Publications (14)28.94 Total impact
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Article: Lopinavir/Ritonavir Versus Darunavir Plus Ritonavir for HIV Infection: A Cost-Effectiveness Analysis for the United States.
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ABSTRACT: 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.PharmacoEconomics 04/2013; · 2.66 Impact Factor -
Article: Evaluation of the consequences associated with diffuse vascular disease history in patients diagnosed with peripheral arterial disease: estimates from Saskatchewan health data.
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ABSTRACT: 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. 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). 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. Patients diagnosed with PAD with DVD have higher risk of poor outcomes and increased costs.BMC Cardiovascular Disorders 01/2010; 10:40. · 1.52 Impact Factor -
Article: NICE cost-effectiveness appraisal of cholinesterase inhibitors: was the right question posed? Were the best tools used?
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ABSTRACT: 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.PharmacoEconomics 01/2007; 25(12):997-1006. · 2.66 Impact Factor -
Article: Economic implications of growth hormone use in patients with short bowel syndrome.
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ABSTRACT: 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. 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. 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. Insufficient data required that assumptions be made for some inputs. DES is new in pharmacoeconomics and may be perceived as a limitation. Somatropin use improves quality of life by reducing the need for parenteral nutrition and results in health care cost savings.Current Medical Research and Opinion 10/2006; 22(10):2055-63. · 2.38 Impact Factor -
Article: The time course of subsequent hospitalizations and associated costs in survivors of an ischemic stroke in Canada.
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ABSTRACT: 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. 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. 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. 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.BMC Health Services Research 02/2006; 6:99. · 1.66 Impact Factor -
Article: The morbidity and mortality following a diagnosis of peripheral arterial disease: long-term follow-up of a large database.
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ABSTRACT: 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. 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. 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. 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.BMC Cardiovascular Disorders 02/2005; 5:14. · 1.52 Impact Factor -
Article: Costs and medical care consequences associated with the diagnosis of peripheral arterial disease.
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ABSTRACT: 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. To provide a quantitative description of the resource utilisation and costs incurred following PAD. 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. 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. 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.PharmacoEconomics 02/2005; 23(7):733-42. · 2.66 Impact Factor -
Article: The morbidity and mortality following a diagnosis of peripheral arterial disease: Long-term follow-up of a large database
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ABSTRACT: Abstract 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.BMC Cardiovascular Disorders. 01/2005; -
Article: Assessing the health and economic impact of galantamine treatment in patients with Alzheimer's disease in the health care systems of different countries.
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ABSTRACT: Cholinesterase inhibitors have been shown to improve cognitive function and improve or maintain global function. 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. 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%. 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). In addition to the clinical benefits associated with galantamine treatment, the savings predicted from delaying FTC may offset the treatment costs.Drugs & Aging 02/2004; 21(10):677-86. · 2.67 Impact Factor -
Article: Rational choice of cholinesterase inhibitor for the treatment of Alzheimer's disease in Canada: a comparative economic analysis.
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ABSTRACT: 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. 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. 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. 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.BMC Geriatrics 01/2004; 3:6. · 2.34 Impact Factor -
Article: Economic evaluation of galantamine in the treatment of mild to moderate Alzheimer's disease in the United States.
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ABSTRACT: 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. 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). 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%. 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. 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.Clinical Therapeutics 06/2003; 25(6):1806-25. · 2.32 Impact Factor -
Article: To what degree does cognitive impairment in Alzheimer's disease predict dependence of patients on caregivers?
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ABSTRACT: 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. 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. 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. 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.BMC Neurology 08/2002; 2:6. · 2.17 Impact Factor -
Article: Comparing medications in a therapeutic area using an NNT model.
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ABSTRACT: 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. 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. 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. Using an NNT model to account for differences in study design allows for more meaningful comparisons.Value in Health 7(5):585-94. · 2.19 Impact Factor -
Article: Estimating survival for cost-effectiveness analyses: a case study in atherothrombosis.
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ABSTRACT: 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. 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. 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. 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. 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.Value in Health 7(5):627-35. · 2.19 Impact Factor
Top co-authors
Top Journals
- Value in Health (2)
- PharmacoEconomics (2)
- BMC Cardiovascular Disorders (2)
- Clinical Therapeutics (1)
- Drugs & Aging (1)
Institutions
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2010
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United BioSource Corporation
Chevy Chase, MD, USA
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2005
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Boston Biomedical Research Institute
Boston, MA, USA
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