Direct costs of warfarin treatment among patients with atrial fibrillation in a Finnish health care setting

OBJECTIVE: The main objective was to estimate the mean direct costs of warfarin treatment for atrial fibrillation (AF) patients. Secondly, the costs of initiating warfarin treatment during a 60-day period and the impact of International Normalized Ratio (INR) and co-morbidities on costs were estimated. DESIGN AND DATA: The study was performed as a retrospective cohort study over a 12-month period in a Finnish communal health care setting. All AF patients aged 65 years or older (n = 250) with warfarin treatment were identified from the database of the health service district of an urban area. Patient specific information related to comorbidities, INR-control, complications and health care resource use were collected. Cost information was obtained from the Finnish national health care unit cost list. METHODS: The effect of treatment balance and other background variables on treatment costs were evaluated using ordinary least squares regression (OLS), log-transformed OLS and generalized linear model (GLM). The mean costs were calculated on the basis of the different models and bias corrected and accelerated (BCa) bootstrap confidence intervals (CIs) were calculated for the mean costs. RESULTS: The best fitting cost model was log-transformed OLS. The costs of warfarin treatment on the basis of the log-transformed model were 589.82 Euros (BCa 95% CI: 586.68-591.99) per patient compared to 616.00 Euros (BCa 95% CI: 579.98-652.96) obtained with the OLS-model. For the treatment initiation period, the mean costs were 263 Euros (BCa 95% CI: 218.90-314.71). Depending on the way that INR-control was defined, the mean costs were 95.27 Euros or 166.92 Euros higher for patients who were not in the defined INR-balance. CONCLUSIONS: The INR-control has a significant impact on the warfarin treatment costs. The choice of model influences the estimated mean costs. In addition, different models identify statistically significant effects between different background variables and costs.     

Safety,effectiveness, and health care cost comparisons among elderly patients with venous thromboembolism prescribed warfarin or apixaban in the United States Medicare population

Abstract

Objective: To compare safety, effectiveness, and healthcare costs of major bleeding (MB), clinically relevant non-major (CRNM) bleeding, recurrent venous thromboembolism (VTE), and all-cause hospitalization among elderly Medicare VTE patients prescribed warfarin vs apixaban.

Methods: Using 100% Medicare data, elderly patients prescribed apixaban or warfarin within 30 days after a VTE encounter were identified. Patients had continuous health plan enrollment and no parenteral or oral anticoagulant use ≤6 months preceding the VTE encounter. Cohorts were balanced using 1:1 propensity score matching (PSM). Cox proportional hazard models were used to assess the risk of MB, CRNM bleeding, recurrent VTE, and all-cause hospitalization. Generalized linear and two-part models were used to estimate MB-, recurrent VTE-, and all-cause related costs (per patient per month [PPPM]).

Results: In the pre-matched cohort, 25,284 (66.9%) patients were prescribed warfarin and 12,515 (33.1%) apixaban. After 1:1 PSM, 11,363 matched pairs of apixaban-warfarin patients were included for a mean follow-up of 4.0 and 4.4 months, respectively. Matched cohorts had a mean age of 78 years and mean Charlson Comorbidity Index score of 2.9. Warfarin was associated with a higher risk of MB (hazard ratio [HR]?=?1.31; 95% confidence interval [CI]?=?1.10–1.57) and CRNM bleeding (HR?=?1.31; 95% CI?=?1.19–1.43) vs apixaban. The risks of recurrent VTE (HR?=?0.96; 95% CI?=?0.70–1.33) and all-cause hospitalization (HR?=?1.05; 95% CI?=?0.99–1.12) were similar among warfarin and apixaban patients. Warfarin patients had higher MB-related ($147 vs $75; p?=?.003) and all-cause costs PPPM ($3,267 vs $3,033; p?<?.001), but similar recurrent VTE-related medical costs PPPM ($30 vs $36; p?=?.516) vs apixaban patients.

Conclusions: Warfarin was associated with significantly higher risk of MB and CRNM bleeding as well as higher MB-related and all-cause costs vs apixaban patients. Recurrent VTE risk and costs were similar among warfarin and apixaban patients.     

Comparison of health care costs and co-morbidities between men diagnosed with benign prostatic hyperplasia and cardiovascular disease (CVD) and men with CVD alone in a US commercial population

ABSTRACT

Objective: The purpose of this study was to compare costs and treatment patterns between men with concomitant benign prostatic hyperplasia (BPH) and CVD to men with CVD (but not BPH).

Study design: A retrospective, matched cohort study was utilized to assess costs and treatment between two study populations.

Methods: The data source was administrative claims from managed care organizations between January 1, 1997 and December 31, 2004. A control group of men with CVD only was created matching by age, index CVD diagnosis date, and CVD diagnoses. Diagnosis and procedure codes identified men with BPH and CVD. Differences in medical costs, co-morbidities, and drug treatments were assessed.

Results: Approximately 39% of men identified with BPH also had some form of CVD at the time of BPH diagnosis. Men with BPH and CVD were more likely to have additional co-morbidities, more frequently received medications for CVD and non-CVD disorders, had 44% higher total medical costs than men with CVD only (?p < 0.001), and had 42% higher CVD-related costs (?p < 0.001) than men with CVD only.

Limitations: The population studied in this analysis was primarily working individuals with health benefits provided by managed care plans; therefore, the results may not generalize to other populations.

Conclusions: This study demonstrates in a commercial payer population that men with concomitant BPH and CVD have more co-morbidities, receive pharmacologic agents more frequently, and have higher health care resource utilization than men with CVD only. Due to the high prevalence of co-morbid BPH and CVD, screening for BPH in men presenting with CVD may assist with earlier disease identification and cost management over time.     

Predictors of high-cost managed care patients with acute coronary syndrome

ABSTRACT

Objective: To develop predictive models of high-cost acute coronary syndrome (ACS) patients using demographic, disease, and treatment characteristics.

Study design: This was a retrospective, administrative claims analysis utilizing pharmacy, medical, and eligibility data from a large US managed care organization.

Methods: ACS was defined by ICD-9 codes for unstable angina (UA) or acute myocardial infarction (AMI). New onset patients (without ACS claims) in the prior six months were identified for the time period 07/01/99–06/30/01, and followed up to 12 months, health plan disenrollment, or death. Cost was measured as that incurred during the initial episode plus subsequent follow-up or during the subsequent follow-up only. Patients were dichotomized as high-cost (top 20%) or low-cost (bottom 80%), based on total costs. Logistic regression was used to examine the association for being classified as high-cost.

Results: A total of 13?731 patients were included: 51.7% with UA, 39.6% with AMI and 8.7% with both UA and AMI. The mean age was 54.2 years and 68.2% were male. A number of co-morbidities (hypertension, diabetes, heart failure, etc.) predicted high-cost patients. Among medications, prior ACE inhibitor use predicted high-cost patients. While revascularization procedures, in general, were strong predictors of high-cost, revascularization during the index ACS episode (opposed to revascularization during the follow-up) decreased the odds of being high-cost (odds ratio [95% CI] 0.615 [0.506–0.748]).

Conclusion: High-cost patients with new onset ACS can be predicted by some characteristics, but many of these characteristics are non-modifiable co-morbidities. Payers and providers may find opportunities for clinical and cost-saving interventions for these patients.     

Warfarin time in therapeutic range and its impact on healthcare resource utilization and costs among patients with nonvalvular atrial fibrillation

Background:

Warfarin is efficacious for reducing stroke risk among patients with nonvalvular atrial fibrillation (NVAF). However, the efficacy and safety of warfarin are influenced by its time in therapeutic range (TTR).

Objective:

To assess differences in healthcare resource utilization and costs among NVAF patients with low (<60%) and high (≥60%) warfarin TTRs in an integrated delivery network (IDN) setting.

Methods:

Patients with NVAF were identified from an electronic medical record database. Patients were required to have ≥6 international normalized prothrombin time ratio (INR) tests. NVAF patients were grouped into two cohorts: those with warfarin TTR <60% (low TTR) and those with warfarin TTR ≥60% (high TTR). Healthcare resource utilization and costs were evaluated during a 12 month follow-up period. Multivariable regressions were used to assess the impact of different warfarin TTRs on healthcare costs.

Results:

Among the study population, greater than half (54%, n?=?1595) had a low TTR, and 46% (n?=?1356) had a high TTR. Total all-cause healthcare resource utilization was higher among patients in the low TTR cohort vs. the high TTR cohort (number of encounters: 70.2 vs. 56.1, p?<?0.001). After adjusting for patient characteristics, total all-cause healthcare costs and stroke-related healthcare costs were $2398 (p?<?0.001) and $687 (p?=?0.02) higher, respectively, for patients in the low TTR cohort vs. the high TTR cohort.

Limitations:

In this retrospective study, we were only able to evaluate the association and not the causality between healthcare resource utilization and costs with the different warfarin TTRs.

Conclusion:

Many warfarin-treated NVAF patients have a low warfarin TTR. NVAF patients with low vs. patients with high warfarin TTR used healthcare resources to a greater extent, which was reflected in higher healthcare costs.     

Risk of stroke/systemic embolism,major bleeding and associated costs in non-valvular atrial fibrillation patients who initiated apixaban,dabigatran or rivaroxaban compared with warfarin in the United States Medicare population

Objective: To compare the risk and cost of stroke/systemic embolism (SE) and major bleeding between each direct oral anticoagulant (DOAC) and warfarin among non-valvular atrial fibrillation (NVAF) patients.

Methods: Patients (≥65 years) initiating warfarin or DOACs (apixaban, rivaroxaban, and dabigatran) were selected from the Medicare database from 1 January 2013 to 31 December 2014. Patients initiating each DOAC were matched 1:1 to warfarin patients using propensity score matching to balance demographics and clinical characteristics. Cox proportional hazards models were used to estimate the risks of stroke/SE and major bleeding of each DOAC vs. warfarin. Two-part models were used to compare the stroke/SE- and major-bleeding-related medical costs between matched cohorts.

Results: Of the 186,132 eligible patients, 20,803 apixaban–warfarin pairs, 52,476 rivaroxaban–warfarin pairs, and 16,731 dabigatran–warfarin pairs were matched. Apixaban (hazard ratio [HR]?=?0.40; 95% confidence interval [CI] 0.31, 0.53) and rivaroxaban (HR?=?0.72; 95% CI 0.63, 0.83) were significantly associated with lower risk of stroke/SE compared to warfarin. Apixaban (HR?=?0.51; 95% CI 0.44, 0.58) and dabigatran (HR?=?0.79; 95% CI 0.69, 0.91) were significantly associated with lower risk of major bleeding; rivaroxaban (HR?=?1.17; 95% CI 1.10, 1.26) was significantly associated with higher risk of major bleeding compared to warfarin. Compared to warfarin, apixaban ($63 vs. $131) and rivaroxaban ($93 vs. $139) had significantly lower stroke/SE-related medical costs; apixaban ($292 vs. $529) and dabigatran ($369 vs. $450) had significantly lower major bleeding-related medical costs.

Conclusions: Among the DOACs in the study, only apixaban is associated with a significantly lower risk of stroke/SE and major bleeding and lower related medical costs compared to warfarin.     

A Markov cost-utility analysis of escitalopram and duloxetine for the treatment of major depressive disorder

ABSTRACT

Objective: To estimate the costs and quality-adjusted life weeks of duloxetine and escitalopram.

Research design: A probabilistic Markov cost-utility analysis with a time horizon of 1 year using data from placebo controlled randomized clinical trials for both products.

Methods: Efficacy was defined as remission of depressive symptoms and converted to utilities. Side effects were incorporated using rates from clinical trials and converted to utilities to define treatment effective­ness. The effectiveness outcome was quality adjusted life weeks (QALWs). Estimates of effectiveness (efficacy and side effects) used beta distributions and costs used gamma distributions. Using a managed care perspective, medication costs and physician office visits were included in the model, along with costs associated with treatment failure. Antidepressant costs were obtained using average wholesale price minus 20%. Physician visit costs were obtained from the 2006 US Medicare fee schedule for physician services. A Monte Carlo simulation was conducted using 1000 trials with both first- and second-order sampling.

Results: Over 1 year, the estimated mean quality-adjusted life weeks was 41.0 (95% confidence interval [CI]: 40.7–41.3) for escitalopram and 38.2 (95% CI: 37.9–38.4) for duloxetine. The mean annual total medical cost for escitalopram was $907 (95% CI: $894–$919) and $1633 (95% CI: $1614–$1654) for duloxetine. Limitations to this analysis include using separate studies examining the efficacy and adverse events of either escitalopram or duloxetine, assuming the switch, augmentation, and titration rates for duloxetine to be similar to escitalopram, and using utility estimates from published literature for the antidepressant adverse events.

Conclusion: This analysis suggests that escitalopram was more effective in terms of QALWs and less costly than duloxetine for treatment of depression.     

Effect of the novel oral dipeptidyl peptidase IV inhibitor vildagliptin on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects*

ABSTRACT

Objective: Vildagliptin is a potent and selective dipeptidyl peptidase?IV (DPP?4) inhibitor that improves glycemic control in patients with type 2 diabetes by increasing alpha and beta-cell responsiveness to glucose. This study assessed the effect of multiple doses of vildagliptin 100?mg once daily on warfarin pharmacokinetics and pharmacodynamics following a single 25?mg oral dose of warfarin sodium.

Research design and methods: Open-label, randomized, two-period, two-treatment crossover study in 16 healthy subjects.

Results: The geometric mean ratios (co-administration vs. administration alone) and 90% confidence intervals (CIs) for the area under the plasma concentration-time curve (AUC) of vildagliptin, R- and S?warfarin were 1.04 (0.98, 1.11), 1.00 (0.95, 1.04) and 0.97 (0.93, 1.01), respectively. The 90% CI of the ratios for vildagliptin, R- and S?warfarin maximum plasma concentration (C_max) were also within the equivalence range 0.80–1.25. Geometric mean ratios (co-administration vs. warfarin alone) of the maximum value and AUC for prothrombin time (PT_max, 1.00 [90% CI 0.97, 1.04]; AUC_PT, 0.99 [0.97, 1.01]) and international normalized ratios (INR_max, 1.01 [0.98, 1.05]; AUC_INR, 0.99 [0.97, 1.01]) were near unity with the 90% CI within the range 0.80–1.25. Vildagliptin was well tolerated alone or co-administered with warfarin; only one adverse event (upper respiratory tract infection in a subject receiving warfarin alone) was reported, which was judged not to be related to study medication.

Conclusions: Co-administration of warfarin with vilda­gliptin did not alter the pharmacokinetics and pharmaco­dynamics of R- or S?warfarin. The pharmacokinetics of vildagliptin were not affected by warfarin. No dosage adjustment of either warfarin or vildagliptin is necessary when these drugs are co-medicated.     

An economic model of adverse events and costs for oral anticoagulants used for atrial fibrillation

ABSTRACT

Objective: To construct a semi-Markov model to compare health outcomes and medical costs associated with warfarin and a second anticoagulant over 1- and 5-year periods.

Design: We posited a hypothetical cohort of 10?000 identical 70-year-old patients with atrial fibrillation. We posited 20 scenarios for events that included four possibilities for ischemic strokes (mild, moderate, severe, death) and 16 possibilities for hemorrhages. The model allowed for four levels of International Normalized Ratio. Event rates were based on outcomes in clinical trials and observational studies. Costs were estimated from the perspective of the third-party payer.

Results: The greatest cost-generating events were virtually the same for the two drugs and included severe stroke ($1?758?548 for 1 year for both drugs), moderate stroke ($380?355 for 1 year for both drugs), and severe lower gastrointestinal (GI) hemorrhage ($193?804 for 1 year for warfarin and $193?474 for second drug). The least costly events for both drugs were mild intracranial or intracerebral hemorrhage ($7584 for warfarin and $4314 for second drug) and fatal upper GI hemorrhage ($16?781 and $16?752). Total costs for adverse events over 5 years were similar: $18?330?662 for warfarin and $17?102?847 for the second drug. Fatalities for 5 years were 123 for warfarin and 101 for the non-warfarin drug. Varying assumptions for nursing home care and numbers of ischemic strokes and hemorrhages generated the widest variation in costs.

Limitations: We did not account for out-of-pocket expenses, ‘pain and suffering’ costs, or variation across practice settings.

Conclusions: There was substantial variation in numbers and costs of adverse events across 20 scenarios, and for fatalities between the two drugs, but variation in costs between the two drugs was modest.     

Increasing economic burden of tyrosine kinase inhibitor treatment failure by line of therapy in chronic myeloid leukemia

Objective:

To assess the economic burden of tyrosine kinase inhibitor (TKI) treatment failure in chronic myeloid leukemia (CML), by assessing all-cause health care resource use (HCRU) and costs in the year after treatment failure by line of therapy (LOT; 1L/2L/3L) using real-world data.

Methods:

Treatment episodes initiating a TKI of interest (index TKI) during June 2008–December 2011 were identified from the IMS PharMetrics Plus Health Plan Claims Database for adult patients with CML diagnosis (ICD-9-CM 205.1x), 120 days pre-index continuous enrollment (CE) and no clinical trial participation. Episodes experiencing treatment failure, defined as switch to a non-index TKI or discontinuation of index TKI (gap of?≥?60 days), and with 1 year CE post-failure, were analyzed. LOT was determined by number of unique TKIs used in the pre-index. All-cause HCRU and costs (2012 USD) in the 1 year post-failure were assessed by LOT, and the comparisons between 1L and 2L failures were also adjusted using multivariate generalized linear models (GLMs) to control for underlying differences.

Results:

A total of 706 episodes were identified (518 1L; 180 2L; 8 3L). Unadjusted HCRU over 1 year post-failure increased significantly. This was accompanied by a significant increase in unadjusted mean costs for 2L failures vs. 1L failures ($99,624 vs. $78,667, p?=?0.021, Δ$20,957). Following the adjustment using GLMs, adjusted mean costs were 38% higher (95% CI 1.14–1.68), driven primarily by use of medical services. In adjusted analyses, compared to 1L, 2L failures had: 45% more ambulatory visits (mean 31 vs. 21, 95% CI 1.26–1.66), 75% higher risk of hospitalization (33% vs. 23% hospitalized, 95% CI 1.16–2.64), and 73% higher medical costs (95% CI 1.31–2.29). Medical costs comprised a greater proportion of total costs in 2L vs. 1L (55% vs. 44%); pharmacy costs did not increase significantly.

Conclusions:

The economic burden over 1 year post TKI failure increased with each sequential line of TKI treatment failure.     

Anticoagulation in patients with non-valvular atrial fibrillation: an evaluation of stability and early factors that predict longer-term stability on warfarin in a large UK population

ABSTRACT

Objective: To determine the proportion of patients with non-valvular atrial fibrillation (NVAF) treated with warfarin that achieved a 6‐month period within the target INR range (stability). To then evaluate any associations between stability and outcome and to determine whether stability can be predicted by clinical factors at an early stage in warfarin treatment.

Methods: This study was a record linkage study in 1513 patients with NVAF treated with warfarin for a minimum of 6‐months, carried out in a large UK population. The main outcome measures were stability (defined as six months within the target INR range [2.0–3.0]), thromboembolic and bleeding event rates and mortality. Secondary outcome measures were the predictive value of baseline characteristics and other treatment variables.

Results: Stability was achieved in 52% of the study group. Standardised mean survival was significantly higher in the group who achieved stability (? = 16.91 months, p < 0.001) with a hazard ratio of 4.36 (?p < 0.001). The stable group had a lower rate of both thromboembolic events (0.8% vs. 2.3% per patient year) and bleeds recorded on inpatient diagnoses (0.4% vs. 1.2% per patient year). Failure to achieve stable control was associated with age (Odds Ratio [OR] 1.011 (95% Confidence Interval [CI] 1.001–1.021)) and morbidity at baseline (OR 1.015; 95% CI 1.007–1.022). An increase in mean time between visits (OR 0.939; 95% CI 0.926–0.952) and the percentage time in range (OR 0.889; 95% CI 0.879–0.900) was associated with a decrease in the chance of instability. Greater variability in INR was also associated with a failure to achieve stability (OR 1.518; 95% CI 1.427–1.615). Receiver Operator Characteristic (ROC) analysis using data from the first three months of treatment demonstrated good discrimination of stability using age and morbidity at baseline and percentage time in range and frequency of visits during the first three months of treatment (area under curve [AUC] 0.780; standard error [SE] 0.012; 95% CI 0.757–0.803).

Conclusions: Many patients never achieved a period of 6‐months stability and were at increased risk of thromboembolic events and bleeds. Age, morbidity at baseline and variability of INR control in the first three months could be used to predict instability using warfarin. This study infers that patients should be treated more intensively in the early stages of warfarinisation in order to improve outcome.     

Burden of illness of hepatitis C from a managed care organization perspective

SUMMARY

Objectives: The objectives of this study were to: (1) determine the total hepatitis C virus (HCV)-related and total healthcare costs (HCV plus other co-morbidities) of patients with HCV in a managed care organization; (2) determine total healthcare costs of HCV patients with and without a human immunodeficiency virus (HIV) infection as a co-morbidity.

Methods: The study design was a retrospective analysis of a medical and pharmacy claims database of patients diagnosed with HCV in a 325000 member managed care organization. Patients diagnosed with HCV and 12 months of continuous eligibility in the managed care organization from January 1997 through December 1999 were included in the study. The main outcome measures of the study were the total healthcare costs and HCV-related healthcare costs and the impact of HIV as a co-morbidity on these costs.

Results: The study identified 614 patients meeting the inclusion criteria. The study population was 58% male and had a mean age of 46 (± 10.6)years. In patients receiving interferon-α, their median total healthcare costs exceeded $4600 and the median HCV-related costs exceeded $2470. The total healthcare costs of HCV patients with HIV as a co-morbidity were significantly larger than patients without this co-morbidity.

Conclusion: HCV represents a very important disease to managed care organizations. Patients with this disease require costly drug therapies and consume significant health care resources. Additional research is needed to more fully characterize future clinical and economic outcomes as new agents become available.     

Treatment patterns and real-world effectiveness of warfarin in nonvalvular atrial fibrillation within a managed care system

ABSTRACT

Objective: To examine warfarin utilization and clinical effectiveness among patients with nonvalvular atrial fibrillation within usual clinical care in a managed care system.

Research design and methods: A retrospective analysis of health care claims for an approximately four million member managed care organization was performed. Health plan members with a diagnosis of nonvalvular atrial fibrillation in calendar year 2000 were identified and stratified into two cohorts: Warfarin Therapy (newly initiating warfarin) or Warfarin Candidates (eligible for warfarin therapy according to the ACC/AHA/ESC Guidelines for the Management of Patients with Atrial Fibrillation, but did not receive warfarin).

Measurements: The occurrence of thromboembolism, ischemic stroke, and hemorrhage during a maximum 720‐day follow-up were compared between cohorts, adjusting for age, gender, and other risk factors, using Cox regression.

Results: Among 12?539 subjects (mean age 78.0 ± 8.8 years) with nonvalvular atrial fibrillation, 4895 (39.0%) initiated Warfarin Therapy and 7644 (61.0%) were Warfarin Candidates. Event occurrences among Warfarin Therapy vs. Warfarin Candidates were: ischemic stroke, 3.7% vs. 4.5%; any thromboembolism, 7.8% vs. 10.8%; and hemorrhage, 4.4% vs. 4.9%, respectively. Warfarin therapy was not associated with an increased risk for hemorrhage (hazard ratio [HR] = 0.97, 95% confidence interval [CI] = 0.82–1.15), while risks for ischemic stroke and any thromboembolism were significantly reduced, by 22% (HR = 0.78, 95% CI = 0.65–0.93) and 34% (HR = 0.66, 95% CI = 0.59–0.75), respectively.

Conclusions: Within usual clinical care for the managed care population examined, warfarin remains underused despite current guidelines recommending its use in nearly all patients with nonvalvular atrial fibrillation. Although utilization of anticoagulation clinics and INR values attained were unknown in this study, the observed risk reductions for ischemic stroke and thromboembolism were lower than those achieved in clinical trials, while no increased risk for hemorrhage was observed. These findings suggest that warfarin is used conservatively, and dosed cautiously, diminishing the full potential benefit of anticoagulant therapy in patients with nonvalvular atrial fibrillation.     

Continuation with apixaban treatment is associated with lower risk for hospitalization and medical costs among elderly patients

Objective: To compare the risk of hospitalization and costs associated with major bleeding (MB) or stroke/systemic embolism (SE) among elderly patients with nonvalvular atrial fibrillation (NVAF) who initiated apixaban then switched to another oral anticoagulant (OAC) vs. those who continued with apixaban treatment.

Methods: NVAF patients (≥65?years) initiating apixaban were identified from the Humana database (1 January 2013–30 September 2017) and grouped into switcher and continuer cohorts. For switchers, the earliest switch from apixaban to another OAC was defined as the index event/date. A random date during apixaban treatment was selected as the index date for continuers. Patients were followed from index date to health plan disenrollment or 31 December 2017, whichever was earlier. Multivariable regression analyses were used to examine the association of switchers vs. continuers with risk of MB-related or stroke/SE-related hospitalization and healthcare costs during follow-up.

Results: Of 7858 elderly NVAF patients included in the study, 14% (N?=?1110; mean age: 78?years) were switchers; 86% (N?=?6748; mean age: 79?years) were continuers. Apixaban switchers vs. continuers had significantly greater risk of MB-related hospitalization (hazard ratio [HR]: 2.00; 95% CI: 1.52–2.64; p?<?.001) during follow-up; risk of stroke/SE hospitalization did not differ significantly (HR: 1.36, 95% CI: 0.89–2.06, p?=?.154). MB- and stroke/SE-related medical costs were higher for switchers vs. continuers, although total all-cause healthcare costs were similar.

Conclusion: Elderly patients with NVAF in the US who continued with apixaban treatment had a lower risk of MB-related hospitalization and lower MB- and stroke/SE-related medical costs compared to patients who switched to another OAC.     

Effect of oral diuretics on chronic warfarin therapy: a retrospective study

Background: Limited clinical documentation is suggestive of a drug interaction between warfarin and diuretics.

Objective: To evaluate the effect on international normalized ratio (INR) when a daily oral diuretic is started or increased in patients on chronic stable warfarin therapy.

Methods: The medical records of all active patients of two hospital-based anticoagulation clinics were retrospectively reviewed to identify patients who were started on or received a dose increase of a daily oral diuretic while on stable warfarin therapy. The primary endpoint was the mean difference between an INR recorded within 30 days prior to the diuretic initiation (pre-INR) and an INR recorded within 30 days after diuretic initiation (post-INR).

Results: A total of 1254 patient charts were screened and a total of 123 patients met the study criteria. The mean difference in pre-INR and post-INR was 0.09 (95% CI -0.03 to 0.21, p = 0.12). Post-INR values were outside of the patient's therapeutic range in 39 patients (32%), but no major bleeding or thromboembolic events were reported.

Conclusion: Based on this retrospective study, diuretics did not result in a significant change in the INR in patients on stable warfarin therapy.     

The hidden costs of anticoagulation in hospitalized patients with non-valvular atrial fibrillation

Introduction: Non-valvular atrial fibrillation (NVAF) and ischemic stroke are collectively associated with annual hospital costs of tens of billions of dollars in the USA. Oral anticoagulant (OAC) treatment with warfarin reduces the risk of stroke in patients with NVAF. Unfortunately, because of the complexity of warfarin therapy and potential for adverse events (AEs), many patients who might benefit go untreated or receive suboptimal therapy, increasing their stroke and/or bleeding risk.

Areas covered: This review explores current hospital costs and resource utilization for NVAF patients on warfarin therapy and the potential impact of newer OACs in this area.

Expert opinion: Many ischemic strokes could be prevented through wider use of OACs. Further, admissions due to anticoagulant-associated AEs could be reduced by optimizing OAC therapy. In the hospital, specialized anticoagulation services can decrease costs by improving the effectiveness of warfarin management, empowering patients through education and optimizing care transitions. With fewer interactions and no dose titration or monitoring required, the novel OACs (NOACs) have the potential to further decrease inpatient resource utilization and costs. It is important that, as data become available, inpatient costs are included in cost–benefit comparisons between warfarin and the NOACs.     

Healthcare costs among adults with type 2 diabetes initiating saxagliptin or linagliptin: a US-based claims analysis

Objective: To compare healthcare costs of adults with type 2 diabetes (T2D) after initiation of saxagliptin or linagliptin, two antidiabetic medications in the dipeptidyl peptidase-4 inhibitor medication class.

Methods: Patients with T2D who were at least 18 years old and initiated saxagliptin or linagliptin (index date) between 1 June 2011 and 30 June 2014 were identified in the MarketScan Commercial and Medicare Supplemental Databases. All-cause healthcare costs and diabetes-related costs (T2D diagnosis on a medical claim and/or an antidiabetic medication claim) were measured in the 1 year follow-up period. Saxagliptin and linagliptin initiators were matched using propensity score methods. Cost ratios (CRs) and predicted costs were estimated from generalized linear models and recycled predictions.

Results: There were 34,560 saxagliptin initiators and 18,175 linagliptin initiators identified (mean ages 57 and 59; 55% and 56% male, respectively). Before matching, saxagliptin initiators had significantly lower all-cause total healthcare costs than linagliptin initiators (mean?=?$15,335 [SD $28,923] vs. mean =?$20,069 [SD $48,541], p?p?n?=?16,069 per cohort), saxagliptin initiators had lower all-cause follow-up costs than linagliptin initiators (CR?=?0.953, 95% CI?=?0.932–0.974, p?p?=?0.017; predicted costs?=?$3989 vs. $4159).

Conclusions: Adult patients with T2D initiating treatment with saxagliptin had lower total all-cause healthcare costs and diabetes-related medical costs over 1 year compared with patients initiating treatment with linagliptin.     

Pharmacy cost evaluation of risperidone,olanzapine, and quetiapine for the treatment of schizophrenia in acute care inpatient settings

SUMMARY

Objective: This study examines total pharmacy cost and usage patterns of schizophrenic patients in acute mental health inpatient settings for three atypical antipsychotics – risperidone, olanzapine, and quetiapine. Despite the readily available unit cost information for drugs, actual pharmacy costs may deviate significantly from ‘labeled costs’. Recent research findings indicate the need for more robust evaluation of such pharmacy costs.

Research design and methods: This study used data from non-randomized inpatient retrospective charts from three acute care inpatient mental health facilities. The final pooled sample included 327 patients, of which 120 received risperidone, 153 received olanzapine, and 54 received quetiapine. Medication cost was defined as the average wholesale price (AWP) as listed in the 2001 ‘Red Book’. Propensity scoring methodology and multinomial regression were employed to reduce treatment selection bias.

Results: The observed mean daily antipsychotic drug doses were 4.45?mg (SD 2.44) for risperidone, 14.04?mg (SD 5.55) for olanzapine, and 350.33?mg (SD 228.24) for quetiapine. The corresponding mean daily drug costs were $7.66(SD $4.20) for risperidone, $8.11 (SD $5.29) for quetiapine and, $12.10 (SD $4.79) for olanzepine. Numbers adjusted for treatment selection bias show that the average daily total pharmacy cost of risperidone was $4.35 lower than olanzapine (?p < 0.001) and $1.41 lower than quetiapine (?p = 0.38). The adjusted average daily pharmacy cost of olanzapine was $4.02 higher than quetiapine (?p < 0.001). After statistical adjustment there were no significant differences between study drugs in terms of length of stay or patient functioning.

Conclusion: This study provides the first US comparison of medication utilization patterns and pharmacy costs for olanzapine, risperidone, and quetiapine administered in acute mental health care inpatient settings. While this study did not estimate the full economic value of the three antipsychotics in these inpatient settings, it demonstrated that the mean daily costs for risperidone were lower than the mean daily costs for olanzapine (?p < 0.001) and quetiapine although the later difference was not statistically significant (?p = 0.38).