Risk of major bleeding in patients with non-valvular atrial fibrillation treated with oral anticoagulants: a systematic review of real-world observational studies

OBJECTIVE

To conduct a systematic review of real-world (RWD) studies comparing the risk of major bleeding (MB) among patients with non-valvular atrial fibrillation (NVAF) on direct oral anticoagulants (DOACs) or warfarin.

METHODS

MEDLINE, Embase, NHS-EED, and EconLit were searched for RWD studies published between January 2003 and November 2016 comparing MB risk among DOACs and warfarin. Proceedings of clinical conferences from 2012 to 2016 were reviewed.

RESULTS

A total of 4218 citations were identified, 26 of which met eligibility criteria. Most studies were retrospective analyses of administrative claims databases and patient registries (n = 23 of 26); about half were based in the United States (n = 15). Apixaban showed a significantly lower risk of MB versus warfarin in all eight included studies. MB risk was either significantly lower (n = 9 of 16) or not significantly different (n = 7 of 16) between dabigatran and warfarin; there was no significant difference between rivaroxaban and warfarin in all seven included studies. The risk was significantly lower with apixaban versus rivaroxaban (n = 7 of 7) but not significantly different from dabigatran (n = 6 of 7). MB risk was significantly lower (n = 3 of 4) or not significantly different (n = 1 of 4) with dabigatran versus rivaroxaban. No evidence was identified for edoxaban.

CONCLUSION

DOACs were associated with similar or lower risks of MB versus warfarin. A lower MB risk was consistently observed for apixaban, but less consistently for dabigatran; MB risk was similar between rivaroxaban and warfarin. Among DOACs, the risk of MB with apixaban was consistently lower than with rivaroxaban, but similar to dabigatran.

Comparison of the Non-VKA Oral Anticoagulants Apixaban, Dabigatran, and Rivaroxaban in the Extended Treatment and Prevention of Venous Thromboembolism: Systematic Review and Network Meta-Analysis

Background

Historically, warfarin or aspirin have been the recommended therapeutic options for the extended treatment (>3 months) of VTE. Data from Phase III randomised controlled trials (RCTs) are now available for non-VKA oral anticoagulants (NOACs) in this indication. The current systematic review and network meta-analysis (NMA) were conducted to compare the efficacy and safety of anticoagulants for the extended treatment of VTE.

Methods

Electronic databases (accessed July 2014 and updated April 2016) were systematically searched to identify RCTs evaluating apixaban, aspirin, dabigatran, edoxaban, rivaroxaban, and warfarin for the extended treatment of VTE. Eligible studies included adults with an objectively confirmed deep vein thrombosis, pulmonary embolism or both. A fixed-effect Bayesian NMA was conducted, and results were presented as relative risks (RRs). Sensitivity analyses examining (i) the dataset employed according to the time frame for outcome assessment (ii) the model used for the NMA were conducted.

Results

Eleven Phase III RCTs (examining apixaban, aspirin, dabigatran, rivaroxaban, warfarin and placebo) were included. The risk of the composite efficacy outcome (VTE and VTE-related death) was statistically significantly lower with the NOACs and warfarin INR 2.0–3.0 compared with aspirin, with no significant differences between the NOACs. Treatment with apixaban (RR 0.23, 95% CrI 0.10, 0.55) or dabigatran (RR 0.55, 95% Crl 0.43, 0.71) was associated with a statistically significantly reduced risk of ‘major or clinically relevant non-major bleed’ compared with warfarin INR 2.0–3.0. Apixaban also showed a significantly reduced risk compared with dabigatran (RR 0.42, 95% Crl 0.18, 0.97) and rivaroxaban (RR 0.23, 95% Crl 0.09, 0.59). Sensitivity analyses indicate that results were dependent on the dataset, but not on the type of NMA model employed.

Conclusions

Results from the NMA indicate that NOACs are an effective treatment for prevention of VTE or VTE-related death) in the extended treatment setting. However, bleeding risk differs between potential treatments, with apixaban reporting the most favourable profile compared with other NOACs, warfarin INR 2.0–3.0, and aspirin.

Abstract P1-11-07: The relationship between breast cancer progression and workplace productivity in the US

Background: A significant proportion of women with breast cancer leave employment due to their disease. Little is known about the effects of breast cancer progression on productivity among those who remain employed. We sought to determine the effect of disease progression on workplace productivity among women with breast cancer.

Methods: By linking health insurance claims data to workplace productivity data, a longitudinal dataset of women with breast cancer was constructed. The study cohort consisted of commercially insured women aged 18 to 64 in the US who were treated for any type of breast cancer between 2005 and 2012. Disease stage was measured through diagnosis codes and treatments observed, to classify women into the following breast cancer groups in each 90-day quarter: local; locally advanced; other non-metastatic; metastatic, 1st line therapy; metastatic, 2nd line therapy; metastatic, ≥ 3rd line therapy; metastatic, end-of-life care. Progression was defined as movement to a more advanced disease stage. Workplace productivity was measured as employment status and total hours away from work per quarter. Covariates included employer industry, comorbidities, age, region of residence, and a time trend. Reduced workplace productivity was valued using average U.S. wages by industry. Kaplan Meier analysis was used to test whether women whose cancer progressed were more likely to drop out of our employment-based sample. Linear and Heckman models were used to measure the effect of disease progression on workplace hours missed. The Heckman model was used to correct for selection bias, given that healthier women may be more likely to remain in our employment-based dataset.

Results: The study cohort included 6,409 women. Mean patient age was 52.0 years (SD: 7.7). The mean number of Charlson comorbidities was 0.52 per patient (SD: 2.9). The majority of our employment-based sample had non-metastatic breast cancer (90.7%). Breast cancer progression was associated with a lower probability of employment (hazard ratio = 0.65, P<0.01). Patients who left our employment-based dataset by the 12th quarter had a greater number of comorbidities (P<0.01) and missed a greater number of hours in the first two quarters (P<0.1), compared with those who remained. This indicated that patients leaving our employment-based sample were less healthy than those who stayed, supporting the use of the Heckman model. According to the Heckman results, progression was associated with increased workplace hours missed per quarter, both when comparing early versus late stage (P<0.001), and first-line versus later-line metastatic therapy (P<0.05). Linear results were similar. Using the Heckman results, the annual valuation of work missed per patient was $29,881 for patients without metastases and $34,141 for patients with, indicating that progression to metastatic cancer adds an additional $6,500 of lost work time, or about 14% of average US wages.

Conclusions: Breast cancer progression leads to increased workplace hours missed, with greater hours missed among those with more advanced disease. Avoiding or delaying disease progression could bring productivity gains to the workplace in addition to the benefits to the patient.

Support: This study was funded by Pfizer Inc.

Citation Format: Yin W, Horblyuk R, Perkins JJ, Sison S, Smith G, Snider JT, Wu Y, Philipson TJ. The relationship between breast cancer progression and workplace productivity in the US. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-11-07.