Kaplan-Meier analysis

Kawanishi DT, Brinker JA, Reeves R et al (1998) Kaplan-Meier analysis of freedom from extraction or death in patients with an Accufix J retention wire atrial permanent pacemaker lead a potential management tool. Pacing Clin Electrophysiol 21 2318-2321... 

The Kaplan-Meier estimator (Eq. 3) provides a maximum likelihood estimate of rehahility hut does not inform us about the dispersion aroimd R ti). This dispersion is captured by the variance or standard deviation of the estimator, which is then used to derive the upper and lower bounds for say a 95% confidence interval (that is, a 95% likelihood that the actual reliability will fall between the two calculated bounds, with the Kaplan-Meier analysis providing us with the most likely estimate). The variance of the estimator is provided by Greenwood s formula ... 

Fig. 27.5. Probability of verification of pneumonia by either detection of an infiltrate on a CXR or evidence of a relevant micro-organism during follow-up after HRCT. Kaplan-Meier analysis for patients with normal HRCT scans (grey line) and patients with pnemiionia on HRCT scans (black line). The dif-...

The assessment of patency of an implanted vascular graft or operation technique is a special modality of a clinical study. Valid comparisons on vascular access patency rates can be made only if patency is defined in a way that can be universally used by all specialties in a consistent manner [10]. Kaplan-Meier analysis is the most commonly used life table method in medical practice. It adequately copes with the issues such as patients for whom the event has not yet occurred and for those lost to follow-up. The data required by the method include the time of commencement of the treatment and the time the measured event occurred (e.g. thrombosis, infection). Patients who dropped out of treat-... 

Comparison of Kaplan-Meier survival estimates is often called for in clinical trial analysis. With survival analysis, you are trying to determine which treatment group displays a better time-to-event distribution than another. Part of this analysis is the production of Kaplan-Meier estimates plots that show the probability of a given event over time for each treatment group. In the following example you see that New Drug displays better survival estimates over time than either Old Drug or Placebo. ... 

Kaplan-Meier overall survival at 5 years was 52% (95% Cl 43-61%) for patients of HLA-matched group and 51% (95% Cl 33-69%) in HLA-mismatched group.The following variables were associated with improved patient survival in univariate analysis patient age <20 years (p=0.006), nonmalignant disease vs all others (p=0.01), AML (p=0.04), standard risk disease (p=0.0002), CMV seronegative patients (p=0.002). In multivariate analysis relative risks were determined as per Table 5. 

Liver dysfunction. In a 4-year study in 1221 liver dysfunction-free (serum aspartate aminotransferase [AST] and alanine aminotransferase [ALT] <39 lU/L and no medical care for or no past history of liver disease) males aged 35-56 years, was investigated for the association of coffee consumption with the development of increased serum AST and/or ALT activities. From the analysis using the Kaplan-Meier method, the estimated incidence of serum AST and/ or ALT > 40 lU/L, > 50 lU/L, and > 60 lU/ L decreased with an increase in coffee consumption. From the Cox proportional haz-... 

There is every reason to expect that this property would exist with olanzapine. Three fixed-dose ranges of olanzapine (5.0 2.5 mg, 10.0 2.5 mg, 15.0 2.5 mg) and one fixed-dose range of haloperidol (15.0 5 mg) were compared with placebo for up to 52 weeks of therapy (218). Survival analysis of time to rehospitalization for psychotic symptoms indicated that olanzapine was comparable to haloperidol and significantly better than placebo (p = 0.007). Kaplan-Meier estimation showed that 71.5% of olanzapine-treated patients did not relapse, compared with 32.8% for those on placebo. Further, another survival analysis demonstrated that significantly fewer patients in the olanzapine treatment group experienced relapse at any given time than those in the haloperidol group (i.e., p = 0.048 80.9% for olanzapine compared with 72.2% for haloperidol). 

Overall survival (Kaplan-Meier survival curve and non-parametric statistical analysis). 

Figures. Kaplan-Meier estimates of time to first notable serum creatinine increase in patients with multiple myeloma or breast cancer with bone metastases receiving 4 mg zoledronic acid or 90 mg pamidronate and Andersen-Gill multiple event analysis of the risk of elevated serum creatinine between treatment groups. After start of study drug. (Reprinted with permission from [75])...

Both studies used Kaplan-Meier survival curve analysis (2 19,225) to estimate the ultimate success rate in the NCE cohort under study. 25 Grabowski and Vernon s estimate of R D cash costs is less useful for corroborative purposes than Wiggins estimate because the... 

For several years, it has been acknowledged that whenever possible bioassay data should be corrected for early death. In both CDC s and EPA s analysis of Kociba et al (6), the individual animal pathology results were not available. Recently, these data were made available and the analysis showed some interesting results (76-77). The nonparametric Kaplan-Meier estimates of the probability of a female rat developing a hepatocellular neoplastic nodule or carcinoma by the end of 25 months, the duration of the Kociba study, are shown in Figure 5. These estimates are computed separately for each dose level and take into account the observation times of each rat. The values of these estimates for the two highest dose levels are 0.81 at... 

Kaplan-Meier estimator. A term from survival analysis. A statistic which was... 

Details of statistical analyses for potential toxicities that should be explicitly considered for all products and AEs of special interest Aiialyses for these events will in general be more comprehensive than for standard safety parameters. These analyses may include subject-year adjusted rates, Cox proportional hazards analysis of time to first event, and Kaplan-Meier curves. Detailed descriptions of the models would typically be provided. For example, if Cox proportional hazards analysis is specified, a detailed description of the model(s) that will be used should be provided. This would generally include study as a stratification factor, covariates, and model selection techniques. More advanced methods, such as multiple events models or competing risk analyses, should be described if used (as appropriate). It is recommended that graphical methods also be employed, for example, forest plot and risk-over-time plot (Xia et al., 2011). 

Nonparametric analysis provides powerful results since the rehahility calculation is unconstrained to fit any particular pre-defined lifetime distribution. However, this flexibility makes nonparametric results neither easy nor convenient to use for different purposes as often encountered in engineering design (e.g., optimization). In addition, some trends and patterns are more clearly identified and recognizable with parametric analysis. Several possible methods can be used to fit a parametric distribution to the nonparametric estimated rehability functions (as provided by the Kaplan-Meier estimator), such as graphical procedures or inference procedures. See Lawless (2003) for details. We choose in this paper the maximum likelihood estimation (MLE) technique, assuming that the sateUite subsystems failure data are arising from a WeibuU piobabihly distribution, as expressed in Equations 1,2. 

These data sunmiarize the results of Kaplan-Meier survival analysis as described (31). Statistical difference from untreated group (p< 0.001), (p < 0.0007). All mice were from a reduced litter size (36,55). All received ip injections at the indicated dose, except for LA which was administered subcutaneously. Compared to the untreated group, (-) indicates reduction of lifespan and NS indicates no significant difference. This table represents an update that includes previously published data. ALCAR, acetyl-L-carnitine, LA, lipoic acid (5S). 

Kaplan EL and Meier P (1958) Non-parametric estimation from incomplete observations Journal of the American Statistical Association, 53, 457-M81 Kaul S and Diamond GA (2006) Good enough a primer on the analysis and interpretation of non-inferiority trials Annals of Internal Medicine, 145, 62-69 Kay R (1995) Some fundamental statistical concepts in clinical trials and their application in herpes zoster Antiviral Chemistry and Chemotherapy, 6, Supplement 1, 28-33 Kay R (2004) An explanation of the hazard ratio Pharmaceutical Statistics, 3, 295-297... 

The analysis method attributed to Kaplan and Meier (1958) enables us to analyze the time to the first reported AE while accounting for different lengths of time at risk. To illustrate this method fully, we have modified the data from the previous example slightly, as shown in Figure 8.2. We refer to this new example as study 2. 

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