Organs for transplantation are scarce, but new medical therapies can prevent organ failure and th... more Organs for transplantation are scarce, but new medical therapies can prevent organ failure and the need for transplants. We sought to describe the unique value created by treatments that spare organs from failure and thus conserve donated organs for transplant into others, using hepatitis C virus (HCV) as a case study. Epidemiologic-economic model. Using data on trends in chronic liver disease, liver disease progression, and liver transplant allocation models, as well as the effectiveness of new HCV treatments, we estimate the potential effects of systematic HCV screening and treatment on the demand for liver transplants in the United States. We estimate the spillover benefits to patients with all-cause liver disease in terms of increased availability of transplants and life-years gained. We estimated that systematic HCV screening and treatment could spare 10,490 liver transplants to HCV-infected patients from 2015 to 2035. An estimated 7321 transplants would accrue to patients with...
Malaria is responsible for an estimated one million deaths per year, the vast majority in sub-Sah... more Malaria is responsible for an estimated one million deaths per year, the vast majority in sub-Saharan Africa. Many of these deaths are attributed to delays in seeking treatment and poor adherence to drug regimes. While there are a growing number of studies describing the factors influencing treatment seeking for malaria, far less is known about the relative weight given to these factors in different settings. This study estimates two models of demand for malaria treatment in the Farafenni region of The Gambia. The first examines the determinants of seeking malaria treatment outside the home versus no treatment or self-care while the second identifies the determinants of provider choice conditional on having decided to seek malaria treatment outside the home. Providers included hospital; health centre; and 'other' which included pharmacies, kiosks; petty traders; neighbours; and traditional healers. Results show that older people were more likely to opt for self-care, or no treatment. The longer the time spent ill or the more severe the fever, the more likely a treatment was sought outside the home. Time of the year and availability of community infrastructure played a key role in both models. Poorer households and those from the Fula ethnic group were much more likely to visit an 'other' provider than a hospital. The policy and methodological implications of these findings are discussed.
Objective Preeclampsia is one of the top six causes of maternal mortality in the United States (U... more Objective Preeclampsia is one of the top six causes of maternal mortality in the United States (US) and is associated with considerable perinatal morbidity and mortality. Evidence suggests the US incidence of preeclampsia has increased dramatically over the past two decades. This study aims to compile, summarize, and critique the literature on the health and economic burden of preeclampsia and early-onset preeclampsia. Study Design We reviewed the literature for estimates of burden of preeclampsia and early-onset preeclampsia to both mother and child, summarized the evidence on economic and social burden, and highlighted current gaps in the literature. Results No recent studies comprehensively assess the costs and health consequences of preeclampsia or early-onset preeclampsia for both mother and child. Where it exists, the literature suggests preeclampsia and early-onset preeclampsia cause numerous adverse health consequences, but these conditions currently lack effective treatment...
The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease, 2005
An urban tuberculosis (TB) clinic, The Gambia. To identify patient characteristics associated wit... more An urban tuberculosis (TB) clinic, The Gambia. To identify patient characteristics associated with increased rates of defaulting from treatment, specifically knowledge and cost factors amenable to intervention. Prospective cohort study of TB cases at least 15 years of age commencing treatment, interviewed by semi-structured questionnaire and followed for attendance at thrice-weekly directly observed treatment (DOT). Of 301 patients, 76 (25.2%) defaulted from treatment and 25 did not return for treatment. The defaulting rate was higher among those who said they were uncertain that their treatment would work (HR 3.64; 95%CI 1.42-9.31, P = 0.007) and among those who incurred significant time or money costs travelling to receive treatment (HR 2.67; 95%CI 1.05-6.81; P = 0.04). These factors had differing effects with respect to time: uncertainty over treatment success was important in the first 90 days of treatment, while increased cost of travelling to the clinic was important after 90 ...
Journal of pediatric gastroenterology and nutrition, 2006
Central adiposity, a component of insulin resistance syndrome, is a risk factor for nonalcoholic ... more Central adiposity, a component of insulin resistance syndrome, is a risk factor for nonalcoholic fatty liver disease (NAFLD) in adults. To determine whether a similar relationship occurs in children, hepatic fat content and adipose tissue distribution were assessed in obese children at risk for NAFLD. We reviewed the charts of obese children undergoing evaluation for NAFLD because of hepatomegaly or elevated serum alanine aminotransferase (ALT) without obvious etiology. Hepatic fat fraction and adipose tissue distribution were obtained by rapid magnetic resonance imaging (MRI) techniques. Hepatic fat content was determined by a modification of the Dixon method that involves fast gradient echo. Body fat distribution was assessed by using heavily T1-weighted fast gradient echo technique on a single slice at the level of the umbilicus, and regions of interest were demarcated based upon pixel intensity threshold value including visceral adipose tissue (VAT) and subcutaneous adipose tiss...
The American journal of tropical medicine and hygiene, 2007
Malaria is still one of the biggest health threats in the developing world, with an estimated 300... more Malaria is still one of the biggest health threats in the developing world, with an estimated 300 million episodes per year and one million deaths, most of which are in sub-Saharan Africa. Although the efficacy and cost-effectiveness of treated bed nets has been widely reported, little is known about the range, strength, or interaction between different factors that influence their demand at the household level. This study modeled the determinants of bed net ownership as well as the factors that influence the number of bed nets purchased. Data was collected from 1,700 randomly selected households in the Farafenni region of The Gambia. Interviews were also held with 129 community spokespersons to explore the extent to which community level factors such as the quality of roads and access to market centers also influence demand for bed nets. The results of each model of demand and their policy implications are discussed.
To evaluate a health and fitness programme conducted within a New South Wales, Australia correcti... more To evaluate a health and fitness programme conducted within a New South Wales, Australia correctional facility for male inmates with a chronic illness. A randomised control trial. Twenty male inmate participants with a chronic illness, two risk factors for developing a chronic illness or who were over the age of 40 years. Pre and post programme health assessments that included resting blood pressure and heart rate, weight, body mass index, waist girth, peak flow measures, peripheral saturation of oxygen, blood glucose levels and 6 minute walk test. A 12-week structured exercise programme focusing on cardio respiratory endurance, strength and flexibility training. Statistically significant improvements in resting heart rate and endurance were found. The health and fitness programme positively impacts on the health of inmates with a chronic illness. A further study with a larger sample size would be productive.
ABSTRACT Background: Increasingly sedentary lifestyles and dietary changes associated with econom... more ABSTRACT Background: Increasingly sedentary lifestyles and dietary changes associated with economic development in China, combined with progress in the treatment of infectious disease have resulted in a shift in the disease burden - the so-called epidemiological transition. Cardiovascular disease (CVD), including coronary heart disease (CHD) and other non-communicable diseases now play an increasingly important role in the disease burden faced by China. However, little is known about the future burden of CHD morbidity and mortality, as well as the cost-effectiveness of particular CHD-prevention policies in China. Objectives: To estimate the impact of aging and epidemiological transition on the burden of CHD morbidity and mortality over the next 15 years in China and to estimate the net value of effective lipid management. Methods: First, we estimate the prevalence of CHD and other risk factors based on the China Health and Nutrition Survey. Next, using prediction from the literature regarding trends in demographic and cardiovascular risk factors, such as elevated low-density lipoprotein cholesterol (LDL-C), we model how CHD risk will evolve between 2015 and 2030. We then estimate how expanded use of statins for lipid management over the next 15 years would alter the prevalence of elevated LDL-C as a risk factor, and determine how this would dampen the future growth in CHD burden. Accounting for the costs of statin use, we assess the net value of a policy that expands statin utilization for lipid management in China. Results: We find that - left unchecked - rising prevalence of CHD risk factors and the aging of the Chinese population will lead to the incidence of heart attacks rising from 4 million in 2015 to over 6 million in 2030. Similarly, the number of CHD deaths will rise from 1.3 million in 2015 to over 2 million in 2030. Treating all hyperlipidemia patients with statins would avert 10.5 million heart attacks and 3.5 million CHD deaths between 2015 and 2030. Based on current estimates of treatment costs in China and the cost of statins, we predict that such a policy would produce a net social value of $176 to $226 billion over the next 15 years. Conclusions: In light of its aging population and continued economic development, China faces near-certain increases in the incidence of CHD morbidity and mortality. Preventative measures such as effective lipid management may reduce the CVD burden substantially and also provide large social value to the society. At a time when the Chinese government is taking steps towards a more systematic approach to health care delivery, primary and secondary prevention of CVD should be high on the agenda.
Organs for transplantation are scarce, but new medical therapies can prevent organ failure and th... more Organs for transplantation are scarce, but new medical therapies can prevent organ failure and the need for transplants. We sought to describe the unique value created by treatments that spare organs from failure and thus conserve donated organs for transplant into others, using hepatitis C virus (HCV) as a case study. Epidemiologic-economic model. Using data on trends in chronic liver disease, liver disease progression, and liver transplant allocation models, as well as the effectiveness of new HCV treatments, we estimate the potential effects of systematic HCV screening and treatment on the demand for liver transplants in the United States. We estimate the spillover benefits to patients with all-cause liver disease in terms of increased availability of transplants and life-years gained. We estimated that systematic HCV screening and treatment could spare 10,490 liver transplants to HCV-infected patients from 2015 to 2035. An estimated 7321 transplants would accrue to patients with...
Malaria is responsible for an estimated one million deaths per year, the vast majority in sub-Sah... more Malaria is responsible for an estimated one million deaths per year, the vast majority in sub-Saharan Africa. Many of these deaths are attributed to delays in seeking treatment and poor adherence to drug regimes. While there are a growing number of studies describing the factors influencing treatment seeking for malaria, far less is known about the relative weight given to these factors in different settings. This study estimates two models of demand for malaria treatment in the Farafenni region of The Gambia. The first examines the determinants of seeking malaria treatment outside the home versus no treatment or self-care while the second identifies the determinants of provider choice conditional on having decided to seek malaria treatment outside the home. Providers included hospital; health centre; and 'other' which included pharmacies, kiosks; petty traders; neighbours; and traditional healers. Results show that older people were more likely to opt for self-care, or no treatment. The longer the time spent ill or the more severe the fever, the more likely a treatment was sought outside the home. Time of the year and availability of community infrastructure played a key role in both models. Poorer households and those from the Fula ethnic group were much more likely to visit an 'other' provider than a hospital. The policy and methodological implications of these findings are discussed.
Objective Preeclampsia is one of the top six causes of maternal mortality in the United States (U... more Objective Preeclampsia is one of the top six causes of maternal mortality in the United States (US) and is associated with considerable perinatal morbidity and mortality. Evidence suggests the US incidence of preeclampsia has increased dramatically over the past two decades. This study aims to compile, summarize, and critique the literature on the health and economic burden of preeclampsia and early-onset preeclampsia. Study Design We reviewed the literature for estimates of burden of preeclampsia and early-onset preeclampsia to both mother and child, summarized the evidence on economic and social burden, and highlighted current gaps in the literature. Results No recent studies comprehensively assess the costs and health consequences of preeclampsia or early-onset preeclampsia for both mother and child. Where it exists, the literature suggests preeclampsia and early-onset preeclampsia cause numerous adverse health consequences, but these conditions currently lack effective treatment...
The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease, 2005
An urban tuberculosis (TB) clinic, The Gambia. To identify patient characteristics associated wit... more An urban tuberculosis (TB) clinic, The Gambia. To identify patient characteristics associated with increased rates of defaulting from treatment, specifically knowledge and cost factors amenable to intervention. Prospective cohort study of TB cases at least 15 years of age commencing treatment, interviewed by semi-structured questionnaire and followed for attendance at thrice-weekly directly observed treatment (DOT). Of 301 patients, 76 (25.2%) defaulted from treatment and 25 did not return for treatment. The defaulting rate was higher among those who said they were uncertain that their treatment would work (HR 3.64; 95%CI 1.42-9.31, P = 0.007) and among those who incurred significant time or money costs travelling to receive treatment (HR 2.67; 95%CI 1.05-6.81; P = 0.04). These factors had differing effects with respect to time: uncertainty over treatment success was important in the first 90 days of treatment, while increased cost of travelling to the clinic was important after 90 ...
Journal of pediatric gastroenterology and nutrition, 2006
Central adiposity, a component of insulin resistance syndrome, is a risk factor for nonalcoholic ... more Central adiposity, a component of insulin resistance syndrome, is a risk factor for nonalcoholic fatty liver disease (NAFLD) in adults. To determine whether a similar relationship occurs in children, hepatic fat content and adipose tissue distribution were assessed in obese children at risk for NAFLD. We reviewed the charts of obese children undergoing evaluation for NAFLD because of hepatomegaly or elevated serum alanine aminotransferase (ALT) without obvious etiology. Hepatic fat fraction and adipose tissue distribution were obtained by rapid magnetic resonance imaging (MRI) techniques. Hepatic fat content was determined by a modification of the Dixon method that involves fast gradient echo. Body fat distribution was assessed by using heavily T1-weighted fast gradient echo technique on a single slice at the level of the umbilicus, and regions of interest were demarcated based upon pixel intensity threshold value including visceral adipose tissue (VAT) and subcutaneous adipose tiss...
The American journal of tropical medicine and hygiene, 2007
Malaria is still one of the biggest health threats in the developing world, with an estimated 300... more Malaria is still one of the biggest health threats in the developing world, with an estimated 300 million episodes per year and one million deaths, most of which are in sub-Saharan Africa. Although the efficacy and cost-effectiveness of treated bed nets has been widely reported, little is known about the range, strength, or interaction between different factors that influence their demand at the household level. This study modeled the determinants of bed net ownership as well as the factors that influence the number of bed nets purchased. Data was collected from 1,700 randomly selected households in the Farafenni region of The Gambia. Interviews were also held with 129 community spokespersons to explore the extent to which community level factors such as the quality of roads and access to market centers also influence demand for bed nets. The results of each model of demand and their policy implications are discussed.
To evaluate a health and fitness programme conducted within a New South Wales, Australia correcti... more To evaluate a health and fitness programme conducted within a New South Wales, Australia correctional facility for male inmates with a chronic illness. A randomised control trial. Twenty male inmate participants with a chronic illness, two risk factors for developing a chronic illness or who were over the age of 40 years. Pre and post programme health assessments that included resting blood pressure and heart rate, weight, body mass index, waist girth, peak flow measures, peripheral saturation of oxygen, blood glucose levels and 6 minute walk test. A 12-week structured exercise programme focusing on cardio respiratory endurance, strength and flexibility training. Statistically significant improvements in resting heart rate and endurance were found. The health and fitness programme positively impacts on the health of inmates with a chronic illness. A further study with a larger sample size would be productive.
ABSTRACT Background: Increasingly sedentary lifestyles and dietary changes associated with econom... more ABSTRACT Background: Increasingly sedentary lifestyles and dietary changes associated with economic development in China, combined with progress in the treatment of infectious disease have resulted in a shift in the disease burden - the so-called epidemiological transition. Cardiovascular disease (CVD), including coronary heart disease (CHD) and other non-communicable diseases now play an increasingly important role in the disease burden faced by China. However, little is known about the future burden of CHD morbidity and mortality, as well as the cost-effectiveness of particular CHD-prevention policies in China. Objectives: To estimate the impact of aging and epidemiological transition on the burden of CHD morbidity and mortality over the next 15 years in China and to estimate the net value of effective lipid management. Methods: First, we estimate the prevalence of CHD and other risk factors based on the China Health and Nutrition Survey. Next, using prediction from the literature regarding trends in demographic and cardiovascular risk factors, such as elevated low-density lipoprotein cholesterol (LDL-C), we model how CHD risk will evolve between 2015 and 2030. We then estimate how expanded use of statins for lipid management over the next 15 years would alter the prevalence of elevated LDL-C as a risk factor, and determine how this would dampen the future growth in CHD burden. Accounting for the costs of statin use, we assess the net value of a policy that expands statin utilization for lipid management in China. Results: We find that - left unchecked - rising prevalence of CHD risk factors and the aging of the Chinese population will lead to the incidence of heart attacks rising from 4 million in 2015 to over 6 million in 2030. Similarly, the number of CHD deaths will rise from 1.3 million in 2015 to over 2 million in 2030. Treating all hyperlipidemia patients with statins would avert 10.5 million heart attacks and 3.5 million CHD deaths between 2015 and 2030. Based on current estimates of treatment costs in China and the cost of statins, we predict that such a policy would produce a net social value of $176 to $226 billion over the next 15 years. Conclusions: In light of its aging population and continued economic development, China faces near-certain increases in the incidence of CHD morbidity and mortality. Preventative measures such as effective lipid management may reduce the CVD burden substantially and also provide large social value to the society. At a time when the Chinese government is taking steps towards a more systematic approach to health care delivery, primary and secondary prevention of CVD should be high on the agenda.
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Papers by Warren Stevens