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To allow for non-linear exposure-response relationships, we applied flexible non-parametric smoothing techniques to models of time to lung cancer mortality in two occupational cohorts with skewed exposure distributions. We focused on three different smoothing techniques in Cox models: penalized splines, restricted cubic splines, and fractional polynomials. We compared standard software implementations of these three methods based on their visual representation and criterion for model selection. We propose a measure of the difference between a pair of curves based on the area between them, standardized by the average of the areas under the pair of curves. To capture the variation in the difference over the range of exposure, the area between curves was also calculated at percentiles of exposure and expressed as a percentage of the total difference. The dose-response curves from the three methods were similar in both studies over the denser portion of the exposure range, with the difference between curves up to the 50th percentile less than 1 per cent of the total difference. A comparison of inverse variance weighted areas applied to the data set with a more skewed exposure distribution allowed us to estimate area differences with more precision by reducing the proportion attributed to the upper 1 per cent tail region. Overall, the penalized spline and the restricted cubic spline were closer to each other than either was to the fractional polynomial.

OBJECTIVE The purpose of this trial was to compare usual patient education plus the Internet-based, Personal Patient Profile-Prostate, versus usual education alone, on conflict associated with decision making, plus explore time-to-treatment and treatment choice. METHODS A randomized, multi-center clinical trial was conducted with measures at baseline, one and six months. Men with newly diagnosed localized prostate cancer who sought consultation at urology, radiation oncology or multi-disciplinary clinics in four geographically-distinct American cities were recruited. Intervention group participants used the Personal Patient Profile-Prostate, a decision support system comprised of customized text and video coaching regarding potential outcomes, influential factors, and communication with care providers. The primary outcome, patient-reported decisional conflict, was evaluated over time using Generalized Estimating Equations to fit generalized linear models. Additional outcomes, time-to-treatment, treatment choice and program acceptability/usefulness, were explored. RESULTS A total of 494 eligible men were randomized (266 intervention; 228 control). The intervention reduced adjusted decisional conflict over time as compared with the control group, for the uncertainty score (estimate −3.61; (confidence interval, −7.01,−0.22) and values clarity (estimate −3.57; confidence interval (−5.85,−1.30) Borderline effect was seen for the total decisional conflict score (estimate −1.75; confidence interval (−3.61,0.11). Time-to-treatment was comparable between groups, while undecided men in the intervention group chose brachytherapy more often than in the control group. Acceptability and usefulness were highly rated. CONCLUSION The Personal Patient Profile-Prostate is the first intervention to significantly reduce decisional conflict in a multi-center trial of American men with newly diagnosed localized prostate cancer. Our findings support efficacy of P3P for addressing decision uncertainty and facilitating patient selection of a prostate cancer treatment that is consistent with the patient values and preferences.

We examined the behavior of alternative smoothing methods for modeling environmental epidemiology data. Model fit can only be examined when the true exposure-response curve is known and so we used simulation studies to examine the performance of penalized splines (Psplines), restricted cubic splines (RCS), natural splines (NS), and fractional polynomials (FP). Survival data were generated under six plausible exposure-response scenarios with a right skewed exposure distribution, typical of environmental exposures. Cox models with each spline or FP were fit to simulated datasets. The best models, e.g. degrees of freedom, were selected using default criteria for each method. The root mean-square error (rMSE) and area difference were computed to assess model fit and bias (difference between the observed and true curves). The test for linearity was a measure of sensitivity and the test of the null was an assessment of statistical power. No one method performed best according to all four measures of performance, however, all methods performed reasonably well. The model fit was best for P-splines for almost all true positive scenarios, although fractional polynomials and RCS were least biased, on average.

In survival analysis, frailty models are potential choices for modeling unexplained heterogeneity in a population. This tutorial presents an overview and general framework of frailty modeling and estimation for multiplicative hazards models in the context of biomedical and genetic studies. Other topics in frailty models, such as diagnostic methods for model adequacy and inference in frailty models, are also discussed. Examples of analyses using multivariate frailty models in a non-parametric hazards setting on biomedical datasets are provided, and the implications of choosing to use frailty and relevance to genetic applications are discussed.

PURPOSE. The purpose of this study was to assess risk factors associated with soft contact lens (SCL)-related corneal infiltrative events (CIEs).METHODS. This was a single-visit, case-control study conducted at five academic centers in North America. Cases were defined as current SCL wearers with a symptomatic CIE. For each case, three age-and sex-matched controls were enrolled. Subjects completed the Contact Lens Risk Survey (CLRS), a standardized scripted medical interview, supplied a recent health history, and underwent an ocular examination. Microbial culturing of the ocular surface, SCL, and lens storage case was conducted for all cases and one of the three matched controls. Univariate and multivariate logistic regression modeling were used to assess the risk of developing a CIE.RESULTS. Thirty cases and 90 controls 13 to 31 years of age completed the study. Corneal infiltrative event diagnosis included contact lens-associated red eye, infiltrative keratitis, and contact lens peripheral ulcer. Subjects with symptomatic CIEs were more likely to harbor substantial levels of gram-negative bioburden on the ocular surface and contact lens. Significant risk factors for developing a CIE were overnight wear of SCLs, use of multipurpose solution, rinsing SCLs with water, lens storage case older than 6 months, previous ''red eye'' event, use of ocular drops in the past week, and illness during the past week.CONCLUSIONS. This pilot study demonstrated feasibility of enrolling a representative pool of SCL wearers with an untreated, symptomatic CIE and assessing CIE risk factors by using standardized methods. A larger sample size is needed to determine relationships between patient-reported behaviors and exposures, microbial bioburden, and CIE development.Keywords: adverse events, contact lenses, corneal infiltrative events, microbial culturing A recent report from the US Centers for Disease Control and Prevention (CDC) called to light the substantial burden associated with contact lens-related complications.1 The CDC report estimated that contact lens-related keratitis results in nearly 1 million doctor visits each year and carries an associated cost of $175 million.1 This estimate does not include the additional ''costs'' to the patient such as pain or discomfort, missed school or work, and potential for permanent loss of vision.Approximately 37 million people in the United States currently wear contact lenses and, due to the increasing prevalence of myopia, more and younger patients are expected to begin wearing contact lenses to aid in its management. 2,3 Research has demonstrated that adult and pediatric patients can safely wear soft contact lenses (SCLs) within controlled trials, with relatively low rates of complications, especially for daily lens wear. 4,5 However, as with most medical devices, when contact lenses are used by the general population outside of controlled trials, the rate and types of complications increase. 1,[6][7][8] The increased risk of complications is likely caused by poor wear and care beha...

Objectives To assess the frequency and predictors of vascular closure device (VCD) deployment failure, and its association with vascular complications of three commonly used VCDs. Background VCDs are commonly used following percutaneous coronary intervention (PCI) on the basis of studies demonstrating reduced time to ambulation, increased patient comfort, and possible reduction in vascular complications as compared to manual compression. However, limited data are available on the frequency and predictors of VCD failure, and the association of deployment failure with vascular complications. Methods From a de-identified dataset provided by Massachusetts Department of Health, 23,813 consecutive interventional coronary procedures that used either a collagen plug-based (n=18,533) or nitinol clip-based (n=2,284) or suture-based (n=2,996) VCD between 06/2005 and 12/2007 were identified. We defined VCD failure as unsuccessful deployment or failure to achieve immediate access site hemostasis. Results Among 23,813 procedures, VCD failed in 781 (3.3%) procedures (2.1% of collagen plug-based, 6.1% of suture-based, 9.5% of nitinol clip-based). Patients with VCD failure had excess risk of ‘any’ (7.7% versus 2.8%; P<0.001), major (3.3% versus 0.8%; P<0.001), or minor (5.8% versus 2.1%; P<0.001) vascular complications compared with successful VCD deployment. In a propensity-score adjusted analysis, when compared with collagen plug-based VCD (Reference OR =1.0), nitinol clip-based VCD had 2-fold increased risk (OR 2.0, 95% CI: 1.8–2.3, p<0.001) and suture-based VCD had 1.25-fold increased risk (OR 1.25, 95% CI: 1.2–1.3, p<0.001) for VCD failure. VCD failure was a significant predictor of subsequent vascular complications for both collagen plug-based VCD and nitinol clip-based VCD, but not for suture-based VCD. Conclusion VCD failure rates vary depending upon the types of VCD used and are associated with significantly higher vascular complications as compared to deployment successes.

These results describe the EH-VMRT ability of professional baseball players and show a significant relationship between the EH-VMRT ability and batting performance. These results may suggest a possible role in player selection, indicating that batters with better EH-VMRT may be more likely to reach the major-league level and be more productive for their team. Further studies will be needed to demonstrate whether training better EH-VMRT results in improved batting performance.