196,238 research outputs found
Appendix -Supplemental material for Adjustment for time-dependent unmeasured confounders in marginal structural Cox models using validation sample data
No full textSupplemental material, Appendix for Adjustment for time-dependent unmeasured confounders in marginal structural Cox models using validation sample data by Rebecca M Burne and Michal Abrahamowicz in Statistical Methods in Medical Research</p
Virginia Woolf as a short-story writer
No full textM. Abrahamowicz has chosen as subject for examination five of Virginia Woolf's short stories out of the collection A Haunted House and Other Short Stories \ Perhaps it is not very fair on the writer to select, for a separate subject, just this part of her work which is avowedly not her best. The small volume of her short stories was published posthumously by her husband, Leonard Woolf, in 1943: in his Foreword to it, he calls the reader's attention to the unfinished state in which most of them were left at the writer's death (...
Life course socioeconomic position and incidence of type 2 diabetes: Framingham offspring study
No full textB T Smith, E B Loucks, S Harper, M Abrahamowicz, C S Fox, J W Lync
Self-rated health in Canadian immigrants:analysis of the Longitudinal Survey of Immigrants to Canada
No full textAbstract not availableManinder Singh Setia, John Lynch, Michal Abrahamowicz, Pierre Tousignant, Amelie Quesnel-Valle
A systematic review of observational studies of the association between pioglitazone use and bladder cancer
No full text
Abrahamowicz M: Using generalized additive models to reduce residual confounding. Stat Med 2004
No full textSUMMARY Traditionally, confounding by continuous variables is controlled by including a linear or categorical term in a regression model. Residual confounding occurs when the e ect of the confounder on the outcome is mis-modelled. A continuous representation of a covariate was previously shown to result in a less biased estimate of the adjusted exposure e ect than categorization provided the functional form of the covariate-outcome relationship is correctly speciÿed. However, this is rarely known. In contrast to parametric regression, generalized additive models (GAM) ÿt a smooth dose-response curve to the data, without requiring a priori knowledge of the functional form. We used simulations to compare parametric multiple logistic regression vs its non-parametric GAM extension in their ability to control for a continuous confounder. We also investigated several issues related to the implementation of GAM in this context, including: (i) selecting the degrees of freedom; and (ii) alternative criteria for inclusion=exclusion of the potential confounder and for choosing between parametric and non-parametric representation of its e ect. The impact of the shape and strength of the confounder-disease association, sample size, and the correlation between the confounder and exposure were investigated. Simulations showed that when the confounder has a non-linear association with the outcome, compared to a parametric representation, GAM modelling (i) reduced the mean squared error for the adjusted exposure e ect; (ii) avoided in ation of the type I error for testing the exposure e ect. When the true confounder-outcome relationship was linear, GAM performed as well as the parametric logistic regression. When modelling a continuous exposure non-parametrically, in the presence of a continuous confounder, our results suggest that assuming a linear e ect of the confounder and focussing on the non-linearity of the exposure-outcome relationship leads to spurious ÿndings of non-linearity: joint non-linear modelling is necessary. Overall, our results suggest that the use of GAM to reduce residual confounding o ers several improvements over conventional parametric modelling
Sex Differences in Cardiovascular Effectiveness of Newer Glucose-Lowering Drugs Added to Metformin in Type 2 Diabetes Mellitus
No full textBackground: Randomized controlled trials showed that newer glucose-lowering agents are cardioprotective, but most participants were men. It is unknown whether benefits are similar in women. Methods and Results: Among adults with type 2 diabetes mellitus not controlled with metformin with no prior use of insulin, we assessed for sex differences in the cardiovascular effectiveness and safety of sodium-glucose-like transport-2 inhibitors (SGLT-2i), glucagon-like peptide-1 receptor agonists (GLP-1RA), dipeptidyl peptidase-4 inhibitors, initiated as second-line agents relative to sulfonylureas (reference-group). We studied type 2 diabetes mellitus American adults with newly dispensed sulfonylureas, SGLT-2i, GLP-1RA, or dipeptidyl peptidase-4 inhibitors (Marketscan-Database: 2011–2017). We used multivariable Cox proportional hazards models with time-varying exposure to compare time to first nonfatal cardiovascular event (myocardial infarction/unstable angina, stroke, and heart failure), and safety outcomes between drugs users, and tested for sex–drug interactions. Among 167 254 type 2 diabetes mellitus metformin users (46% women, median age 59 years, at low cardiovascular risk), during a median 4.5-year follow-up, cardiovascular events incidence was lower in women than men (14.7 versus 16.7 per 1000-person-year). Compared with sulfonylureas, hazard ratios (HRs) for cardiovascular events were lower with GLP-1RA (adjusted HR-women: 0.57, 95% CI: 0.48–0.68; aHR-men: 0.82, 0.71–0.95), dipeptidyl peptidase-4 inhibitors (aHR-women: 0.83, 0.77–0.89; aHR-men: 0.85, 0.79–0.91) and SGLT-2i (aHR-women: 0.58, 0.46–0.74; aHR-men: 0.69, 0.57–0.83). A sex-by-drug interaction was statistically significant only for GLP-1RA (P=0.002), suggesting greater cardiovascular effectiveness in women. Compared with sulfonylureas, risks of adverse events were similarly lower in both sexes for GLP-1RA (aHR-women: 0.81, 0.73–0.89; aHR-men: 0.80, 0.71–0.89), dipeptidyl peptidase-4 inhibitors (aHR-women: 0.82, 0.78–0.87; aHR-men: 0.83, 0.78–0.87) and SGLT-2i (aHR-women: 0.68, 0.59–0.78; aHR-men: 0.67, 0.59–0.78) (all sex–drug interactions for adverse events P>0.05). Conclusions: Newer glucose-lowering drugs were associated with lower risk of cardiovascular events than sulfonylureas, with greater effectiveness of GLP-1RA in women than men. Overall, they appeared safe, with a better safety profile for SGLT-2i than for GLP-1RA regardless of sex
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
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