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Topic: Hazard ratio


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In the News (Sun 3 Jun 12)

  
  Hazard ratio - Wikipedia, the free encyclopedia
The hazard ratio in survival analysis is the effect of an explanatory variable on the hazard or risk of an event.
The instantaneous hazard rate is the limit of the number of events per unit time divided by the number at risk as the time interval decreases.
The hazard ratio is the effect on this hazard rate of a difference, such as group membership (for example, treatment or control, male or female), as estimated by regression models which treat the log of the hazard rate as a function of a baseline hazard h
en.wikipedia.org /wiki/Hazard_ratio   (290 words)

  
 Odds ratio - Wikipedia, the free encyclopedia
The odds ratio is a measure of effect size particularly important in Bayesian statistics and logistic regression.
It is defined as the ratio of the odds of an event occurring in one group to the odds of it occurring in another group, or to a sample-based estimate of that ratio.
The increased use of logistic regression in medical and social science research means that the odds ratio is commonly used as a means of expressing the results in some forms of clinical trials, such as case-controlled trials, and in survey research.
en.wikipedia.org /wiki/Odds_ratio   (465 words)

  
 IR Applications 5
The hazard ratio is the ratio of two hazard functions that allows investigators to measure the association between the risk factors and the effects of such factors on the risk functions.
The hazard ratio is the ratio of the relative hazard to the risk factor (X) changes, i.e., the relative hazard of X = 0 compared to the relative hazard of X = 1.
Because the hazard ratio of 0.35 was a positive fraction and less than one, it is more meaningful to interpret that male students had almost three times (inverse of 0.35) less of a hazard than female students to experience academic difficulty.
www.airweb.org /print.asp?page=316   (13485 words)

  
 The Effects of Diabetes on the Risks of Major Cardiovascular Diseases and Death in the Asia-Pacific Region -- Asia ...
The hazard ratio for all-causes mortality was 1.68 (1.55–1.84),
The hazard ratio for the composite outcome of death from
Figure 3— Sex-, study-, and age-adjusted hazard ratios (on a log scale) for noncardiovascular deaths and deaths from all causes (diabetic versus nondiabetic), overall and by geographic area.
care.diabetesjournals.org /cgi/content/full/26/2/360   (3763 words)

  
 Hazard ratio   (Site not responding. Last check: 2007-10-30)
The hazard ratio in survival analysis is a summary of the difference between two survival curves, representing the reduction in the risk of death on treatment compared to control, over the period of follow-up.
Proportional hazards regression models (also called Cox regression models after their inventor) assume that the relative risk of death between treatments and controls is constant at each interval of time.
The Price-to-Earnings ratio of a stock is a number calculated from the price per share of the stock divided by the earnings per share of that stock for the past 12 months.
www.serebella.com /encyclopedia/article-Hazard_ratio.html   (330 words)

  
 Table 2
Hazard ratios, confidence intervals and P values are given for the results of both the univariate analyses and the multivariate analyses.
For univariate and multivariate analyses, the hazard ratio is given for nuclear and cytoplasmic p21
The multivariate analysis is adjusted for the Nottingham Prognostic Index (NPI) (nodes, grade and size) and for treatment (tamoxifen/chemotherapy/no treatment), with the NPI based on imputed grades and tumour sizes where the relevant data were missing as described in the statistical methods.
www.breast-cancer-research.com /content/5/6/r242/table/T2   (137 words)

  
 Hazard Ratio in Clinical Trials -- Spruance et al. 48 (8): 2787 -- Antimicrobial Agents and Chemotherapy
The hazard ratio is constant under the Cox proportional hazard model.
The hazard ratio is an estimate of the ratio of the hazard rate
An assumption of proportional hazards regression is that
aac.asm.org /cgi/content/full/48/8/2787   (2942 words)

  
 Intuitive Biostatistics: Comparing Two Survival Curves
If the ratio is 0.5, then the relative risk of dying in one group is half the risk of dying in the other group.
Programs that calculate proportional hazards compute the best-fit values for each of the relative risks (hazard ratios), along with their 95% Cl. If you encounter a program (or publication) that reports P coefficients instead of odds ratios, it is easy to convert.
The proportional hazards regression model is simple, probably too simple to account for many kinds of data, as it assumes that each X variable contributes independently to the relative risk.
www.graphpad.com /www/book/compsurv.htm   (2192 words)

  
 Randomised trial of surgery alone versus surgery followed by radiotherapy for mobile cancer of the rectum. Medical ...
The hazard ratio for overall survival was 0.84 (95% CI 0.65-1.07, p = 0.17).
The corresponding numbers with distant recurrence were 83 and 75 (hazard ratio 0.85 [0.63-1.114], p = 0.18).
The hazard ratio for disease-free survival was 0.85 (0.65-1.08; p = 0.18).
www.meb.uni-bonn.de /cgi-bin/mycite?ExtRef=MEDL/97121324   (326 words)

  
 Final Environmental Impact Statement for the Tank Waste Remediation System, Hanford Site,
This acute hazard ratio was primarily attributable to mercury (approximately 89 percent of the overall hazard ratio).
This acute hazard ratio was primarily attributable to TOC (approximately 87 percent of the overall ERPG-2 ratio).
This acute hazard ratio was also primarily attributable to TOC (approximately 90 percent of the overall ERPG-3 ratio) However, the MEI noninvolved worker is a hypothetical worker assumed to be located 100 m (330 ft) from the source area.
www.globalsecurity.org /wmd/library/report/enviro/eis-0189/app_e_11.htm   (7968 words)

  
 B06-20 Year F/U: Mast/Lump w/wo RTx
The hazard ratio for death among the women who underwent lumpectomy alone, as compared with those who underwent total mastectomy, was 1.05 (95 percent confidence interval, 0.90 to 1.23; P=0.51).
The hazard ratio for death among the women who underwent lumpectomy followed by breast irradiation, as compared with those who underwent total mastectomy, was 0.97 (95 percent confidence interval, 0.83 to 1.14; P=0.74).
Among the lumpectomy-treated women whose surgical specimens had tumor-free margins, the hazard ratio for death among the women who underwent postoperative breast irradiation, as compared with those who did not, was 0.91 (95 percent confidence interval, 0.77 to 1.06; P=0.23).
www.annieappleseedproject.org /protb0yearfu.html   (362 words)

  
 Hazard Ratio
Hazard Ratio : A term used to compare an animal's daily dietary intake of a pesticide to its LD 50 value.
A ratio greater than 1.0 indicates that the animal is likely to consume an a dose amount which would kill 50 percent of animals of the same species.
A note on point estimation of the hazard ratio in exponential...
www.mongabay.com /reference/environment/Hazard_Ratio.html   (329 words)

  
 Survival and Clinical Trial Design: Tarceva.com
Hazard ratio of 0.73 indicates a 27% reduction in risk of death for patients who received Tarceva as compared to placebo.
Hazard ratio represents the reduction in the risk of death with treatment compared to placebo and measures the average improvement in survival over the course of a clinical trial.
In the pancreatic cancer Phase III trial, hazard ratio (based on a log-rank test) was used prospectively to define the primary endpoint of overall survival.
www.tarceva.com /tarceva/professional/survival/survival.jsp   (422 words)

  
 Result Content View   (Site not responding. Last check: 2007-10-30)
The hazard ratio (letrozole/placebo) for recurrence showed a statistically significant (p=0.02) trend to a decrease over time indicating a greater benefit of letrozole over time.
Conclusions: This analysis of the hazard ratios for disease recurrence over time between the letrozole and placebo arms of MA.17 indicates that, at least out to 4 years, the longer patients are exposed to letrozole, the greater the benefit.
The increasing HR in the placebo group is of note and emphasizes the residual risk of recurrence that exists in women completing 5 years of tamoxifen To further address the issue of duration of letrozole therapy, a re-randomization of all participants completing letrozole on MA.17 to a further 5 years of treatment is underway.
www.abstracts2view.com /sabcs05/view.php?nu=SABCS05L_378&terms=   (358 words)

  
 Pharmacologic Management of Heart Failure and Left Ventricular Systolic Dysfunction: Effect in Female, Black, and ...   (Site not responding. Last check: 2007-10-30)
The log ratio of relative risks equals the log of the relative risk for women divided by the relative risk for men, and its standard error equals the square root of the sum of the variances of the two log relative risks.
This difference between the estimates of relative risk and hazard ratios is due to the inclusion in the hazard ratio analysis of the AIRE study, which reported a slight nonsignificant mortality benefit for women compared to men treated with ramipril.
The corresponding estimates for the hazard ratio are 0.73 (95% CI: 0.56, 0.95) for diabetics and 0.80 (95% CI: 0.69, 0.93) for nondiabetics.
www.ahcpr.gov /clinic/epcsums/hrtfailsum.htm   (4533 words)

  
 The Prism Guide to Interpreting Statistical Results
The hazard is the slope of the survival curve – a measure of how rapidly subjects are dying.
If the hazard ratio is 2.0, then the rate of deaths in one treatment group is twice the rate in the other group.
The computation of the hazard ratio assumes that the ratio is consistent over time, and that any differences are due to random sampling.
www.graphpad.com /articles/interpret/survival/survival.htm   (940 words)

  
 Final Environmental Impact Statement for the Tank Waste Remediation System, Hanford Site, Richland, Washington
This acute hazard ratio was also primarily attributable to TOC (approximately 90 percent of the overall ERPG-3 ratio) However, the MEI noninvolved worker is a hypothetical worker assumed to be located 100m (330 ft) from the source area.
Under bounding conditions (Table E.4.3.11), the cumulative acute hazard ratios for the MEI noninvolved worker and nearest noninvolved worker (335 workers at 290 m [950 ft]) were 7.31E+02 and 2.65, respectively for ERPG-3, indicating the potential for irreversible health effects that could be life threatening.
Under bounding conditions (Table E.2.2.19), the cumulative acute hazard ratios for the MEI noninvolved worker and nearest noninvolved worker (335 workers at 290 m [950 ft]) were 7.31E+02 and 2.65E+00, respectively for ERPG-3, indicating the potential for irreversible health effects that could be life threatening.
www.eh.doe.gov /NEPA/eis/eis0189/app_e_4.htm   (7852 words)

  
 Hazard Ratio
The data in the table shows that the treatment increased and decreased certain health risks for the group of participants who were in the Estrogen + Progestin group.
For health risks that have a Hazard Ratio greater than one, it means that the chances of getting that health risk increased with the treatment.
For health risks that have a Hazard Ratio less than one, it means that the chances of getting that health risk decreased with the treatment.
student.biology.arizona.edu /honors2002/group03/Statistics.htm   (158 words)

  
 169   (Site not responding. Last check: 2007-10-30)
Results show that, while the hazard rate for the MALE variable is small (hazard ratio=1.19, p<0.10), the impact of certain indicators vary significantly by gender.
First grade retention was a risk factor for males (hazard ratio=1.65, p<0.05) but had no relationship to the risk of dropout for females (hazard ratio=1.20).
The number of parental quarters employed approached significance as a risk factor for females (hazard ratio=3.93, p<0.10) but was not related to dropout for males (hazard ratio=1.03).
www.sswr.org /papers2001/169.htm   (297 words)

  
 Hazard Ratio   (Site not responding. Last check: 2007-10-30)
It is also called proportional hazards model because it estimates the ratio of the risks (hazard ratio or relative hazard).
1) The hazard ratio must be defined relative to a baseline group.
Relative Risk or Risk Ratio (sometimes also called Hazard Ratio or Odds Ratio, but as the meaning of odds is quite different, especially in,...
www.hazardratio.info   (352 words)

  
 Getting Started
In this model, the hazards ratio (or risk ratio) for Group, defined as the exponentiation of the regression coefficient for Group, is the ratio of the hazard functions between the two groups.
If the hazard ratio changes with time, the proportional hazards model assumption is invalid.
represents the hazard ratio at the geometric mean of the survival times.
www.asu.edu /sas/sasdoc/sashtml/stat/chap49/sect2.htm   (690 words)

  
 [No title]
This ratio indicates the expected change in the risk of the terminal event when X changes from 0 to 1.
If the hazard ratio (1 The IV is associated with increased survival If the hazard ratio is (1 The IV is associated with decreased survival The Log-Relative Hazard The log-relative hazard is derived by taking the logarithm of both sides of the hazard ratio.
Hazard function Also called the hazard rate, a graph that illustrates how likely a parolee is to be revoked given that he/she has been successful up to time (t) This can also be broken out for cases with and without a prior probation violation.
www.shsu.edu /~icc_cmf/cj_789/coxRegression.doc   (1366 words)

  
 Lipids Online Slides: total cholesterol:HDL-C ratio, C-reactive protein
Among patients with below-median total cholesterol:HDL-C ratios, the NNT in those with an elevated CRP was also quite comparable, whereas in those with a low level of CRP, the absolute event rate was low and the efficacy of lovastatin was minimal, with the result that the NNT was very large.
The combined predictive value of lipid and CRP levels on mortality was evaluated in a prospective study of 985 patients with severe coronary artery disease, defined as at least 70% stenosis in at least 1 coronary artery or a primary branch; 109 patients (11%) died during the mean 3.0-year follow-up.
In patients overall, prescription of a statin was associated with improved mortality (hazard ratio 0.39; 95% confidence interval [CI] 0.20–0.78; p=0.002); of the 172 patients (19%) prescribed statin therapy, 63% were prescribed simvastatin, 15% atorvastatin, 13% pravastatin, 5% lovastatin, and 4% fluvastatin.
lipidsonline.org /slides/slide01.cfm?q=total+cholesterol:HDL-C+ratio   (590 words)

  
 Riluzole for amyotrophic lateral sclerosis (ALS)/motor neuron disease (MND) (Cochrane Review)
Primary: pooled hazard ratio of tracheostomy-free survival over all time points with riluzole 100 mg.
A test of drug efficacy was based on the Parmar pooled hazard ratio.
Riluzole 100 mg per day provided a benefit for the homogeneous group of patients in the first two trials (p = 0.039, hazard ratio 0.80, 95% confidence interval 0.64 to 0.99) and there was no evidence of heterogeneity (p = 0.33).
www.update-software.com /abstracts/AB001447.htm   (726 words)

  
 Cancer Resources—Cancer News, Cancer Conferences, Cancer Causes, Cancer Prevention
Compared to those in the first group, their hazard ratio was 1.1.
In the 1082 with atrophic levels of pepsinogen and who were positive for H. pylori antibody, the incidence was 0.35% and the hazard ratio was 6.0.
In the remaining 443 subjects who had atrophic pepsinogen and were negative for H. pylori antibody, the incidence was 0.60% and the hazard ratio 8.2.
cancer.med.upenn.edu /resources/article.cfm?c=3&s=8&ss=23&Year=2005&Month=05&id=11928   (392 words)

  
 PF Online Feature Article - Safe Exhaust Recirculation of Manned Spray Booths
Since paint formulations contain a mixture of solvents, a Hazard Ratio must be calculated for each solvent by dividing the actual concentration of the specific solvent by its respective PEL.
At a minimum, the protection factor required for the PPE to be used must exceed the highest Hazard Ratio.
In situations where the PPE protection factor is many times higher than the highest Hazard Ratio, painter exposure to solvent in the recirculated booth may be lower than it would be without PPE and recirculation.
www.pfonline.com /articles/020303.html   (950 words)

  
 Respirators WAC 296-842 HT2
Step 3: If the respiratory hazard is a single substance, select the highest hazard ratio value and skip to Step 6.
If the respiratory hazard is a mixture of substances, you’ll need to determine if substances in the mixture have additive health effects.
Step 6: Compare your hazard ratio value to the APF values in Table 5 of Chapter 296-842 WAC, Respirators.
www.lni.wa.gov /WISHA/Rules/respirators/HTML/HT2.htm   (1076 words)

  
 Sensitivity of the Hazard Ratio to Non-Ignorable Treatment Assignment in an Observational Study
We extend their method to assess sensitivity of the treatment hazard ratio to hidden bias under a range of covariate distributions.
We derive simple formulas for approximating the true from the apparent treatment hazard ratio estimated under a specific survival model, and assess the validity of these formulas in simulation studies.
Nandita Mitra and Daniel F. Heitjan, "Sensitivity of the Hazard Ratio to Non-Ignorable Treatment Assignment in an Observational Study" (March 2006).
www.biostatsresearch.com /upennbiostat/papers/art5   (251 words)

  
 Applied Survival Analysis by Hosmer and Lemeshow, Chapter 4
The coefficients and hazard ratio from the proportional hazard model which includes the design variables for age.
Proportional hazard model including the design variables for age using deviation from mean coding.
Three proportional hazard models: the first containing only the predictor treat, the second containing both treat and age, and the third containing treat, age and the interaction of treat and age.
www.ats.ucla.edu /stat/sas/examples/asa/asa4.htm   (1308 words)

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