Cost-Effectiveness of Bridging Anticoagulation Among Patients with Nonvalvular Atrial Fibrillation

Modelling anticoagulation and health-related quality of life in those with atrial fibrillation: a secondary analysis of AFFIRM

Associations of anticoagulation with primary endpoints in longitudinal studies are impacted by selection bias and time-varying covariates (e.g. comorbidities). We demonstrate how time-varying covariates and selection bias influence association estimates between anticoagulation and health-related quality of life (HRQoL) in patients with atrial fibrillation. We performed a secondary analysis of the Atrial Fibrillation Follow-up Investigation of Rhythm Management trial quality of life substudy. Dichotomized warfarin use was ascertained at the study baseline, 2 months later, and annually for up to 6 years. HRQoL was measured at every time point using a self-reported ordinal 5-point Likert-scale (lower score and lower odds ratio represents better health-related quality of life). Static and time-varying covariates were ascertained throughout the study period. Confounder-adjusted generalized mixed model and generalized estimating equation regressions were used to demonstrate traditional association estimates between anticoagulation and HRQoL. Inverse probability of treatment and censorship weights were used to ascertain the influence of time-varying confounding and selection bias. Age-stratified analysis (age ≥ 70 years) evaluated for effect modification. 656 individuals were included in the analysis, 601 on warfarin at baseline. The association of warfarin use with better HRQoL over time strengthened when accounting for time-varying confounding and selection bias (OR 0.30, 95% CI 0.14-0.55) compared to traditional analyses (OR 0.61, 95% CI 0.38-0.97), and was most pronounced in those ≥ 70 years upon stratified analysis. Anticoagulation is associated with higher HRQoL in patients with atrial fibrillation, with time-varying confounding and selection bias likely influencing longitudinal estimates in anticoagulation-HRQoL research.

Bridging vs Non-Bridging with Warfarin Peri-Procedural Management: Cost and Cost-Effectiveness Analyses

The warfarin peri-procedural management in Qatar is predominantly based on bridging (63%), compared to non-bridging. This study sought to perform a first-time cost analysis of current warfarin peri-procedural management practices, including a cost-effectiveness analysis (CEA) of predominant bridging vs predominant non-bridging practices. From the hospital perspective, a one-year decision-analytic model followed the cost and success consequences of the peri-procedural warfarin in a hypothetical cohort of 10,000 atrial fibrillation patients. Success was defined as survival with no adverse events. Outcome measures were the cost and success consequences of the 63% bridging (vs not-bridging) practice in the study setting, ie, Hamad Medical Corporation, Qatar, and the incremental cost-effectiveness ratio (ICER, cost/success) of the warfarin therapy when predominantly bridging based vs when predominantly non-bridging based. The model was based on Monte Carlo simulation, and sensitivity analyses were performed to confirm the robustness of the study conclusions. As per 63% bridging practices, the mean overall cost of peri-procedural warfarin management per patient was USD 3,260 (QAR 11,900), associated with an overall success rate of 0.752. Based on the CEA, predominant bridging was dominant (lower cost, higher effect) over the predominant non-bridging practice in 62.2% of simulated cases, with a cost-saving of up to USD 2,001 (QAR 7,303) at an average of USD 272 (QAR 993) and was cost-effective in 36.9% of cases. Being between cost-saving and cost-effective, compared to predominant non-bridging practices, the predominant use of bridging with warfarin seems to be a favorable strategy in atrial fibrillation patients.

Cost of incorrect application of antithrombotic prophylaxis prior to invasive procedures

BACKGROUND

We analyze the cost of an incorrect application, by the haematologist, of bridging anticoagulation in patients with low-risk atrial fibrillation (AF) needing interruption of treatment prior to a scheduled invasive procedure. Although not recommended, bridging therapy is widely used, resulting in avoidable costs and increased workload.

METHODS

Observational retrospective study. We recorded demographic and clinical data including age, sex, type of procedure, use of bridging therapy with low molecular weight heparin (LMWH), and haemorrhagic complications within 30 days of acenocoumarol withdrawal.

RESULTS

Acenocoumarol was stopped in 161 patients, 97 (60%) were male and 64 (40%) female. Average age was 76,11 ± 8,45 years. Procedures included: minor surgical intervention 58 (36%), colonoscopy 61 (38%), gastroscopy 11 (7%), breast biopsy 4 (2.5%), prostate biopsy 4 (2.5%), infiltration 5 (3%), and other 18 (11%). All patients received bridging anticoagulation with LMWH (40 mg enoxaparin per day) 3 days before and 3 days after the procedure (6 doses). We used a total of 966 doses, at €4.5 per unit, resulted in €4347 of total cost. No complications occurred in 156 patients (97%). Haemorrhage was observed in 5 cases: 1 major haemorrhage needing 6 days of hospital stay and transfusion, and 4 minor haemorrhages (2 patients needed emergency attendance and 2 required hospital admission for 3 and 2 days, respectively). The cost of emergency care was €237.36, and the cost of hospital stay was €6860.81 (€623.71 per day, for 11 days). The total cost of the incorrect application of the protocol was €11,445.17.

CONCLUSION

Guidelines about bridging anticoagulation in low risk AF patients undergoing scheduled invasive procedures were not followed. This practice increments the complications and supposes an increase in costs besides to an inadequate use of the human resources.