≥1 year had similar MB risk.

Conclusions

Among NVAF patients with duration of treatment <1 and ≥1 year in the ARISTOPHANES study, apixaban and rivaroxaban were associated with lower risk of S/SE, while apixaban and dabigatran were associated with lower risk of MB, compared to warfarin. These findings indicate varying long-term effectiveness and safety outcomes between NOACs and warfarin.

Acknowledgement/Funding

This study was funded by Bristol-Myers Squibb and Pfizer Inc.

P4768Comparative effectiveness and safety between non-VKA oral anticoagulants in non-valvular atrial fibrillation patients with differential duration of treatment: an analysis of the ARISTOPHANES study

Background

The ARISTOPHANES (Anticoagulants for Reduction In STroke: Observational Pooled analysis on Health outcomes ANd Experience of patientS) study showed that apixaban was associated with lower risks of stroke/systemic embolism (S/SE) and major bleeding (MB) versus dabigatran and rivaroxaban; dabigatran was associated with similar risk of S/SE and lower risk of MB compared to rivaroxaban.

Purpose

To assess long-term use of non-VKA oral anticoagulants (NOACs) in ARISTOPHANES by evaluating the risk of S/SE and MB among non-valvular atrial fibrillation (NVAF) patients receiving different NOACs by duration of treatment (<1 and ≥1 year).

Methods

In the ARISTOPHANES study, NVAF patients initiating apixaban, dabigatran, and rivaroxaban from 01/01/2013–09/30/2015 were identified from the CMS Medicare data and four US commercial claims databases, covering >180 million beneficiaries annually (∼56% of US population). After 1:1 propensity score matching (PSM) in each database between NOACs (apixaban-dabigatran, apixaban-dabigatran, and dabigatran-rivaroxaban), the resulting patient records were pooled. Treatment duration was defined as time between the day after the index treatment date and discontinuation (defined using a 30-day gap in the prescription), treatment switch, death, end of study period, or end of continuous medical and pharmacy enrollment, whichever occurred first. Matched patients with observed treatment duration <1 or ≥1 year were separately examined. Cox models were used to estimate hazard ratios of S/SE and MB (identified by inpatient claims) during observed treatment duration. S/SE included ischemic stroke, hemorrhagic stroke, and SE; MB included gastrointestinal (GI) bleeding, intracranial hemorrhage (ICH), and other MB.

Results

The mean treatment duration for patients with shorter (<1 year) vs longer (≥1 year) duration was ∼4 months vs 18–21 months across the three matched cohorts. All the matched baseline variables remained balanced. The incidence rates of S/SE and MB and the proportion of patients with treatment discontinuation were higher in patients with shorter treatment duration. Regardless of treatment duration, apixaban and dabigatran had a lower risk of MB versus rivaroxaban; and dabigatran had a similar risk of S/SE versus rivaroxaban. Compared to dabigatran patients, apixaban patients with treatment duration <1 year had a lower risk of S/SE and MB, while those with treatment duration ≥1 year had similar S/SE and MB risk. Compared to rivaroxaban patients, apixaban patients with treatment duration <1 year had a lower risk of S/SE, while those with treatment duration ≥1 year had similar S/SE risk.

Conclusions

Across NVAF patients with duration of treatment <1 and ≥1 year in the ARISTOPHANES study, both apixaban and dabigatran were associated with a lower risk of MB compared to rivaroxaban. These findings indicate varying long-term safety outcomes among different NOACs.

Acknowledgement/Funding

This study was funded by Bristol-Myers Squibb and Pfizer Inc.

P5589Patterns of extended apixaban treatment for unprovoked venous thromboembolism in routine clinical practice

Background

Current CHEST guidelines recommend extended anticoagulation therapy without a scheduled stop in patients with unprovoked VTE and low bleeding risk following initial anticoagulation treatment of 3 months. AMPLIFY-EXT suggests that extended treatment with apixaban beyond 6 months reduces the risk of recurrent VTE without increasing major bleeding rates. This study evaluated patterns of extended apixaban treatment among unprovoked VTE patients.

Methods

Utilizing 4 US commercial claims databases, this retrospective study assessed unprovoked VTE patients (VTE events that were not preceded by a provoked factor or event) who initiated apixaban within 30 days from the VTE event (01SEPT2014–31MAR2018). Patients were required to have ≥6 months continuous apixaban treatment (without a gap of >30 days). Characteristics of patients treated beyond 6 months and those who discontinued at 6 months were evaluated respectively. An additional analysis was conducted to assess proportion with apixaban treatment for ≥3 months.

Results

Among unprovoked VTE patients, 60.8% and 34.6% had apixaban treatment for ≥3 and ≥6 months, respectively. Of those treated for ≥6 months (3,015 after applying additional selection criteria), 75.6% continued treatment beyond 6 months and 24.4% discontinued at 6 months. Younger age and having thrombophilia were associated with a higher likelihood of treatment beyond 6 months (Table). Among patients with treatment beyond 6 months, 7.5% of patients switched from apixaban 5mg to 2.5mg, 36.5% discontinued therapy, and 1.1% switched to another oral anticoagulant (Figure).

Baseline characteristics Variables Discontinued at 6 months Continued treatment beyond 6 months P-value N=735 N=2,280 Age, Mean (SD) 63.0 (15.2) 61.7 (14.3) 0.037 Gender – Female, n (%) 307 (41.8%) 892 (39.1%) 0.203 Setting of Unprovoked VTE Event – Ambulatory, n (%) 592 (80.5%) 1,834 (80.4%) 0.950 VTE Diagnosis – DVT Only, n (%) 494 (67.2%) 1,498 (65.7%) 0.452 Deyo-Charlson Comorbidity Index, Mean (SD) 1.3 (1.9) 1.3 (1.8) 0.305 Thrombophilia, n (%) 54 (7.3%) 296 (13.0%) <0.001 Coagulation Defects, n (%) 38 (5.2%) 153 (6.7%) 0.136 Baseline Bleed, n (%) 77 (10.5%) 210 (9.2%) 0.309

KM curve after 6 months of apixaban use

Conclusion

Among unprovoked VTE patients treated with apixaban, a large proportion did not receive ≥3 months of treatment. Although AMPLIFY-EXT showed beneficial effects of extended treatment, the percentage of patients with ≥6 months of treatment was low. Thrombophilia was the only meaningful predictor of treatment beyond 6 months.

Acknowledgement/Funding

This study was funded by Bristol-Myers Squibb and Pfizer Inc

Examining the treatment gap and risk of subsequent fractures among females with a fragility fracture in the US Medicare population

Our aim was to evaluate the gap in osteoporosis treatment and the impact of osteoporosis treatment on subsequent fragility fractures. We found osteoporosis medication use lowered risk of subsequent fractures by 21% and that black race, higher CCI scores, dementia, and kidney diseases reduced the likelihood of osteoporosis medication use.

INTRODUCTION

The goal of this study was to evaluate the predictors of osteoporosis medication use and compare the risk of fragility fractures within 1 year of a fragility fracture between osteoporosis treated and untreated women.

METHODS

We conducted a retrospective, observational cohort study using the national Medicare database. Elderly women (≥65 years) who were hospitalized or had an outpatient/ER service for fragility fracture between January 1, 2011 and December 31, 2011 were included. The outcomes of interest were the correlates of and time-to-osteoporosis medication use and risk of a subsequent fracture within 12 months for treated and untreated women. Cox regression was used to evaluate the predictors of treatment use and the risk of fracture based on treatment status.

RESULTS

Women (28,722) (27.7%) were treated with osteoporosis medication within 12 months of index fracture, and 74,979 (72.2%) were untreated. A number of patient characteristics were associated with a reduced likelihood of osteoporosis medication use, including black race, higher Charlson comorbidity index scores, presence of dementia, and kidney diseases in the baseline. The predictor most strongly and positively associated with osteoporosis medication use after fracture was osteoporosis medication use before fragility fracture (HR = 7.87; 95% CI 7.67-8.07). After adjusting for baseline characteristics, osteoporosis medication use lowered the risk of subsequent fractures by 21% (HR = 0.79, 95% CI 0.75-0.83) over 12 months compared to women without treatment.

CONCLUSIONS

Demographics and clinical characteristics were strong predictors of osteoporosis medication use. In the US Medicare population, osteoporosis treatment significantly reduced the risk of fragility fractures.

Ventral herniorrhaphy: experience with two different biosynthetic mesh materials, Surgisis and Alloderm

OBJECTIVE

The aim of this study was to compare the efficacy and the complications associated with the use of two new bioactive meshes, Surgisis Gold 8-ply mesh, a product obtained by the processing of porcine small intestine sub-mucosa (Cook Surgical, Bloomington, IN, USA), and Alloderm, processed cadaveric human acellular dermis (Life Cell Corporation, Branchburg, NJ, USA), for ventral herniorrhaphy.

BACKGROUND

Ventral hernia repair in potentially contaminated or potentially infected fields limit the use of synthetic mesh products. In this scenario, biosynthetic mesh products that are absorbed and/or replaced with the body's own tissue reduce the incidence of post-operative chronic wound complications (Franklin et al. in Hernia 8(3):186-189, 2004; Franklin et al. in Hernia 6(4):171-174, 2002; Hirsch in J Am Coll Surg 198(2):324-328, 2004; Holton et al. in J Long Term Eff Med Implants 15(5):547-558, 2005; Buinewicz and Rosen in Ann Plast Surg 52(2):188-194, 2004). Rapid revascularization, repopulation, and remodeling of the matrix occur on contact with the patient's own tissue. Only limited, and mostly preliminary data, is available on the use of these types of mesh and concerning the potential complications associated with the use of these types of meshes. We publish our experience with the use of these mesh products, along with their associated complications. Furthermore, we have also provided suggestions for improvements in the mesh designs.

METHODS

Between June 2002 and March 2005, 74 patients underwent ventral hernia repair using biosynthetic or natural tissue mesh. The first 41 procedures were performed using Surgisis Gold 8-ply mesh formed from porcine small intestine sub-mucosa, and the remaining 33 patients had ventral hernia repair with Alloderm. The patients had their first follow-up 7-10 days after discharge from the hospital. They were again seen at 6 weeks, or, if needed, earlier, and, thereafter, as needed. Patients who reported any complications to the office were followed up immediately within 1-2 days. Any signs of wound infection, diastasis, hernia recurrence, changes in bowel habits, and seroma formation were evaluated.

RESULTS

Non-perforated Surgisis mesh resulted in significant seroma formation in 10/11 patients. The seroma complication was reduced, but not eliminated, with the use of the perforated Surgisis mesh (3/30 patients). Explanted material revealed separated layers of un-incorporated middle layers of the 8-ply Surgisis mesh. Three of the patients had the mesh placed in a contaminated field with no resultant sequela, and there were no hernia recurrences. Patients also had a significant degree of discomfort and pain during the immediate post-operative period. The use of the Alloderm mesh resulted in eight hernia recurrences. Fifteen of the Alloderm patients (15/33) developed a diastasis or bulging at the repair site. Seroma formation was only a problem in two patients.

CONCLUSIONS

Seroma formation was a major problem with the non-perforated Surgisis mesh repair, as was the post-operative pain. On the other hand, post-operative diastasis and hernia recurrence were a major problem with the Alloderm mesh. Further design improvements are required in both forms of these new mesh products. Surgeons should be aware of these potential complications prior to the selection of either of these products and the patient should be informed and educated accordingly.

"Mini-sternotomy" for bilateral pulmonary wedge resections

A mini-sternotomy is described that allows access to both thoracic cavities. This technique offers excellent exposure for lung resections from chest cavities without the invasiveness of a formal thoracotomy.

Four multiple primary malignant neoplasms of the aerodigestive tract

Multiple primary cancers of the head, neck, and upper aerodigestive tract have been documented in patients previously treated for oropharyngeal cancer. There generally is no causal relationship established between the different tumors. Two synchronous or metachronous cancers are common, three are unusual, and four are very unusual. We describe the treatment of a patient with tonsillar and synchronous esophageal and pulmonary cancers followed by a tongue cancer over a 6-year period.