Treatment intensification with bempedoic acid to achieve LDL-C goal in patients with ASCVD: A simulation model using a real-world patient cohort in the US

Background and aims

Guidelines recommend that high-risk patients with atherosclerotic cardiovascular disease (ASCVD) be treated with maximally tolerated statins to lower low-density lipoprotein cholesterol (LDL-C) levels and reduce the risk of major adverse cardiovascular events. In patients whose LDL-C remains elevated, non-statin adjunct therapies, including ezetimibe (EZE), bempedoic acid (BA), and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are recommended.

Methods

The impact of BA and EZE in a fixed-dose combination (FDC) on LDL-C goal attainment was evaluated using a simulation model developed for a United States cohort of high-risk adults with ASCVD. Treatment was simulated for 73,056 patients not at goal (LDL-C >70 mg/dL), comparing BA + EZE (FDC), EZE only, and no oral adjunct therapy (NOAT). The addition of PCSK9 inibitors was assumed after 1 year in patients not at LDL-C goal. Treatment efficacy was estimated from clinical trials. Patient-level outcomes were predicted over a 10-year horizon accounting for treatment discontinuation and general mortality.

Results

Baseline mean age of the cohort was 67 years, most were White (79%) and male (56%). A majority had established coronary artery disease (75%), 48% had diabetes, and mean LDL-C was 103.0 mg/dL. After 1 year, 79% of patients achieved LDL-C goal (mean, 61.1 mg/dL) with BA + EZE (FDC) compared to 58% and 42% with EZE (71.7 mg/dL) and NOAT (78.4 mg/dL), respectively.

Conclusions

This simulation shows that adding BA + EZE (FDC) to maximally tolerated statins would result in more patients achieving LDL-C goal than adding EZE alone or NOAT.

Cost-Effectiveness of Oral Nirmatrelvir/Ritonavir in Patients at High Risk for Progression to Severe COVID-19 in the United States

OBJECTIVES

Nirmatrelvir/ritonavir (NMV/r) is an orally administered antiviral indicated for the outpatient treatment of patients with mild-to-moderate COVID-19 at high risk for disease progression to severe illness. We estimated the cost-effectiveness of NMV/r versus best supportive care for patients with mild-to-moderate COVID-19 at high risk for progression to severe illness from a US health sector perspective.

METHODS

A cost-effectiveness model was developed using a short-term decision-tree (1 year) followed by a lifetime 2-state Markov model (alive and dead). The short-term decision-tree captured costs and outcomes associated with the primary infection and healthcare utilization; survivors of the short-term decision-tree were followed until death assuming US quality-adjusted life years (QALYs), adjusted in the short-term for survivors of mechanical ventilation. Baseline rate of hospitalization and NMV/r effectiveness were taken from an Omicron-era US real-world study. Remaining inputs were informed by previous COVID-19 studies and publicly available US sources. Sensitivity analyses were conducted for all model inputs to test the robustness of model results.

RESULTS

NMV/r was found to decrease COVID-19 related hospitalizations (-0.027 per infected case) increase QALYs (+0.030), decrease hospitalization costs (-$1110), and increase total treatment cost (+$271), resulting in an incremental cost-effectiveness ratio of $8931/QALY. Results were most sensitive to baseline risk of hospitalization and NMV/r treatment effectiveness parameters. The probabilistic analysis indicated that NMV/r has a >99% probability of being cost-effective at a $100 000 willingness-to-pay threshold.

CONCLUSIONS

NMV/r is cost-effective vs best supportive care for patients at high risk for severe COVID-19 from a US health sector perspective.

Estimated impact of ECHELON-1 overall survival on productivity costs in stage III/IV classical Hodgkin lymphoma in the United States

BACKGROUND

A 2010 study on the impact of cancer mortality on productivity costs found Hodgkin lymphoma to have the second largest productivity cost lost per death in the United States. The ECHELON-1 trial demonstrated that frontline brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine (A+AVD) improves overall survival (OS) vs doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) in stage III/IV classical Hodgkin lymphoma (cHL), reducing the risk of death to 41% (hazard ratio = 0.59; 95% CI = 0.40-0.88; P = 0.009).

OBJECTIVES

To assess the estimated impact of frontline treatment choice on mortality and productivity using an oncology simulation model informed by ECHELON-1 data.

METHODS

Individual productivity was estimated using the human capital approach and reported via present value lifetime earnings (PVLE) estimates. Deaths avoided and lifeyears saved without and with A+AVD were calculated using a model informed by realworld treatment use, treatment-specific OS, and expert clinicians' opinions. A+AVD use in the base case was 27% (range: 0%-80%). Stage III/IV cHL prevalence over a 10-year period was estimated; downstream lifetime productivity costs were projected without and with A+AVD.

RESULTS

In 2031, 3,645 patients were estimated to be newly diagnosed with stage III/IV cHL. Over 10 years with 27% A+AVD vs no A+AVD use, estimates predicted 14% fewer deaths (2,290 vs 2,650) and 14% less total PVLE losses ($1.438 vs $1.664 billion). Results from scenario analyses (40%-80% vs no A+AVD use) showed 20% to 32% decreases in PVLE losses ($1.331-$1.137 billion vs $1.664 billion), saving up to $527 million over 10 years.

CONCLUSIONS

Productivity cost losses due to mortality in stage III/IV cHL are high. Increasing A+AVD use for patients with stage III/IV cHL would reduce productivity cost losses as deaths are avoided, based on ECHELON-1 OS results.

Healthcare resource utilization and costs among patients with post-stroke spasticity before and after spasticity management including onabotulinumtoxina

BACKGROUND

Real-world data regarding the impact of onabotulinumtoxinA on healthcare resource utilization and costs for post-stroke spasticity are scarce.

OBJECTIVE

To compare differences in 12-month healthcare resource utilization and costs before and after post-stroke spasticity management including onabotulinumtoxinA.

METHODS

This retrospective claims analysis of IBM MarketScan Commercial and Medicare Supplemental databases included adults with ≥ 1 onabotulinumtoxinA claim for post-stroke spasticity (1 January 2010 to 30 June 2018) and continuous enrolment for ≥ 12 months pre- and post-index (first onabotulinumtoxinA claim date). All-cause and spasticity-related healthcare resource utilization and costs were compared 12 months pre- and post-index (McNemar's χ2 test or paired t-test). A subgroup analysis assessed effect of stroke-to-index interval on costs.

RESULTS

Among 735 patients, mean (standard deviation) stroke-date-to-index-date interval was 284.5 (198.8) days. Decreases were observed post-index for mean all-cause outpatient (62.9 vs 60.5; p ≤ 0.05) and emergency department visits (1.1 vs 0.8; p ≤ 0.0001), and hospital admissions (1.5 vs 0.4; p ≤ 0.0001). Increase in prescription fills (43.0 vs 53.7) was seen post-index. Post-index decreases in all-cause (-66%) and spasticity-related (-51%) costs were driven by reduced inpatient care costs. Findings were consistent regardless of stroke-date-to-index-date interval.

CONCLUSION

Significant reductions in healthcare resource utilization and costs were observed after 1 year of post-stroke spasticity management including onabotulinumtoxinA. Long-term studies are needed to establish causality.

Estimating long-term outcomes in classic Hodgkin lymphoma: a United States population-based oncology simulation model based on overall survival from the ECHELON-1 trial

The six-year ECHELON-1 update showed a survival advantage for frontline (1 L) A + AVD (brentuximab vedotin, doxorubicin, vinblastine, dacarbazine) vs ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) for stage III/IV classic Hodgkin lymphoma (cHL). As clinical trials have limited ability to track patients for extended periods, we developed an oncology simulation model using ECHELON-1 data to estimate population-based cHL outcomes in the US over 10 years (through 2031). The model included a scenario without (64.5% ABVD, 35.5% PET-adapted ABVD utilization) and scenarios with 1 L A + AVD (27%-80%k utilization). At 27%-80% A + AVD utilization, the model estimated 13.6%-31.7% fewer deaths, 2.4%-6.3% more patients ≥5 years progression free, 9.4%-24.4% fewer stem cell transplants (SCTs), and 7.8%-22.5% fewer second cancers over 10 years. These results suggest that the improved outcomes observed in the ECHELON-1 update with A + AVD vs ABVD may translate to more patients alive and fewer with primary relapsed/refractory cHL, SCTs, and second cancers.

Impact of Ruxolitinib Cream on Work Productivity and Activity Impairment and Associated Indirect Costs in Patients with Atopic Dermatitis: Pooled Results From Two Phase III Studies

BACKGROUND

Atopic dermatitis is a chronic inflammatory skin disease that can negatively impact work productivity and daily activities. Ruxolitinib cream, a Janus kinase inhibitor, demonstrated efficacy and safety in patients with atopic dermatitis in two phase III studies (TRuE-AD1 and TRuE-AD2).

OBJECTIVE

This post hoc analysis sought to describe the effects of ruxolitinib cream on work productivity and activity impairment from pooled data from the phase III studies, to estimate indirect costs due to atopic dermatitis, and to estimate the incremental cost savings with ruxolitinib cream versus vehicle cream.

METHODS

Patients in both studies were ≥ 12 years old with atopic dermatitis for ≥ 2 years, an Investigator's Global Assessment score of 2 or 3, and a 3-20% affected body surface area at baseline. Patients were randomized 2:2:1 to receive ruxolitinib cream (0.75% or 1.5%) or vehicle cream for 8 weeks. Patient self-reported productivity in the efficacy-evaluable population was assessed at weeks 2, 4, and 8 using the Work Productivity and Activity Impairment Questionnaire-Specific Health Problem version 2.0. Statistical significance for the two doses versus vehicle was calculated using an analysis of covariance. Work Productivity and Activity Impairment overall work impairment scores were converted to a model of costs per employed patient due to lost productivity and incremental cost savings from ruxolitinib cream treatment using a human capital approach.

RESULTS

Of 1249 patients enrolled (median age, 32 years; female sex, 61.7%), 1208 were included in the efficacy-evaluable population. Patients applying 0.75% or 1.5% ruxolitinib cream had significant changes in overall work impairment (- 17.9% [0.75% strength] and - 15.0% [1.5% strength] vs - 5.7% for vehicle; p < 0.0001 for both) and daily activity impairment (- 20.6% [0.75% strength] and - 21.5% [1.5% strength] vs - 10.6% for vehicle; p < 0.0001 for both). These corresponded to estimated lost productivity costs in 2021 US dollars of $1313 (0.75% strength) and $1242 (1.5% strength) versus $2008 (vehicle) over the 8-week trial period. Compared with a patient receiving vehicle, incremental annual indirect cost savings were estimated to be $5302 with 0.75% ruxolitinib cream and $4228 with 1.5% ruxolitinib cream.

CONCLUSIONS

Ruxolitinib cream therapy is associated with improved work productivity and daily activity compared with vehicle and is estimated to reduce the indirect cost burden on the patient.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT03745638 (registered 19 November, 2018) and NCT03745651 (registered 19 November, 2018).

Cost-Effectiveness of Rifaximin Treatment in Patients with Hepatic Encephalopathy

BACKGROUND

Hepatic encephalopathy (HE) is a complication of cirrhosis of the liver causing neuropsychiatric abnormalities. Clinical manifestations of overt HE result in increased health care resource utilization and effects on patient quality of life. While lactulose has historically been the mainstay of treatment for acute HE and maintenance of remission, there is an unmet need for additional therapeutic options with a favorable adverse event profile. Compared with lactulose alone, rifaximin has demonstrated proven efficacy in complete reversal of HE and reduction in the incidence of HE recurrence, mortality, and hospitalizations. Evidence suggests the benefit of long-term prophylactic therapy with rifaximin; however, there is a need to assess the economic impact of rifaximin treatment in patients with HE.

OBJECTIVE

To assess the incremental cost-effectiveness of rifaximin ± lactulose versus lactulose monotherapy in patients with overt HE.

METHODS

A Markov model was developed in Excel with 4 health states (remission, overt HE, liver transplantation, and death) to predict costs and outcomes of patients with HE after initiation of maintenance therapy with rifaximin ± lactulose to avoid recurrent HE episodes. Cost-effectiveness of rifaximin was evaluated through estimation of incremental cost per quality-adjusted life-year (QALY) or life-year (LY) gained. Analyses were conducted over a lifetime horizon. One-way deterministic and probabilistic sensitivity analyses were conducted to assess uncertainty in results.

RESULTS

The rifaximin ± lactulose regimen provided added health benefits despite an additional cost versus lactulose monotherapy. Model results showed an incremental benefit of $29,161 per QALY gained and $27,762 per LY gained with rifaximin ± lactulose versus lactulose monotherapy. Probabilistic sensitivity analyses demonstrated that the rifaximin ± lactulose regimen was cost-effective ~99% of the time at a threshold of $50,000 per QALY/LY gained, which falls within the commonly accepted threshold for incremental cost-effectiveness.

CONCLUSIONS

The clinical benefit of rifaximin, combined with an acceptable economic profile, demonstrates the advantages of rifaximin maintenance therapy as an important option to consider for patients at risk of recurrent HE.

DISCLOSURES

This analysis was funded by Salix Pharmaceuticals, a division of Bausch Health US. Salix and Xcenda collaborated on the methods, and Salix, Xcenda, Jesudian, and Ahmad collaborated on the writing of the manuscript and interpretation of results. Bozkaya and Migliaccio-Walle are employees of Xcenda. Ahmad reports speaker fees from Salix Pharmaceuticals, unrelated to this study. Jesudian reports consulting and speaker fees from Salix Pharmaceuticals, unrelated to this study. The results from this model were presented at AASLD: The Liver Meeting 2014; November 7-11; Boston, MA.

The cost-effectiveness of disease-modifying therapies for the treatment of relapsing-remitting multiple sclerosis

BACKGROUND

The safety and efficacy of disease-modifying therapies (DMTs) for relapsing-remitting multiple sclerosis (RRMS) has been established; however, it is not clear which provides optimal value, given benefit-risk profiles and costs.

AIMS

To compare the cost-effectiveness of current DMTs for patients with RRMS in the US.

MATERIALS AND METHODS

A Markov model predicting RRMS course following initiation of a DMT was created comparing outcomes (e.g. relapses, disease progression) and costs of natalizumab (NTZ), dimethyl fumarate (DMF), and peginterferon beta-1a (PEG) with fingolimod (FIN), glatiramer acetate (GA, 20 mg daily), and subcutaneous interferon beta-1a (IFN, 44 mcg), respectively, over 10 years. RRMS and secondary-progressive MS (SPMS) EDSS state transitions were predicted in 3-month cycles in which patients were at risk of death, relapse, or discontinuation. Upon DMT discontinuation, natural history progression and relapse rates were applied. Incremental cost-effectiveness ratios (ICERs) were estimated for the cost per relapse avoided, relapse-free years gained, progression avoided, and progression-free years gained. The impact of model parameters on outcomes was evaluated via one-way sensitivity analyses.

RESULTS

Costs ranged from $561,177 (NTZ) to $616,251 (GA). NTZ, DMF, and PEG were dominant (less costly and more effective) compared to FIN, GA, and IFN, respectively, for all ICERs. Variability in drug costs and parameters that affected drug cost accrual (e.g. discontinuation rates and the decision to drop out after SPMS conversion) had a considerable impact on ICERs.

LIMITATIONS

Several simplifying assumptions were made that may represent potential limitations of this analysis (e.g. a constant treatment effect over time was assumed).

CONCLUSIONS

The results from this analysis suggest that the NTZ, DMF, and PEG are cost-effective DMT choices compared to FIN, GA, and IFN, respectively. The actual impact on a particular plan will vary based on drug pricing and other factors affecting drug cost accrual.

Estimating the Costs of Therapy in Patients with Relapsed and/or Refractory Multiple Myeloma: A Model Framework

BACKGROUND

Multiple myeloma is a progressive cancer for which there is no cure. Despite treatment, almost all patients eventually experience periods of disease relapse and remission. With the increasing use of novel therapies, including bortezomib, lenalidomide, carfilzomib, pomalidomide, and panobinostat, benchmarks for assessing the value of these therapies in treating patients with relapsed or refractory multiple myeloma (RRMM) are needed for physicians and payers alike.

OBJECTIVES

To develop a model framework and to calculate an annual estimate of the total costs per patient for the treatment of patients with RRMM using 7 common treatment regimens, including bortezomib plus dexamethasone; panobinostat, bortezomib, and dexamethasone; lenalidomide plus dexamethasone; lenalidomide, bortezomib, and dexamethasone; carfilzomib; carfilzomib, lenalidomide, and dexamethasone; and pomalidomide plus dexamethasone.

METHODS

The expenditures for drugs and their administration, for prophylaxis and adverse event monitoring, and for the treatment of grade 3 or 4 adverse events were included in the calculations of the total pharmacy and medical costs. The drug costs were based on published pricing and labeled dosing schedules; the adverse event prophylaxis and monitoring costs were obtained from peer-reviewed publications; and the adverse event incidence rates were obtained from each regimen's prescribing information and from clinical trials. All the costs were summed over the duration of therapy for which the drugs were administered and were calculated separately for commercial and Medicare plans. The duration of therapy for each regimen was the time for which a patient had to be receiving the regimen to obtain 12 months of progression-free survival based on the duration-of-therapy to progression-free survival ratio observed from published clinical trials and/or the drug's labeling.

RESULTS

The pharmacy costs were highest for pomalidomide plus dexamethasone, whereas the medical costs were highest for the combination of carfilzomib, lenalidomide, and dexamethasone. The total cost associated with available treatments for RRMM was highest for regimens that included lenalidomide (approximate range, $126,000-$256,000). Only bortezomib plus dexamethasone and the combination of panobinostat, bortezomib, and dexamethasone had total costs that were lower than $125,000 per patient.

CONCLUSION

This study represents the first model developed to comprehensively estimate the costs of managing RRMM with all currently approved and guideline-recommended regimens in the United States. As such, it provides the framework and basis for further budget impact analyses and for cost-effectiveness comparisons with these regimens.

Economic considerations for mid-urethral sling procedures among patients with stress urinary incontinence

OVERVIEW

Stress urinary incontinence (SUI) is associated with a hefty economic burden. Retropubic and transobturator vaginal slings have become common surgical options for women with SUI. This study examines the costs of transobturator slings for SUI surgeries.

METHODS

A model was created to estimate the budget impact to hospitals of transobturator sling surgery in women with SUI. Current practice using transobturator slings including the MonarcTM Subfascial Hammock, Obtryx® Transobturator Mid-Urethral Sling System, Aris® Transobturator Sling System, Align® TO Trans-Obturator Urethral Support System, GYNECARE TVTTM Obturator System Tension-free Support for Incontinence and GYNECARE TVT ABBREVOTM Continence System were modeled. Four surgical complications were considered: re-operation due to failure, revision or removal of sling, urologic complications including urinary obstruction and urinary tract infection, and pelvic complications. This model calculates the average 1-year cost per patient with the use of each sling product and estimates the total budget for sling urinary incontinence surgery associated with each product based on these calculations.

RESULTS

Average incremental cost over 1 year ranged from $2,601 (GYNECARE TVTTM Obturator) to $3,132 (Desara®) per patient. In a hypothetical population of 100 patients, a 10% shift from the most to the least expensive option was associated with a 2% decrease in hospital expenditures. With the current market share for transobturator sling products, the expected expenditure is around $285,533 for a surgical population of 100 patients. Sling costs account for approximately $105,526 (37%) of this cost, with complications comprising the remaining majority.

CONCLUSION

This study represents the first comparative assessment of the costs of different sling options for stress urinary incontinence surgeries. GYNECARE TVT ABBREVOTM and GYNECARE TVTTM Obturator products represent a sound clinical and economic choice for hospitals. Moreover, the reduction in expenditures is obtained at the benefit of patients, who experience fewer complications and avoid complication-related procedures.

Long-term patterns of use and treatment failure with anticholinergic agents for overactive bladder

BACKGROUND

Overactive bladder (OAB) involves a complex set of symptoms with a lifetime prevalence of any symptom in ~30% of women and 20% of men. Anticholinergic agents are associated with poor medication persistence in OAB treatment.

OBJECTIVE

This study evaluated the long-term patterns of use and treatment failure in patients prescribed anticholinergic agents for OAB.

METHODS

This was a nonexperimental, retrospective cohort study. Medical, pharmacy, and eligibility data from the IMS LifeLink Health Plans Claims Database were used. Men and women aged ≥18 years were eligible for inclusion with an International Classification of Diseases, Ninth Revision, Clinical Modification, diagnosis of OAB in any field during the patient study period from January 2005 to June 2010. First documentation of a prescription filled between July 2005 and June 2008 for an anticholinergic agent was defined as the index prescription. Other inclusion criteria were: ≥1 pharmacy claim for an anticholinergic drug between July 2005 and June 2008; continuous enrollment 6 months before the index date, during which no anticholinergic drugs were filled; and 24 months of follow-up from the index prescription. Study outcomes were treatment failure, discontinuation, switch, reinitiation, and adherence. Treatment failure was defined as having a treatment discontinuation (ie, treatment gap of ≥45 days) or switching anticholinergic therapy.

RESULTS

The analytic cohort comprised 103,250 patients with a mean age of 58.7 years. A majority were female (73%) and privately insured (75%). The vast majority of patients (91.7%) failed to meet their treatment goals with their index anticholinergic agent over the 24-month follow-up period. Of these, 5.8% switched, 51.3% permanently discontinued all anticholinergic agents, and 34.6% reinitiated treatment sometime after 45 days. The mean (SD) time to treatment failure was 159 (216.0) days, with a mean of 1.3 (0.5) unique anticholinergic agents per patient. Forty-eight percent of patients demonstrated appropriate adherence as determined by a medication possession ratio ≥80%.

CONCLUSIONS

This study provides real-world data on treatment patterns over 2 years in a large cohort of patients diagnosed with OAB. Despite the potential for better adherence with some anticholinergic agents, these analyses suggest that such benefits have not yet been realized, and many patients end up without effective pharmacotherapy. Thus, there is a need for new therapies and strategies to increase persistence and adherence to improve outcomes in OAB.

Lopinavir/ritonavir versus darunavir plus ritonavir for HIV infection: a cost-effectiveness analysis for the United States

BACKGROUND

The ARTEMIS trial compared first-line antiretroviral therapy (ART) with lopinavir/ritonavir (LPV/r) to darunavir plus ritonavir (DRV + RTV) for HIV-1-infected subjects. In order to fully assess the implications of this study, economic modelling extrapolating over a longer term is required.

OBJECTIVE

The aim of this study was to simulate the course of HIV and its management, including the multiple factors known to be of importance in ART.

METHODS

A comprehensive discrete event simulation was created to represent, as realistically as possible, ART management and HIV outcomes. The model was focused on patients for whom clinicians believed that LPV/r or DRV + RTV were good options as a first regimen. Prognosis was determined by the impact of initial treatment on baseline CD4+ T-cell count and viral load, adherence, virological suppression/failure/rebound, acquired resistance mutations, and ensuing treatment changes. Inputs were taken from trial data (ARTEMIS), literature and, where necessary, stated assumptions. Clinical measures included AIDS events, side effects, time on sequential therapies, cardiovascular events, and expected life-years lost as a result of HIV infection. The model underwent face, technical and partial predictive validation. Treatment-naive individuals similar to those in the ARTEMIS trial were modelled over a lifetime, and outcomes with first-line DRV + RTV were compared with those with LPV/r, both paired with tenofovir and emtricitabine. Up to three regimen changes were permitted. Drug prices were based on wholesale acquisition cost. Outcomes were lifetime healthcare costs (in 2011 US dollars) from the US healthcare system perspective and quality-adjusted life-years (QALYs) (discounted at 3 % per annum).

RESULTS

Choice of LPV/r over DRV + RTV as initial ART resulted in nearly identical clinical outcomes, but distinctly different economic consequences. Starting with an LPV/r regimen potentially results in approximately US$25,000 discounted lifetime savings. Accumulated QALYs for LPV/r and DRV + RTV were 12.130 and 12.083, respectively (a 19-day difference). In sensitivity analyses, net monetary benefit ranged from US$12,000 to US$31,000, favouring LPV/r (base case US$27,762).

CONCLUSIONS

A comprehensive simulation of lifetime course of HIV in the USA indicated that using LPV/r as first-line therapy compared with DRV + RTV may result in cost savings, with similar clinical outcomes.

Management options for children with attention-deficit/hyperactivity disorder: a regional perspective on value

Use of comparative effectiveness information in local healthcare decisions can be confounded by variations in practice, barriers to access and population demographics. The New England Comparative Effectiveness Public Advisory Council was convened as a public deliberative panel that considers evidence on the comparative clinical effectiveness and comparative value of a variety of therapeutic interventions. The council is tasked with making summary judgments on the evidence and recommendations for applying the evidence in medical and drug coverage policy, as well as initiating educational efforts for patients and clinicians. The New England Comparative Effectiveness Public Advisory Council met in June 2012 to discuss management options for attention-deficit/hyperactivity disorder, guided by a recent comparative effectiveness review from the Agency for Healthcare Research and Quality and supplementary economic analyses conducted by the Institute for Clinical and Economic Review. This article summarizes the deliberations and reflects on lessons learned regarding use of region-specific economic analyses to guide decision-making.

Evaluation of the consequences associated with diffuse vascular disease history in patients diagnosed with peripheral arterial disease: estimates from Saskatchewan health data

Background

Peripheral arterial disease (PAD) is caused by narrowing of the arteries in the lower extremities. Limited data exist concerning the impact of diffuse vascular disease (DVD) on prognosis and costs. Thus, the objective of this study is to estimate the impact of DVD on morbidity, mortality and costs.

Methods

PAD was identified between 1985 and 1995 and classified by extent of DVD at diagnosis: none (PAD only, reference group), prior myocardial infarction (MI), prior stroke, prior MI and stroke (MI + stroke), prior transient ischemic attack (TIA). Deaths and hospitalizations were identified through December 2000. Hospitalization costs were estimated from the Ontario Case Cost Project, reported in 2002 $CAD. Proportional hazards analyses measured the impact of vascular involvement on mortality while controlling for risk factors (e.g., age, cardiovascular history).

Results

Overall, 16,439 patients with PAD were included; 14.8% had a prior MI, 10.2% a prior stroke, 2.6% prior MI + stroke, 6.4% prior TIA, two-thirds had PAD only. Median survival was shorter for patients with prior MI (9.3 yrs), TIA (6.3), stroke (4.7), and MI+stroke (4.1) versus the reference group (9.9, p < 0.05, all comparisons). Analyses revealed that the death risk was 60% higher in patients with prior stroke and 84% higher for MI + stroke. Atherothrombotic and bleeding event-related costs were $712, $337, $268, and $170 higher per patient/year of follow-up in patients with a history of MI+stroke, MI, stroke, and TIA, respectively.

Conclusion

Patients diagnosed with PAD with DVD have higher risk of poor outcomes and increased costs.

Cost effectiveness of deferasirox compared to desferrioxamine in the treatment of iron overload in lower-risk, transfusion-dependent myelodysplastic syndrome patients

OBJECTIVE

The study evaluated the cost effectiveness of deferasirox (Exjade * ) compared to non-proprietary desferrioxamine (DFO) for the control of transfusional iron overload in lower risk myelodysplastic syndromes (MDS) patients. A UK National Health Service perspective was adopted.

METHODS

Recent clinical evidence has demonstrated the efficacy and safety of deferasirox in transfusion-dependent MDS patients with elevated serum ferritin levels. An economic model was used to extrapolate the clinical benefits of iron chelation therapy (ICT) in a cohort of lower risk MDS patients. Costs for drug acquisition, drug administration and monitoring, and quality of life (utility) outcomes associated with mode of drug administration were derived from a variety of sources. The incremental cost per QALY gained for deferasirox was estimated. Costs and outcomes were discounted at 3.5% in line with UK standards.

RESULTS

The base-case cost effectiveness of deferasirox versus DFO was estimated to be £20,822 per QALY gained, the key driver being the additional quality of life benefits associated with a simpler mode of administration for deferasirox. A mean survival benefit for both forms of ICT of 4.5 years was estimated. The results were sensitive to drug dose, days of DFO administration, and patient weight.

CONCLUSIONS

In the UK, a cost per QALY below £20,000-30,000 is considered cost effective. Hence, the results from this economic analysis suggest deferasirox is cost effective in lower risk, transfusion-dependent, MDS patients. Limitations with the analysis include a lack of comparative randomised controlled trial evidence, in particular to differentiate survival and clinical outcomes for deferasirox and DFO.

NICE cost-effectiveness appraisal of cholinesterase inhibitors: was the right question posed? Were the best tools used?

The National Institute for Health and Clinical Excellence (NICE) recently issued updated guidance on the use of cholinesterase inhibitors in the treatment of Alzheimer's disease. NICE initially recommended that cholinesterase inhibitors no longer be used, but final guidance restricted treatment to patients with disease of a moderately severe stage. This decision was based largely on results from a heavily criticised economic evaluation that used an adaptation of the Assessment of Health Economics in Alzheimer's Disease (AHEAD) model. As the developers of the AHEAD model, we examined the appropriateness of NICE's economic analyses and presentation of results. We attempted to replicate NICE's results by modifying the original AHEAD model. Sensitivity analyses were then run using the modified AHEAD model to evaluate the extent of uncertainty in predictions. The AHEAD(NICE) analyses resulted in an incremental cost-effectiveness ratio for galantamine of 82,000 pound per QALY gained (year 2003 values) from the perspective of the UK NHS and Personal Social Services. This was later revised to 46,000 pound per QALY, compared with < 9000 pound per discounted QALY gained (year 2001 values) in the original AHEAD model. Using our modified AHEAD with effectiveness estimates matching those of AHEAD(NICE), we show that NICE's choice and presentation of sensitivity analyses obscured the instability of their estimates. In the final NICE evaluation, the recommendation to delay treatment with cholinesterase inhibitors until patients have moderately severe disease was based on critical assumptions in the economic analyses that had little evidence to support them. The case of NICE's guidance on cholinesterase inhibitors highlights the importance of transparent and valid economic evaluations and the dangers of using inappropriate modelling technologies, basing analyses on a limited subset of the available data, and insufficiently reflecting the uncertainty in estimates that are intended to inform decision makers.

Economic implications of growth hormone use in patients with short bowel syndrome

OBJECTIVE

Short bowel syndrome is a rare, life-threatening condition that can result in nutritional malabsorption. Parenteral nutrition provides life-saving support but can lead to complications and affect quality of life. Recombinant human growth hormone, somatropin (rDNA origin), has been shown to significantly reduce dependence on nutritional support (p < 0.05). This study evaluates the economic impact of somatropin use in the management of short bowel syndrome.

METHODS

A discrete event simulation (DES) model was developed to estimate the benefits and costs associated with somatropin use. Risks of treatment complications and of disease-related events were modeled in identical patient pairs--one receiving parenteral nutrition alone, the other receiving 4 weeks of somatropin--for 2 years following initiation of treatment. Life expectancy was assumed equivalent. Risk functions were estimated from the literature and one randomized clinical trial. Total and component costs associated with each strategy were determined. The distribution of patients reducing parenteral nutrition need and the final parenteral nutrition frequency were also estimated. Sensitivity analyses were completed for key inputs. Direct medical costs are reported in US 2004 dollars.

RESULTS

The model predicted that 96.0% of patients receiving somatropin reduce or eliminate parenteral nutrition within 6 weeks: average use was reduced by 2.8 days and one-third weaned completely. Based on 1.9 L of parenteral nutrition per day, estimated costs were 118,098 dollars in year one and 132,935 dollars in year two. With somatropin, costs dropped to 84,309 dollars in year one--despite the 17,459 dollars cost of somatropin treatment--and 81,250 dollars in year two. Over 2 years savings totaled 85,474 dollars.

LIMITATIONS

Insufficient data required that assumptions be made for some inputs. DES is new in pharmacoeconomics and may be perceived as a limitation.

CONCLUSIONS

Somatropin use improves quality of life by reducing the need for parenteral nutrition and results in health care cost savings.

The time course of subsequent hospitalizations and associated costs in survivors of an ischemic stroke in Canada

Background

Documentation of the hospitalizations rates following a stroke provides the inputs required for planning health services and to evaluate the economic efficiency of any new therapies.

Methods

Hospitalization rates by cause were examined using administrative data on 18,695 patients diagnosed with ischemic stroke (first or subsequent, excluding transient ischemic attack) in Saskatchewan, Canada between 1990 and 1995. Medical history was available retrospectively to January 1980 and follow-up was complete to March 2000. Analyses evaluated the rate and timing of all-cause and cardiovascular hospitalizations within discrete periods in the five years following the index stroke. Cardiovascular hospitalizations included patients with a primary diagnosis of ischemic stroke, transient ischemic attack, myocardial infarction, stable or unstable angina, heart failure or peripheral arterial disease.

Results

One-third (36%) of patients were identified by a hospitalized stroke. Mean age was 70.5 years, 48.0% were male, half had a history of stroke or a transient ischemic attack at the time of their index stroke. Three-quarters of the patients (72.7%) were hospitalized at least once during a mean follow-up of 4.6 years, accruing CAD $24 million in the first year alone. Of all hospitalizations, 20.4% were related to cardiovascular disease and 1.6% to bleeds. In the month following index stroke, 12.5% were admitted, an average of 1.04 times per patient hospitalized. Strokes accounted for 33% of all hospitalizations in the first month. The rate diminished steadily throughout the year and stabilized in the second year when approximately one-third of patients required hospitalization, at a rate of about one hospitalization for every two patient-years. Mean lengths of stay ranged from nine days to nearly 40 days. Close-fitting Weibull functions allow highly specific probability estimates. Other cardiovascular risk factors significantly increased hospitalization rates.

Conclusion

After stroke, there are frequent hospitalizations accounting for substantial additional costs. Though these rates drop after one year, they remain high over time. The number of other cardiovascular causes of hospitalization confirms that stroke is a manifestation of disseminated atherothrombotic disease.

The morbidity and mortality following a diagnosis of peripheral arterial disease: long-term follow-up of a large database

BACKGROUND

Awareness of the significance of peripheral arterial disease is increasing, but quantitative estimates of the ensuing burden and the impact of other risk factors remains limited. The objective of this study was to fill this need.

METHODS

Morbidity and mortality were examined in 16,440 index patients diagnosed with peripheral arterial disease in Saskatchewan, Canada between 1985 and 1995. Medical history and patient characteristics were available retrospectively to January 1980 and follow-up was complete to March 1998. Crude and adjusted event rates were calculated and Kaplan-Meier survival curves estimated. Cox proportional hazards analyses were conducted to examine the effect of risk factors on these rates. Patients suffering a myocardial infarction or ischemic stroke in Saskatchewan provided two reference populations.

RESULTS

Half of the index patients were male; the majority was over age 65; 73% had at least one additional risk factor at index diagnosis; 10% suffered a subsequent stroke, another 10% a myocardial infarction, and 49% died within the mean follow-up of 5.9 years. Annual mortality (8.2%) was higher among patients with PAD than after a myocardial infarction (6.3%) but slightly lower than that in patients suffering a stroke (11.3%). Index patients with comorbid disease (e.g., diabetes) were at highest risk of death and other events.

CONCLUSION

A diagnosis of peripheral arterial disease is critical evidence of more widespread atherothrombotic disease, with substantial risks of subsequent cardiovascular events and death. Given that the majority has additional comorbidities, these risks are further increased.

Assessing the health and economic impact of galantamine treatment in patients with Alzheimer's disease in the health care systems of different countries

INTRODUCTION

Cholinesterase inhibitors have been shown to improve cognitive function and improve or maintain global function.

OBJECTIVE

To estimate the long-term economic impact of treating patients with Alzheimer's disease with galantamine in seven healthcare systems: Australia, Canada, Finland, New Zealand, Sweden, the Netherlands and the UK.

METHODS

The time until patients require full-time care (FTC), defined as the consistent requirement for a significant amount of care giving and supervision each day, and the associated costs were evaluated using the 'Assessment of Health Economics in Alzheimer's Disease (AHEAD)' model. Efficacy data were obtained from three clinical trials comparing galantamine with placebo and local cost and resource use data were determined for each country. Forecast costs reported in Euros (2001 value), were made for up to 10 years in each healthcare system. All costs were determined from a perspective somewhat broader than that of a comprehensive payer, including social services. Both benefits and costs were discounted at 3%.

RESULTS

Galantamine (16 mg/day) is predicted to delay the need for FTC by 6.8%, thus the cumulative cost of care over 10 years is expected to be reduced, and this offsets much or all of the cost of galantamine. Approximately five patients need to be treated to avoid 1 year of FTC. In each healthcare system, FTC was estimated to account for 61-92% of the cost. Savings were estimated for most of the countries. For those countries with an expected expense, there were reasonable costs per FTC month avoided (euro553, discounted) and costs per quality-adjusted life year gained (euro25,000).

CONCLUSION

In addition to the clinical benefits associated with galantamine treatment, the savings predicted from delaying FTC may offset the treatment costs.

Costs and medical care consequences associated with the diagnosis of peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) is increasingly recognised as an indicator of disseminated atherothrombosis, but its impact on use of healthcare resources is not well understood.

OBJECTIVE

To provide a quantitative description of the resource utilisation and costs incurred following PAD.

METHODS

Hospitalisations, physician visits and the corresponding direct medical costs were examined in 16,440 patients with a diagnosis of PAD (1985--1995) in Saskatchewan, Canada, and compared with 15,590 reference patients with a diagnosis of myocardial infarction (MI) [1990--1995]. Medical history and patient characteristics were available retrospectively to January 1980 and follow-up to December 2000. Rates and timing of all-cause and cardiovascular hospitalisations and physician visits within discrete periods in the 10 years following PAD diagnosis, and 5 years following MI, were evaluated, as were lengths of stay and predictors of hospitalisation.

RESULTS

Average follow-up was 5.9 years among patients with PAD and 3.6 years for MI. Half (55%) of patients with PAD were male versus 64% of reference patients. The mean ages were 67.3 and 66.9 years, respectively. Patients with PAD were hospitalised most frequently soon after diagnosis, with rates subsequently decreasing to 0.14 per month. These rates were similar in the reference group except for the period immediately following MI. The average 5-year cost post-diagnosis (2002 Can dollars) per patient was 41,968 Can dollars vs 48,578 Can dollars for the reference population.

CONCLUSIONS

A diagnosis of PAD not only imposes a severe burden on patients and their families, but it also significantly increases the use of healthcare resources and the associated costs. By the end of year 1, this burden is comparable with a diagnosis of MI.

Estimating survival for cost-effectiveness analyses: a case study in atherothrombosis

BACKGROUND

Economic evaluations typically require estimates of survival beyond the limited follow-up in clinical trials. The objective of this study was to demonstrate a data-driven approach to deriving these estimates.

METHODS

To provide survival estimates for analyses of the CAPRIE trial, data were obtained from Saskatchewan on more than 50,000 patients like those in the trial: diagnosed with peripheral arterial disease (PAD), myocardial infarction, or ischemic stroke between 1985 and 1995; follow-up to December 31, 2000. Mean survival was estimated by integrating the full survival curve derived by applying hazard functions over time. Cox proportional hazards analyses were carried out in each of four periods defined to ensure proportionality.

RESULTS

Adjusting for mean age in CAPRIE, mean survival ranged from 12.1 years after index stroke to 13.6 years after diagnosis of PAD. Comorbidities reduced mean survival by 1 to 2 years. Subsequent events had a marked detrimental effect, decreasing life-expectancy by 50% or more, and disease in multiple vascular beds led to survival of less than 5 years.

DISCUSSION

These analyses demonstrate the analytic methods required to accurately estimate survival. The trial ages were much lower than in the observational study. Thus, the estimates are optimistic for the general population.

CONCLUSIONS

Accurate valuation of interventions depends on valid survival estimates. These analyses confirm that survival is significantly reduced in patients with atherothrombotic disease, particularly with additional comorbidities.

Comparing medications in a therapeutic area using an NNT model

OBJECTIVES

Clinicians are told to use the number needed to treat (NNT) to compare the benefits of therapeutic strategies, and researchers are asked to report results this way, generally without considering differences among the studies from which these were derived.

METHODS

The crude NNT currently advocated is compared to the NNT standardized for a common outcome, follow-up time, study population and comparator. An NNT model for cardiovascular disease is described as an example that addresses differences among studies of secondary prevention of cardiovascular disease. Crude NNTs are compared to those obtained from the model.

RESULTS

Follow-up in the 18 trials identified varied from 1.0 to 6.2 years; rates of cardiovascular events in the untreated subgroups ranged from 4.8% to 45.9%. The crude NNTs were more variable (9.1-163.7) than those obtained from the model (9.1-75.2). The effect of standardization was substantial in some cases, with proportional changes ranging from a 91% decrease to a 223% increase.

CONCLUSION

Using an NNT model to account for differences in study design allows for more meaningful comparisons.

Rational choice of cholinesterase inhibitor for the treatment of Alzheimer's disease in Canada: a comparative economic analysis

BACKGROUND

Cholinesterase inhibitors, such as galantamine, donepezil and rivastigmine are approved for symptomatic treatment of Alzheimer's Disease (AD) in Canada. In making choices amongst these drugs, one should consider their clinical merits and their economic implications.

METHODS

Each drug's short-term efficacy was estimated based on independent Cochrane reviews of the clinical trials. Long-term clinical and economic outcomes were estimated using the Assessment of Health Economics in Alzheimer's Disease (AHEAD) model.

RESULTS

While all treatments reduced the need for full-time care, only galantamine and donepezil 10 mg reduced the overall management costs of AD patients. The somewhat greater cognitive effect provided over six months by galantamine leads to the longest estimated delay before full-time care is required and, consequently to lower overall costs, with savings estimated at between 323 dollars and 4,246 dollars.

CONCLUSION

Although there is uncertainty in estimated results, the best information currently available suggests that the first choice for treatment of AD should be galantamine. These results should be interpreted with caution, however, as results are not based on direct comparisons among the drugs and the differences emerging from meta-analyses of the trials are relatively small.

Economic evaluation of galantamine in the treatment of mild to moderate Alzheimer's disease in the United States

BACKGROUND

Alzheimer's disease (AD) is estimated to affect up to 11% of those aged > or =65 years in the United States, and the number of patients with AD is predicted to increase over the next few decades as the population ages. The substantial social and economic burden associated with AD is well established, with the cost of management increasing as the disease progresses.

OBJECTIVE

The aim of this study was to evaluate the economic impact of galantamine 16 and 24 mg/d relative to no pharmacologic treatment in the management of mild to moderate AD in the United States based on the concept of need for full-time care (FTC).

METHODS

Calculations were made using the Assessment of Health Economics in Alzheimer's Disease model, which applies predictive equations to estimate the need for FTC and the associated costs. The predictive equations were developed from longitudinal data on patients with AD. Inputs to the equations were derived by analyzing the data from 2 randomized, placebo-controlled, galantamine clinical trials. Resource use (from a payer perspective) was estimated from US clinical trial data, and costs were estimated from several US databases. Analyses were carried out over 10 years, and costs and benefits were discounted at 3%.

RESULTS

In the base case, 3.9 to 4.6 patients need to start treatment with galantamine to avoid 1 year of FTC, depending on dose. Treated patients spent 7% to 8% more time pre-FTC and 12% to 14% less time requiring FTC, resulting in savings of 2408 to 3601 US dollars. Time horizons below 3 years, very high discontinuation rates, or increased survival with galantamine reversed the savings. Conversely, limiting treatment to responders delayed FTC by 6 to 7 months, with savings of approximately 9097 to 11,578 US dollars.

CONCLUSIONS

These results suggest that use of galantamine in patients with AD in the United States could reduce the use of costly resources such as formal home care and nursing homes, leading to cost savings over time.

To what degree does cognitive impairment in Alzheimer's disease predict dependence of patients on caregivers?

BACKGROUND

Patients with Alzheimer's disease experience a progressive loss of cognitive function, and the ability to independently perform activities of daily life. Sometimes a dependent stage is reached quite early in the disease, when caregivers decide that the patients can no longer be left alone safely. This is an important aspect of Alzheimer's for patients, their families, and also health care providers. Understanding the relationship between a patient's current cognitive status and their need for care may assist clinicians when recommending an appropriate management plan. In this study, we investigated the relationship of cognitive function to dependence on caregivers before the patients reach a severe stage of the disease.

METHODS

Data were obtained on 1,289 patients with mild-to-moderate Alzheimer's disease studied in two randomised clinical trials of galantamine (ReminylcircledR;). Cognition was assessed using the cognitive part of the Alzheimer's Disease Assessment Scale (ADAS-cog) and Mini-Mental State Examination (MMSE). Patients were considered dependent if they required >12 hours of supervision each day or had high care needs. The Disability Assessment for Dementia (DAD) scale was also used as a measure of dependence. Disability was predicted directly using MMSE and ADAS-cog and compared to predictions from converted scores.

RESULTS

The odds ratio of dependence was significantly higher amongst the patients with worse cognitive impairment, adjusting for age, gender and antipsychotic medication use. For example, a 4-point difference in ADAS-cog score was associated with an increase of 17% (95% CI 11-23) in the adjusted odds for >12 hours of supervision, and of 35% (95% CI 28-43) for dependence. Disability predicted directly using actual ADAS-cog and scores converted from MMSE values had close agreement using the models developed.

CONCLUSION

In patients with mild-to-moderate Alzheimer's disease, even relatively small degrees of poorer cognitive function increased the risk of losing the ability to live independently.

Assessment of health economics in Alzheimer's disease (AHEAD) based on need for full-time care

OBJECTIVE

To develop a framework for estimating the long-term health and economic consequences of AD based on patient characteristics at a given point in time.

METHODS

A pharmacoeconomic model (Assessment of Health Economics in Alzheimer's Disease, AHEAD) was developed based on equations that relate the probability of needing full-time care (FTC) over time to patient characteristics summarized in index scores. These equations were developed from published data on interquartile times until FTC is needed and until death, using nonlinear regressions of the resulting index-specific hazards. These equations were then incorporated into a hidden Markov framework that allows for calculation of expected time to FTC and to death, as well as of the economic consequences of disease progression. There are three major states in the model: not requiring FTC ("pre-FTC"), requiring FTC, and death.

RESULTS

Outcomes for five sample patients are derived to illustrate application of the AHEAD model. The impact of altering disease markers in these patients is also considered.

CONCLUSION

The need for a generally applicable tool to forecast long-term outcomes based on relatively short-term data is becoming increasingly acute with the advent of new therapies for AD. The AHEAD model provides a relatively simple framework for the prediction of time to FTC requirement based on short-term observed data such as those from clinical trials. Although subject to the uncertainties inherent in modeling, the model nevertheless provides a standard estimation technique that may facilitate comparisons between existing and emerging therapies.

Economic analysis of initial HIV treatment. Efavirenz- versus indinavir-containing triple therapy

OBJECTIVE

To compare the clinical and economic outcomes associated with triple therapy containing efavirenz or indinavir and 2 nucleoside reverse transcriptase inhibitors (NRTIs; zidovudine and lamivudine) in HIV-positive patients.

DESIGN AND SETTING

An economic model based on viral load and CD4+ cell counts to predict long term outcomes such as progression to AIDS and AIDS-related death was developed and then analysed using data from a randomised clinical trial. Cost estimates from the healthcare system perspective were based on data from 6 state, all-payor databases, the AIDS Cost and Services Utilisation Study, and other literature. Analyses were carried out for time horizons between 5 and 15 years.

PATIENTS AND INTERVENTIONS

HIV-positive patients with limited exposure to NRTIs. Initial regimens consisted of efavirenz or indinavir, each combined with 2 NRTIs. A maximum of 2 switches to other regimens was permitted.

MAIN OUTCOME MEASURES AND RESULTS

The efavirenz-containing triple therapy regimen was predicted to prolong survival at a savings of up to 10,923 US dollars (1998 values) relative to initial therapy with the indinavir-containing regimen. Patients who receive efavirenz are expected to have 11% greater survival at 5 years and fewer treatment failures (28 vs 52%, at 2 years). Overall, the economic and health benefits predicted for the efavirenz-containing regimen were robust to reasonable variation in key parameters.

CONCLUSIONS

The superior clinical trial outcomes for efavirenz-containing regimens should translate into substantial economic and health benefits.

Generalizing the results of clinical trials to actual practice: the example of clopidogrel therapy for the prevention of vascular events. CAPRA (CAPRIE Actual Practice Rates Analysis) Study Group. Clopidogrel versus Aspirin in Patients at Risk of Ischaemic Events

PURPOSE

An important element in translating the results obtained in clinical trials of a new treatment to clinical practice is the estimated event rate in patients who would be eligible to receive that treatment. We estimated the effect of clopidogrel, compared with aspirin, in actual practice using the relative risk reduction observed in the Clopidogrel versus Aspirin in Patients at Risk of Ischaemic Events (CAPRIE) trial.

SUBJECTS AND METHODS

Ischemic event rates were estimated for 12,931 aspirin users drawn from the Saskatchewan Health population between 1990 and 1995 who had an index diagnosis of myocardial infarction, ischemic stroke, or peripheral arterial disease. To estimate the absolute risk reduction, the 8.7% relative risk reduction from clopidogrel compared with aspirin that was observed in CAPRIE was applied to these rates.

RESULTS

The rates of ischemic events were greater in actual practice than among the control patients in the CAPRIE trial. In the Saskatchewan population, patients experienced an outcome event (myocardial infarction, stroke including intracranial hemorrhage, or death) at a rate of 15.9 per 100 patient-years, compared with only 6.9 per 100 patient-years in CAPRIE. If the same 8.7% relative risk reduction seen in the CAPRIE trial is also true for patients seen in routine clinical practice, the greater absolute risk in actual practice would reduce the number needed to treat to prevent one event from 200 patients to 70 patients.

CONCLUSION

Absolute risk rates may be substantially greater in clinical practice than in the selected patients enrolled in randomized trials. As a result, similar reductions in relative risk, if true for clinical practice, may yield substantially more benefit in clinical practice than in randomized trials.

Anticoagulant prophylaxis against stroke in atrial fibrillation: effectiveness in actual practice

BACKGROUND

Randomized trials have shown a beneficial effect of anticoagulation with warfarin to prevent stroke in atrial fibrillation. It is not known whether the same effect will be obtained in actual practice. The authors conducted a prospective observational study to evaluate the effect of preventive anticoagulation in patients with atrial fibrillation in 2 practice settings in Montreal.

METHODS

Of the 1725 outpatients screened between October 1990 and September 1993 at a community hospital and a university-affiliated hospital, 221 with documented atrial fibrillation were enrolled and followed up for a mean of 27 months. Most (75%) of the patients excluded did not meet the inclusion criteria (because of, for example, an artificial heart valve, mitral stenosis, cardiac transplantation or transient atrial fibrillation); the remainder had not completed enrollment before the end of the study. Following the baseline visit, patients were interviewed by telephone every 6 months, and reported events were confirmed through review of the patients' charts. Hazards for stroke and for stroke and transient ischemic attack (TIA) combined were calculated for each of 4 treatment groups: ASA, warfarin, blended treatment and no treatment, based on the type of anticoagulation therapy patients received during the entire observation period. The blended-treatment group consisted of patients who started on one active therapy and switched to the other or who switched treatments more than once. Corresponding rate ratios (RRs) and 95% confidence intervals (CIs) were calculated with reference to the no-treatment group. Cox proportional hazards analysis was used to adjust for differences in patient characteristics. The rates of bleeding episodes were also analysed.

RESULTS

On average, the study patients were older (71.6 [standard deviation 9.3] years) and had a higher prevalence of underlying heart disease (52.0%) than those in the randomized trials. Nineteen patients had a first stroke: 4 in the ASA group, 4 in the warfarin group, 4 in the blended-treatment group and 7 in the no-treatment group, for rates of 5.2, 1.8, 5.3 and 5.9 per 100 person-years, respectively. Only warfarin was associated with a significantly lower risk of stroke compared with no anticoagulant therapy (RR 0.31, 95% CI 0.09-1.00). A similar protective effect of warfarin was found for stroke and TIA combined (2.3 v. 6.7 per 100 person-years; RR 0.34, 95% CI 0.12-0.99); the effect of ASA and blended treatment was not significantly different from no treatment. The rate per 100 person-years of any bleeding was not significantly higher for any treatment group (ASA 2.5, warfarin 3.4 and blended treatment 3.5) compared with the no-treatment group (1.9). Patients receiving warfarin had a significantly greater risk of any bleeding event than patients not receiving anticoagulant therapy (RR 1.79, 95% CI 1.07-3.00).

INTERPRETATION

The relative effect of anticoagulant therapy with warfarin in preventing stroke in these practice settings was equivalent to that in the randomized trials, although these patients were older and sicker. This preventive treatment is likely to confer additional benefit as it is more widely prescribed.

The cost of treating heart valve related complications

BACKGROUND AND AIM OF THE STUDY

Heart valve replacement can result in serious complications. Therefore, it is important in decision making regarding the choice of valves to know the cost of such complications.

METHODS

Complications were defined according to guidelines proposed by the Society of Thoracic Surgeons. They included valve thrombosis, embolism, hemorrhage due to anticoagulation, non-structural dysfunction, structural deterioration and endocarditis. The costs of the pre-admission assessment, acute inpatient stay, inpatient physician fees, post-discharge and out-patient physician fees were estimated for each complication to determine the average total cost in 1995 US dollars. Cost inputs were obtained from existing Massachusetts databases and Medicare fee schedules.

RESULTS

The costs of managing valve thrombosis, endocarditis and non-structural dysfunction were all estimated to exceed $30,000 for a single event. The costs of acute management of embolism and anticoagulant-related hemorrhage were between $8,000 and $11,500. However, it is of note that managing the sequelae of an embolism was calculated to be greater than $70,000 over 15 years. The greatest contributor to the average cost of treating a complication was determined to be the in-patient facility cost.

CONCLUSIONS

Complications related to heart valve replacement can be very costly to manage in both the short term and the long term.

Bileaflet valve replacement: complications and costs

A meta-analysis of the available literature on the CarboMedics and St. Jude Medical valves was conducted to compare their clinical performance. Frequency of valve-related complications for aortic, mitral, and double-valve replacements served as a measure of performance. An economic model was created to estimate the economic impact of valve-related complications. Overall, fewer events occurred with the St. Jude Medical valve than with the CarboMedics valve. As a result, use of the St. Jude Medical valve is expected to save up to $13,201 over 10 years.