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Quantification of small stream contributions to global carbon cycling is key to understanding how freshwater systems transmit and transform carbon between terrestrial and atmospheric pools. To date, greenhouse gas emissions of carbon dioxide and methane from freshwaters, particularly in mountainous regions, remain poorly characterized due to a lack of direct field observations. Using a unique longitudinal approach, we conducted field surveys across two ecoregions (Middle Rockies and Great Plains) in the Clear Creek watershed, a subwatershed of Wyoming's Powder River Basin. We took direct measurements of stream gases using headspace sampling at 30 sites (8 June to 23 October). We observed the lowest and most variable concentrations in headwaters, which flow through a federally designated alpine wilderness area. By contrast, the Great Plains exhibited 1.45 and 4 times higher pCO2 and pCH4 concentrations and the relative contributions of methane increased downstream. Fluxes during snowmelt were 45% and 58% higher for CO2 and CH4 than during base flow but overall were lower than estimates for other systems. Variability for pCO2 was highest during late summer and in the uppermost sections of the headwaters. The high heterogeneity and common undersaturation observed through space and time, especially in the mountains, suggest that downscaled regional estimates may fail to capture variability in fluxes observed at these smaller scales. Based on these results, we strongly recommend higher resolution time series studies and increased scrutiny of systems at near equilibrium, inclusive of winter storage and ice-off events, to improve our understanding of the effects of seasonal dynamics on these processes. [ABSTRACT FROM AUTHOR]

The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well as the overwhelming effect of humans across most of the world. Based on our projected tree densities, we estimate that over 15 billion trees are cut down each year, and the global number of trees has fallen by approximately 46% since the start of human civilization. [ABSTRACT FROM AUTHOR]

Background: The optimal BMI threshold above which gastric bypass surgery should be offered to obese patients is controversial. The objective of this study was to compare the impact of Roux-en-Y gastric bypass (RYGB) vs. diet and exercise (D&E) on life expectancy to find the BMI at which patients experience an improvement in their life expectancy by undergoing surgery. Methods: A Markov state transition model was designed to implement a decision tree that simulated the lives of obese patients. Life expectancies following RYGB and 2 years of D&E were estimated and compared. Ten thousand patients' lives were simulated in each weight-loss intervention group in the model. In addition to base case analysis (45 kg/m BMI pre-intervention), sensitivity analysis of initial BMI at the start of the study was completed. Markov model parameters were extracted from the literature. Results: The impact of RYGB on survival relative to D&E depended on the patient's initial BMI. Compared to patients who underwent 2 years of 'optimal' diet and exercise (7 % total body weight loss/year), RYGB improved long-term survival for patients above a BMI of 31.3 kg/m. Conclusions: Roux-en-Y gastric bypass can improve long-term survival for patients with class I obesity. This study suggests that RYGB should not be reserved solely for patients with class II or III obesity. [ABSTRACT FROM AUTHOR]

Background:Data on the cost-effectiveness of the behavioral treatment of obesity are not conclusive. The cost-effectiveness of treatment in primary care settings is particularly relevant.Methods:We conducted a within-trial cost-effectiveness analysis of a primary care-based obesity intervention. Study participants were randomized to: Usual Care (UC; quarterly visits with their primary care provider); Brief Lifestyle Counseling (BLC; quarterly provider visits plus monthly weight loss counseling visits) or Enhanced Brief Lifestyle Counseling (EBLC; all above interventions, plus choice of meal replacements or weight loss medication). A health-care payer perspective was used. Intervention costs were estimated from tracking data obtained prospectively. Quality-adjusted life years (QALYs) were estimated with the EuroQol-5D. We estimated cost per kilogram-year of weight loss and cost per QALY.Results:Weight losses after 2 years were 1.7, 2.9 and 4.6 kg for UC, BLC and EBLC, respectively (P=0.003 for comparison of EBLC vs UC). The incremental cost per kilogram-year lost was $292 for EBLC compared with UC (95% confidence interval (CI): $219-$437). The short-term incremental cost per QALY was $115 397, but the 95% CI were undefined. Comparison of short-term cost per kg with published estimates of longer-term cost per QALY suggested that the intervention could be cost-effective over the long term (10 years).Conclusions:A primary care intervention that includes monthly counseling visits and a choice of meal replacements or weight loss medication could be a cost-effective treatment for obesity over the long term. However, additional studies are needed on the cost-effectiveness of behavioral treatment of obesity. [ABSTRACT FROM AUTHOR]

To estimate per-person and aggregate direct medical costs of overweight and obesity and to examine the effect of study design factors. PubMed (1968-2009), EconLit (1969-2009) and Business Source Premier (1995-2009) were searched for original studies. Results were standardized to compute the incremental cost per overweight person and per obese person, and to compute the national aggregate cost. A total of 33 US studies met review criteria. Among the four highest-quality studies, the 2008 per-person direct medical cost of overweight was $266 and of obesity was $1723. The aggregate national cost of overweight and obesity combined was $113.9 billion. Study design factors that affected cost estimates included use of national samples vs. more selected populations, age groups examined, inclusion of all medical costs vs. obesity-related costs only, and body mass index cut-offs for defining overweight and obesity. Depending on the source of total national healthcare expenditures used, the direct medical cost of overweight and obesity combined is approximately 5.0% to 10% of US healthcare spending. Future studies should include nationally representative samples, evaluate adults of all ages, report all medical costs and use standard body mass index cut-offs. [ABSTRACT FROM AUTHOR]

Alcohol treatment services are increasingly combined with other health and social services to address the needs of multiple-problem clients. Hence, it has been of growing policy interest to find the most effective and the most cost-effective ways of linking these services. This symposium presents some recent studies in this area. The small but growing body of studies in this area has great potential to inform public policy debates. [ABSTRACT FROM AUTHOR]

We performed an economic analysis of data from 180 women in a clinical trial of conventional-dose chemotherapy vs high-dose chemotherapy plus stem-cell transplantation for metastatic breast cancer responding to first-line chemotherapy. Data on resource use, including hospitalizations, medical procedures, medications, and diagnostic tests, were abstracted from subjects' clinical trial records. Resources were valued using the Medicare Fee Schedule for inpatient costs at one academic medical center and average wholesale prices for medications. Monthly costs were calculated and stratified by treatment group and clinical phase. Mean follow-up was 690 days in the transplantation group and 758 days in the conventional-dose chemotherapy group. Subjects in the transplantation group were hospitalized for more days (28.6 vs 17.8, P=0.0041) and incurred higher costs ($84?055 vs $28?169) than subjects receiving conventional-dose chemotherapy, with a mean difference of $55 886 (95% CI, $47?298-$63?666). Sensitivity analyses resulted in cost differences between the treatment groups from $36?528 to $75?531. High-dose chemotherapy plus stem-cell transplantation resulted in substantial additional morbidity and costs at no improvement in survival. Neither the survival results nor the economic findings support the use of this procedure outside of the clinical trial setting.Bone Marrow Transplantation (2003) 31, 205-210. doi:10.1038/sj.bmt.1703795 [ABSTRACT FROM AUTHOR]

Little research has been conducted towards the development and evaluation of a measure of quality of life specific to head/brain injury populations. Accordingly, we examined responses to the Neurobehavioral Functioning Inventory in the context of a clinical trial for head injury patients (n=655) conducted in 14 countries. To reduce the 66 item scale into a smaller number of composite scales, principal components analysis was conducted. Scales were constructed assessing four categories of symptoms: cognitive deficits, depression, aggression and somatization. The internal reliabilities (a coefficient) of the four scales were generally acceptable (range=0.79–0.92). Scores on all four scales correlated significantly with patient-rated overall quality of life and all but the aggression scale correlated significantly with overall clinical severity. The need for more formal evaluation of this and other disease-specific measures is discussed. [ABSTRACT FROM AUTHOR]

Our objective was to assess the economic impact of a new cytokine therapy that was being compared to standard therapy as supportive care in patients receiving autologous bone marrow transplantation for treatment of lymphoma. We performed an economic study accompanying a multicenter, randomized, controlled clinical trial in academic medical centers. One hundred and fifteen patients consented to participate in a parallel economic study of a randomized controlled trial of sequential IL-3 followed by GM-CSF vs GM-CSF alone after autologous bone marrow transplantation. We measured costs and quality-adjusted survival over a 13-month follow-up period. For the 13-month study period, the total cost estimates were $79892 (95% CI $69343 to $90544) for patients receiving GM-CSF alone and $89651 (95% CI $79769 to $102114) for patients receiving IL-3/GM-CSF. The difference was not statistically significant. During the 13-month study period, the total number of quality-adjusted life-months in the GM-CSF arm was 6.67 (95% CI 5.75 to 7.56) months, while the total number of quality-adjusted life-months in the IL-3 arm was 6.26 (95% CI 5.34 to 7.15) months. The difference in quality-adjusted life-months between the two treatment arms was not statistically significant. We conclude that economic analysis of a phase III clinical trial of IL-3/GM-CSF compared with GM-CSF alone showed no significant effect of IL-3 on the costs of care for patients undergoing bone marrow transplantation for a period of up to 13 months after the procedure. This study demonstrates the feasibility of prospective economic evaluation within phase III trials of new cancer therapies. Data from this type of economic protocol could be used to help physicians, patients and managed care organizations understand the effect of new treatments from both a clinical and an economic perspective. [ABSTRACT FROM AUTHOR]

Objective: Comparison of four measures of cholesterol for predicting men and women who will develop coronary heart disease within 8 to 10 years.Design: Cohort study.Patients: 1898 men who received placebo (the placebo group of the Lipid Research Clinics [LRC] Coronary Primary Prevention Trial [CPPT]), 1025 men and 1442 women who participated in the 1970-1971 Framingham Heart Study biennial examination, and 1911 men and 1767 women without coronary heart disease who were from the LRC Population Prevalence Study.Measurements: Total cholesterol, low-density lipoprotein (LDL) cholesterol, ratio of total cholesterol to high-density lipoprotein (HDL) cholesterol, and the ratio of LDL to HDL. Outcomes were coronary heart disease in the CPPT and Framingham studies and death from coronary heart disease in the Prevalence Study.Results: Independent information in the total cholesterol/HDL ratio added risk-discriminating ability to total cholesterol and LDL cholesterol measures (P < 0.02), but the reverse was not true. Among women, a high-risk threshold of 5.6 for the total cholesterol/HDL ratio identified a 0% to 15% larger group at 25% to 45% greater risk in the Prevalence and Framingham studies, respectively, than did current guidelines. Among men in the same studies, a risk threshold of 6.4 for the total cholesterol/HDL ratio identified a 69% to 95% larger group at 2% to 14% greater risk than did LDL cholesterol levels alone. Eight-year likelihood ratios for coronary heart disease ranged from 0.32 to 3.11 in men and from 0.59 to 2.98 in women for total cholesterol/HDL ratios (grouped from < 3 to > or = 9).Conclusions: The total cholesterol/HDL ratio is a superior measure of risk for coronary heart disease compared with either total cholesterol or LDL cholesterol levels. Current practice guidelines could be more efficient if risk stratification was based on this ratio rather than primarily on the LDL cholesterol level. [ABSTRACT FROM AUTHOR]

We did a cost-effectiveness analysis of zidovudine therapy for asymptomatic patients with human immunodeficiency virus (HIV) infection. The incremental direct medical costs of zidovudine therapy were determined, and data on the effects of therapy were derived from the report of the Acquired Immunodeficiency Syndrome (AIDS) Clinical Trials Group Protocol 019. Zidovudine therapy has an annual incremental cost of $2653 per person. The cost per year of life saved ranges between $6553 and $70 526, depending on which epidemiologic model of potential long-term zidovudine effect is used (in sensitivity analyses, the cost per year of life saved ranges between $2649 and $250 546). Although expensive, zidovudine therapy has the potential to yield a substantial survival benefit to patients. The cost effectiveness of zidovudine therapy compares favorably with that of other common medical therapies. [ABSTRACT FROM AUTHOR]

The main objective of this study was to elicit proportional cause specific mortality in the underfives in the urban slums of Lucknow in North India. The families with under five mortality in the 28 randomly selected slums in 1993 were located from the records of the slum health workers and verbal autopsy was conducted to assign a cause of death. There were 71 deaths among 2796 children. The annual under five mortality was 25.4 and the under five mortality rate was 126.7. After the neonatal period, "high fever" that could not be classified into any other disease incorporated in the verbal autopsy instrument, was the most common symptom associated with death, seen in 21.1% cases (95% C.I.: 15.5-34.4%) followed by these diseases: pneumonia in 19.7%, diarrhea in 18.3% and measles in 11.4%. "High fever" as the leading symptom associated with death is being reported for the first time from the urban slums of India. There is an urgent need to identify the underlying etiologies of death due to "high fever" and the policy implications are that children with fever must receive immediate and continued medical attention till the symptom persists. [ABSTRACT FROM AUTHOR]

Objective: To assess the cost-effectiveness of the HA-1A monoclonal antibody for the treatment of gram-negative bacteremia.Design: Cost-effectiveness analysis of a randomized, double-blind, placebo-controlled trial using clinical efficacy data reported in the medical literature.Setting: Hospitalized patients with sepsis.Patients: 543 patients with sepsis and suspected gram-negative infection. Patients enrolled in the study met strict criteria for sepsis, including fever or hypothermia (less than 35.6 degrees C or greater than 38.3 degrees C), tachycardia (greater than 90 beats per minute), tachypnea (greater than 20 breaths per minute), and hypotension or two of six signs of systemic toxicity.Intervention: HA-1A vs placebo in addition to usual care.Main Outcome Measures: We determined the range of possible cost-effectiveness ratios for HA-1A therapy, using modeling techniques when clinical or economic variables were unknown. We subjected the model to rigorous sensitivity analysis. We calculated the incremental cost of care and years of life saved for patients with sepsis and modeled two different treatment strategies: treat all patients with sepsis or test and then treat only patients with positive test results. $24,100 per year of life saved based on the treat strategy and $14,900 based on the test strategy. In sensitivity analysis the ratios ranged from $5200 to $110,200 per year of life gained. Annual costs of care for these two strategies are $1.3 billion for the test strategy and $2.3 billion for the treat strategy.Conclusion: Economic assessment of new technologies early in their development can be used to guide their efficient clinical introduction. [ABSTRACT FROM AUTHOR]

We performed a cost-effectiveness analysis of pharmacologic treatment of high blood cholesterol levels. Agents modeled were cholestyramine, colestipol, gemfibrozil, lovastatin, niacin, and probucol. Pharmacologic effectiveness was estimated from reported studies. Cost estimates reflect societal resource consumption. Annual costs for therapy ranged from $327 (niacin) to $1881 (lovastatin, 80 mg/d). Niacin was the most efficient agent for reducing low-density lipoprotein cholesterol levels, having an average cost over 5 years of $139 per percent reduction in low-density lipoprotein cholesterol level. Lovastatin (20 mg/d) was also efficient ($177 per percent reduction). Cholestyramine was least efficient at $347. For high-density lipoprotein cholesterol, niacin was most efficient, at $116 per percent increase in high-density lipoprotein cholesterol level, followed by gemfibrozil at $271. Analyses combining low-density lipoprotein cholesterol and high-density lipoprotein cholesterol effects suggest that niacin and lovastatin (20 mg/d) were most efficient for reducing cardiovascular risk. [ABSTRACT FROM AUTHOR]

Hospitals' patterns of ancillary service use were examined to determine whether new technologies replace older, more outmoded technologies, and to explore the factors associated with adoption of newer services and abandonment of older services. Annual inpatient use of five pairs of ancillary services was measured for 1978 through 1980 at 63 hospitals in five regions. The diagnostic test pairs consisted of one well-established diagnostic test and one newer service that could largely substitute for the older one and included (1) oral cholecystogram and gallbladder ultrasound; (2) brain scan and computed tomographic head scan; (3) skull roentgenogram and brain scan; (4) bone survey and bone scan; and (5) blood type/cross and type/screen. Use of gallbladder ultrasound increased significantly after its adoption, with small decreases in the use of oral cholecystogram, its paired test. For the other newer tests examined, increased use was not accompanied by significantly decreased use of the paired older service. The strongest predictors of change in patterns of test use were hospital size, number of residencies, occupancy, urban location, and the proportion of specialists on staff. We conclude that diffusion of new diagnostic services occurs gradually and often without concomitant decrease in older, outmoded services; new services generally seem to complement rather than substitute for older ones. Larger hospitals with a greater teaching commitment make a faster transition to the use of new technologies and the abandonment of older ones. [ABSTRACT FROM AUTHOR]