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At least 433 records · Page 24Linked to original sources
PubMed2004

[Study on the application of benchmark dose and biological monitoring indexes of fluorides in drinking water].

OBJECTIVE: By using Benchmark Dose (BMD) approach to explore the relations among drinking water fluoride, urine fluoride, serum fluoride and dental fluorosis; and to evaluate the significance of urine fluoride and serum fluoride in control and prevention of endemic fluorosis. METHODS: 512 children (290 in Xinhuai Village, 222 in Wamiao Village) aged 8-13 years were recruited in the study. Epidemiological methods were used to investigate the prevalence of dental fluorosis, and the levels of urine fluoride, serum fluoride, and drinking water fluoride in superficial well. The children were divided into six subgroups by the concentration of fluoride in drinking water: < 0.5 mg/L, 0.5-mg/L, 1.0-mg/L, 2.0-mg/L, 3.0-mg/L and > or = 4.0 mg/L. RESULTS: There was significant dose-response relationship between the drinking water fluoride and the prevalence of dental fluorosis or the prevalence of defect dental fluorosis. The BMDLs (Benchmark Dose Lower Bound) were 1.01 and 1.30 mg/L, respectively. Urine fluoride and serum fluoride also had significant dose-response relationship to the prevalence of dental fluorosis or defect dental fluorosis. The correlation coefficient between drinking water fluoride and urine fluoride was 0.717, and it was 0.855 between drinking water fluoride and serum fluoride, and 0.617 between urine fluoride and serum fluoride. CONCLUSIONS: The currently national standard of fluoride in drinking water in China is safe and reasonable. As a biological monitoring index, the levels of fluoride in serum may be more useful than that in urine in the control and prevention of endemic fluorosis.

Adolescent↗
PubMed2005

[Application of benchmark dose on occupational epidemiology research in lead exposure].

OBJECTIVE: To use the data of occupational epidemiology to estimate the benchmark dose (BMD) of renal dysfunction induced by lead. METHODS: Blood lead was considered as an exposure biomarker, while urinary total protein (TP), urinary beta(2)-microglobulin (beta(2)-MG) and urinary N-Acetyl-beta-D-glucosaminidase (NAG) were considered as effect biomarkers reflecting the damage of renal function. The dichotomized (binary) data was used as effect endpoints. The BMD and BMD lower limit (BMDL) of blood lead were estimated at the 10% benchmark response using BMDS version 1.3.1. RESULTS: There was an increased prevalence of hyper-TP-uria, hyper-beta(2)-MG-uria and hyper-NAG-uria with an increasing blood lead concentration. There was obviously dose-response relationship between blood lead and TP, beta(2)-MG and NAG, respectively. The BMD and BMDL of blood lead affecting renal function were estimated to be 323.6 - 754.3 microg/L and 274.2 - 541.5 microg/L. The BMDL of blood lead was ranged from low to high as NAG, TP and beta(2)-MG. The urinary NAG activity might be served as a sensitive biomarker in detecting early renal dysfunction. CONCLUSION: It should be feasible to use the BMD approach to set up the reference dose (RfD) and reference concentration (RfC). BMD approach might provide a new and better way for setting up the RfD/RfC.

Acetylglucosaminidase↗
PubMedDate not supplied

The HESI exit exam: Progression benchmark and remediation guide.

Evidence exists indicating that remediation positively affects NCLEX success of students with known academic deficits. However, specific benchmarks that identify students who are at risk of NCLEX failure and in need of remediation have not been identified. Following publication of research findings that established the reliability and validity of the HESI Exit Exam (E2) as an accurate measure of students' NCLEX preparedness, nurse educators increasingly chose to administer the E2 to their senior students. This study investigated using the E2 as a benchmark for progression and as a guide for remediation.

Journal Article↗
PubMed1984

Workers' compensation: 1976-80 benchmark revisions.

Because the two systems directly affect each other, the Social Security Administration (SSA) has had a long-standing interest in workers' compensation. In some cases, workers' compensation fills the gaps in protection not covered by Social Security and, in others, it may duplicate such protection. Since 1965, Social Security disability benefits have been subject to reduction if the beneficiary also receives workers' compensation and the combined benefits exceed 80 percent of previous earnings. SSA has also been directly involved in providing income maintenance for disability from work-related diseases since 1969, when the Federal Black Lung program was established. Every 4 years, SSA prepares a new set of benchmark figures to serve as a basis for its series on national workers' compensation benefits and program operations. The 1980 benchmark figures, presented here, provide an opportunity to review program operations during the decade of the 1970's.

Cost-Benefit Analysis↗
PubMedDate not supplied

Benchmarking surgeon satisfaction at academic health centers: a nationwide comparative survey.

BACKGROUND: Forty-six academic health centers (AHCs) belonging to the University HealthSystem consortium joined forces to compare the efficiency of their surgical services and to identify best practices. In addition to measures of operational performance, surgeon satisfaction with the surgical services provided was measured by using a standardized questionnaire. METHODS: From hospital records, indicators of the efficiency of surgical services were collected in three main areas: scheduling, preoperative testing and assessment, and the intraoperative process. Responding to a mail questionnaire, a sample of surgeons rated their satisfaction with key aspects of surgical services including scheduling, operating room staff, and equipment/supplies. On the basis of a review of the operational measures and the survey results, high performers were identified. Site visits were made to several of these high performers to uncover the critical factors responsible for their success. RESULTS: The survey revealed distinct variations in surgeon satisfaction across the participating institutions. Numerical benchmarks were obtained for surgeon satisfaction with each key component of surgical services. Scheduling was the most important component of overall surgeon satisfaction, explaining 71% of the variance in the rating of overall satisfaction with surgical services. High operational efficiency and high surgeon satisfaction were not incompatible. Several of the participating institutions were able to achieve both. These results were disseminated to all of the participants at a national meeting as well as in written form. CONCLUSIONS: The surgeon satisfaction survey allowed the participants to establish benchmarks for surgeon satisfaction for each key component of the surgical services they receive. The site visits revealed several common characteristics of highly efficient surgical services. Taken by themselves, the participating institutions might have been reluctant to consider adopting these best practices for fear of alienating the surgical staff. The availability of data on surgeon satisfaction showed the participants that these best practices can coexist with high levels of surgeon satisfaction. This has helped to promote their adoption by the other participating institutions.

Academic Medical Centers↗
PubMedDate not supplied

Benchmarking and clinical pathway implementation on a multihospital basis.

Hospital utilization data for communities with high levels of managed care penetration can be readily used to develop utilization benchmarks in any proactive efforts to prepare for oncoming prospective pricing system (PPS) initiatives. In a cooperative effort among all four Syracuse, NY hospitals, the combined average hospital LOS for one surgical and three medical DRGs was compared with benchmarks derived from similar populations in three heavily managed care-penetrated west coast communities. Implementation of clinical or critical paths are a widely accepted approach to shortening hospital lengths of stay and improving both resource usage and clinical outcomes. After implementing clinical paths across all four institutions and revisiting their data a year later, a fairly dramatic reduction (28%) in mean LOS for total hip replacement procedures was achieved. Two of the three medical DRGs, stroke and acute MI, each showed a mean reduction of 17% in LOS.

Critical Pathways↗
PubMed2026

Benchmarking of Reference-Based Tools for Strain-Level Resolution of Plant Microbiome.

Strain-level identification of each microbe is crucial for understanding its role in the host. Most of the existing tools have primarily been evaluated on human metagenomic datasets, whereas the plant microbiome exhibits greater diversity and complexity and thus poses a challenge in the strain-level resolution of individual microbes. In this study, we conducted a comprehensive benchmarking of available reference-based tools for strain-level resolution of the plant microbiome. We evaluated seven tools on various performance parameters, like computational requirements, F1-score and relative abundances using synthetic datasets comprising microbes known to have strong associations with plants as well as real plant microbiome datasets. Our results demonstrated a better performance of StrainScan on the synthetic data, achieving higher F1-score and more accurate relative abundance estimates as compared to other tools, but its performance declined gradually with increasing strain diversity. However, StrainGE and StrainScan exhibited competitive performance on real plant metagenome data. Overall, though StrainGE exhibited better performance, it was more computationally expensive. However, StrainScan performed better in detecting low-abundance strains. Our findings suggest the comparative suitability of the available tools for the strain-level analysis of plant metagenome data and highlight the need for the development of more efficient and accurate taxonomic classifiers capable of handling the complex plant metagenome data while maintaining computational efficiency.

Microbiota↗
PubMed2003

Cost-effectiveness of defunctioning stomas in low anterior resections for rectal cancer: a call for benchmarking.

HYPOTHESIS: Anastomotic leakage is the most important cost driver in patients who undergo low anterior resection (LAR) for rectal cancer. Creating defunctioning stomas to protect colorectal anastomoses may also have a major effect on the overall costs. Unselected creation of defunctioning stomas in most of these patients may be associated with higher overall costs compared with a program that has a low rate of defunctioning stomas and an acceptable anastomotic leakage rate. DESIGN: Cost-effectiveness analysis. SETTING: Secondary referral center. PATIENTS: Performing a cost analysis from the viewpoint of a hospital provider, we reviewed data of 70 consecutive patients who underwent LARs with (n = 19) or without (n = 51) a defunctioning colostomy. A scenario analysis was performed using data derived from the medical literature to assess a plausible range of leakage and stoma rates. MAIN OUTCOME MEASURE: Costs per treatment option and incremental cost-effectiveness ratio according to various treatment scenarios. RESULTS: Performing an LAR without a stoma and no anastomotic leakage is associated with significantly lowest costs (8.400 euro; P<.001) compared with patients with a stoma (13.985 euro) and patients with anastomotic leakage (42.250 euro). The most important cost drivers were anastomotic leakages and defunctioning stomas. A leakage rate of 16.5% in patients without a stoma would be necessary to balance the overall costs of patients with stomas. The incremental cost-effectiveness ratio would be 158.705 euro and 60.915 euro per leak, respectively, avoided in patients with defunctioning stomas assuming a leakage rate lower than 3% and 6%, respectively, in patients who did not undergo a colostomy. A 1-way sensitivity analysis revealed that duration and costs of intensive care unit care were the only factors that may considerably alter our results. CONCLUSIONS: A suggested benchmark for an LAR should be a rate of 10% or less for defunctioning stomas and anastomatic leaks; that would limit the overall costs to 12,000 euro per patient treated. Against the background of a lack of universally valid criteria for the creation of defunctioning stomas, our aim should be to reduce the rate of defunctioning stomas because of their major effect on the overall costs especially in programs with a lower leakage rate. Higher leakage rates despite higher stoma rates depend more on the skill of the surgeon than on the characteristics of the patient and higher leakage should lead to a change in surgical technique strategy.

Aged↗
PubMed2004

Normative values for the Health Assessment Questionnaire disability index: benchmarking disability in the general population.

OBJECTIVE: The Health Assessment Questionnaire (HAQ) disability index (DI) has been commonly used in rheumatology to quantify functional disability in patient groups, but current general population values of this index are not available. This study was undertaken to establish normative values for the HAQ DI in a general population and to analyze its correlates. METHODS: The HAQ DI (range of scores 0-3) was measured in a random sample of 1,530 adults in the Central Finland District. Prevalence rates of disability by strata of age, sex, education level, body mass index (BMI), and health behaviors (including smoking and exercise habits) were calculated. Pearson's product-moment correlation coefficient and ordinary least squares regression were used to analyze the data. RESULTS: The estimated population mean HAQ DI was 0.25 (95% confidence interval 0.22-0.28), and 32% of respondents had at least some disability. Both for men and for women, functional disability increased exponentially with age. The HAQ DI was correlated with pain (r = 0.58) and global self assessment (r = 0.61). The prevalence of disability decreased with increasing number of years of education, lower BMI, and increasing frequency of physical exercise. CONCLUSION: Almost one-third of the general population has some functional disability. Functional disability is associated in part with lifestyle choices and increases with age in a nonlinear manner. The normative values of the HAQ DI that we have presented could be used as a reference benchmark for clinical and epidemiologic studies using this measure of disability.

Adult↗
PubMed2005

An evaluation, comparison, and accurate benchmarking of several publicly available MS/MS search algorithms: sensitivity and specificity analysis.

MS/MS and associated database search algorithms are essential proteomic tools for identifying peptides. Due to their widespread use, it is now time to perform a systematic analysis of the various algorithms currently in use. Using blood specimens used in the HUPO Plasma Proteome Project, we have evaluated five search algorithms with respect to their sensitivity and specificity, and have also accurately benchmarked them based on specified false-positive (FP) rates. Spectrum Mill and SEQUEST performed well in terms of sensitivity, but were inferior to MASCOT, X!Tandem, and Sonar in terms of specificity. Overall, MASCOT, a probabilistic search algorithm, correctly identified most peptides based on a specified FP rate. The rescoring algorithm, PeptideProphet, enhanced the overall performance of the SEQUEST algorithm, as well as provided predictable FP error rates. Ideally, score thresholds should be calculated for each peptide spectrum or minimally, derived from a reversed-sequence search as demonstrated in this study based on a validated data set. The availability of open-source search algorithms, such as X!Tandem, makes it feasible to further improve the validation process (manual or automatic) on the basis of "consensus scoring", i.e., the use of multiple (at least two) search algorithms to reduce the number of FPs. complement.

Algorithms↗
PubMed1998

Regulatory cancer risk assessment based on a quick estimate of a benchmark dose derived from the maximum tolerated dose.

The proposed U.S. Environmental Protection Agency carcinogen risk assessment guidelines employ a benchmark dose as a point of departure (POD) for low-dose risk assessment. If information on the carcinogenic mode of action for a chemical supports a nonlinear dose-response curve below the POD, a margin-of-exposure ratio between the POD and anticipated human exposure would be considered. The POD would be divided by uncertainty (safety) factors to arrive at a reference dose that is likely to produce no, or at most negligible, cancer risk for humans. If nonlinearity below the POD is not supported by sufficient evidence, then linear extrapolation from the incidence at the POD to zero would be used for low-dose cancer risk estimation. The carcinogen guidelines suggest that the lower 95% confidence limit on the dose estimated to produce an excess of tumors in 10% of the animals (LTD10) be used for the POD. Due to the relatively narrow range of doses in 2-year rodent bioassays and the limited range of statistically significant tumor incidence rates, the estimate of the LTD10 obtained from 2-year bioassays is constrained to a relatively narrow range of values. Because of this constraint, a simple, quick, and relatively precise determination of the LTD10 can be obtained by the maximum tolerated dose (MTD) divided by 7. All that is needed is a 90-day study to establish the MTD. It is shown that the LTD10 determined by this relatively easy procedure is generally within a factor of 10 of the LTD10 that would be estimated using tumor incidence rates from 2-year bioassays. Estimates of cancer potency from replicated 2-year bioassays, and hence estimates of cancer risk, have been show to vary by a factor of 4 around a median value. Thus, there may be little gain in precision of cancer risk estimates derived from a 2-year bioassay, compared to the estimate based on the MTD from a 90-day study. If the anticipated human exposure were estimated to be small relative to the MTD/7 = LTD10, there may be little value in conducting a chronic 2-year study in rodents because the estimate of cancer risk would be low regardless of the results of a 2-year bioassay. Linear extrapolation to a risk of less than 1 in 100,000 and use of an uncertainty factor, e.g., of 10,000, would give the same regulatory "safe dose." Linear extrapolation to a virtually safe dose associated with a cancer risk estimate of less than one in a million would be 10 times lower than the reference dose based on the LTD10/10,000.

Benchmarking↗
PubMed1999

A unified approach to risk assessment for cancer and noncancer endpoints based on benchmark doses and uncertainty/safety factors.

A fundamental goal of toxicology is to determine safe levels of human exposure to toxic substances. In the absence of information to establish dose-response relationships at low exposure levels generally experienced by humans, high-dose to low-dose linear extrapolation is generally used for estimating carcinogenic risks and the no-observed-adverse-effect-level divided by uncertainty (safety) factors is widely used for establishing human exposure guidelines for noncancer effects. The basis and impact of this dichotomy is examined and questioned. It is proposed that a unified approach be adopted for establishing human exposure guidelines for both cancer and noncancer endpoints. It is suggested that a lower confidence limit on the dose estimated to produce an excess incidence of adverse health effects in 10% of the individuals in a human study or 10% of the animals in laboratory experiments be used as a point-of-departure. This dose would be divided by appropriate uncertainty factors to establish human exposure guidelines. For severe irreversible adverse health effects we suggest a total default uncertainty factor (divisor) for animal data on the order of 10,000, which is comparable to current guidelines. For reversible biological effects a smaller default uncertainty factor on the order of 1000 may be employed. This is comparable to the divisor often used currently when the point-of-departure is the lowest-observed-adverse-effect-level. It is asserted that the toxicological information generally available does not warrant numerical estimates of risk at low levels of human exposure. Rather, we support a unified approach for all adverse health effects of dividing a benchmark dose by appropriate uncertainty factors to establish guidelines for human exposures to toxic substances.

Benchmarking↗
PubMed2002

Impact of physiologically based pharmacokinetic modeling on benchmark dose calculations for TCDD-induced biochemical responses.

In risk assessment, noncancer risk is currently estimated using a no observed adverse effect level (NOAEL) from an experimental dose-response study, divided by uncertainty factors, to estimate a presumably safe level of human exposure. A benchmark dose approach, in which an effective dose (ED) resulting in a specified percentage increase over background for effects is estimated by empirical modeling, has been proposed as a replacement for the NOAEL methodology. The aim of this analysis is to compare methods for estimation of body burden resulting in a 1 or 10% maximum increase over background (BB(01) or BB(10)) for biochemical responses following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in female Sprague-Dawley rats. In one method, an ED resulting in a prespecified increase in response over background was estimated using average daily doses and an empirical Hill model. The ED was then converted to an equivalent body burden by a simple kinetic model assuming steady-state conditions, half-life of TCDD in the rat, and 100% absorption of TCDD. Alternatively, a mechanistic physiologically based pharmacokinetic (PBPK) model of TCDD in the rat was used to predict body burdens for administered doses. These PBPK-modeled body burdens were then used directly by the Hill model to calculate a BB(01) or BB(10). In general, the body burden values derived from EDs were within five-fold of BB(01) or BB(10) calculated from the PBPK model. BB(01) and BB(10) values from both methods were within two orders of magnitude of current human general population exposure to all dioxin-like compounds.

Animals↗
PubMed2006

Benchmarking performance in organ donation programs: dependence on demographics and mortality rates.

PURPOSE: Donors whose diagnosis of death is based upon neurologic criteria are the primary source of organs for human transplantation. The current measure of effectiveness of organ donation programs is the crude statistic, donors per million population (DPMP). This statistic represents the number of available donors, divided by the potential donor population. Comparisons between transplantation programs are done using the DPMP statistic. We sought to determine if variance in organ donation rates, reported as DPMP could be accounted for by differences in population demographics, specifically age and gender-specific mortality rates. METHODS: We obtained the population distribution and deaths for the year 2000 for the Calgary Health Region (CHR) and the country of Spain. Expected deaths were then calculated by standardizing the sample, based upon weighted averages of age, gender and cause-specific mortality rates. RESULTS: In 2000, Spain reported a crude organ donation rate of 33.9 DPMP. Standardizing the observed deaths in Spain using the CHR population distribution and calculating expected deaths based on the CHR rates, resulted in an adjusted rate of 19.2 DPMP (P < 0.05). CONCLUSIONS: These results bring into question the reliability of using crude DPMP as a measure of organ and tissue donation program performance. Alternative measures of benchmarking performance in organ donation programs should be considered.

Adolescent↗
PubMed2005

A method for benchmarking CT scanners.

This study involved the development of an objective method to compare the performance of five CT scanners for the purpose of benchmarking. The method used to assess the scanners was to determine the dose-normalised noise at a spatial resolution of 5.5 cm(-1). This gave a dose-normalised percent noise between 0.37% and 0.76%. The scanners were also assessed for radiation dose to patients undergoing abdomen and head CT examinations. Patients' dose-length product (DLP) for the abdomen clinical examinations varied from 305 to 685 mGy-cm, and for the head clinical examinations from 333 to 900 mGy-cm. The study results demonstrated that the comparison of dose and spatial resolution normalised percent noise levels is a useful method of comparing CT scanner performance.

Australia↗
PubMed2002

Laparoscopic cholecystectomy: quality of care and benchmarking. Results of a single-institution specialized in laparoscopy compared with those of a nationwide study in Switzerland.

BACKGROUND: Quality control is an important issue in surgery. Therefore, we assessed the outcome of laparoscopic cholecystectomies (LC) performed at our institution specialized in laparoscopic surgery in order to do a benchmarking. METHODS: The perioperative courses of the first 1000 LCs performed in Aarberg hospital were recorded, analyzed, and compared with the results of a recent study including 10, 174 patients published by the Swiss Association of Laparoscopic and Thoracoscopic Surgery (SALTS). RESULTS: The following quality indicators were compared with the corresponding SALTS rates: primary conversion rate 1.5% (SALTS 8.2%; p <0.01); conversion rate for intraoperative complications 6.5% (63.8%; p <0.01); intraoperative complication rate 22.2% (34.4%; p <0.01); postoperative morbidity rate 8.1% (10.4%; n.s.); in-hospital mortality rate 0.1% (0.2%; n.s.); and reoperation rate 0.8% (1.7%; n.s.). CONCLUSIONS: LC has reached a high quality level in its widespread use, but in a small specialized center even a higher quality level can be achieved. Favorable results seem to depend on structural advantages of a surveyable unit in association with a continuously motivated surgical team.

Adolescent↗
PubMed2006

Evaluation of target scores and benchmarks for the traversal task scenario of the Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) laparoscopy simulator.

BACKGROUND: The Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) simulator is validated for laparoscopy training, but benchmarks and target scores for assessing single tasks are needed. METHODS: Control data for the MIST-VR traversal task scenario were collected from 61 novices who performed the task 10 times over 3 days (1 h daily). Data were collected on the time taken, error score, economy of movement, and total score. Test differences were analyzed through percentage scores and t-tests for paired samples. RESULTS: Improvement was greatest over tests 1 to 5 (improvement: test(1.2), 38.07%; p = 0.000; test(4.5), 10.66%; p = 0.010): between tests 5 and 10, improvement slowed and scores stabilized. Variation in participants' performance fell steadily over the 10 tests. CONCLUSION: Trainees should perform at least 10 tests of the traversal task-five to get used to the equipment and task (automation phase; target total score, 95.16) and five to stabilize and consolidate performance (test 10 target total score, 74.11).

Adult↗