173 research outputs found
Methods for medical device and surgical epidemiology: applications in knee replacement and COVID-19 related tracheotomy
No full textAlthough medical devices (MDs) and surgery have been part of medicine since its start, the methods for their study in epidemiology have not kept pace with the developments in pharmacoepidemiology. The recent increased attention from society to the potential harms of unsafe implants has led to improved legislation that call for a much closer evaluation of MDs. However, the evaluation of MDs and surgery presents unique caveats and challenges, such as the ascertainment of the indication of the surgery or how to include surgeon characteristics in the analysis, that can greatly influence outcomes.
To advance research on how one can overcome these challenges, I tested several methods. I used Propensity Score (PS) methods, namely PS matching, stratifications and inverse probability weighting (IPW); and Instrumental Variables (IVs), based on surgeon and hospital preference in the study of the effectiveness and safety of partial vs total knee replacement and evaluated them by comparing observational results to those from a randomised controlled trial. I applied the target trial framework to the study of the timing of tracheostomy in patients with COVID-19. I further studied the safety of knee replacements using the self-controlled case series method. I studied the potential heterogeneity by subgroups (on high-risk patients, by gender, by age, and by deprivation) on the safety and effectiveness of knee replacements. I explored the effect of surgical volume on knee replacement outcomes. I finally used simulation studies to examine the flaws and challenges of preference-based IV.
I found that PS stratification and IPW may be able to minimise confounding and bias in the study of partial vs total knee replacement, provided that the study is carefully designed to consider both patient and surgeon characteristics. I also showed how preference-based IVs may not be fit for purpose for this use case.
Future research is needed to examine whether my findings are generalisable to other settings and whether other IVs can be used safely in MD and surgical research
Hospitalizations in Patients With Heart Failure: Who and Why⁎⁎Editorials published in the Journal of the American College of Cardiologyreflect the views of the authors and do not necessarily represent the views of JACCor the American College of Cardiology.
No full textAssociations of Kidney Function with Cardiovascular Medication Use after Myocardial Infarction
No full textExtended supplementary methods.
No full textIntroductionMuch of the data on BMI-mortality associations stem from 20th century U.S. cohorts. The purpose of this study was to determine the association between BMI and mortality in a contemporary, nationally representative, 21st century, U.S. adult population.MethodsThis was a retrospective cohort study of U.S. adults from the 1999–2018 National Health Interview Study (NHIS), linked to the National Death Index (NDI) through December 31st, 2019. BMI was calculated using self-reported height & weight and categorized into 9 groups. We estimated risk of all-cause mortality using multivariable Cox proportional hazards regression, adjusting for covariates, accounting for the survey design, and performing subgroup analyses to reduce analytic bias.ResultsThe study sample included 554,332 adults (mean age 46 years [SD 15], 50% female, 69% non-Hispanic White). Over a median follow-up of 9 years (IQR 5–14) and maximum follow-up of 20 years, there were 75,807 deaths. The risk of all-cause mortality was similar across a wide range of BMI categories: compared to BMI of 22.5–24.9 kg/m2, the adjusted HR was 0.95 [95% CI 0.92, 0.98] for BMI of 25.0–27.4 and 0.93 [0.90, 0.96] for BMI of 27.5–29.9. These results persisted after restriction to healthy never-smokers and exclusion of subjects who died within the first two years of follow-up. A 21–108% increased mortality risk was seen for BMI ≥30. Older adults showed no significant increase in mortality between BMI of 22.5 and 34.9, while in younger adults this lack of increase was limited to the BMI range of 22.5 to 27.4.ConclusionThe risk of all-cause mortality was elevated by 21–108% among participants with BMI ≥30. BMI may not necessarily increase mortality independently of other risk factors in adults, especially older adults, with overweight BMI. Further studies incorporating weight history, body composition, and morbidity outcomes are needed to fully characterize BMI-mortality associations.</div
Baseline characteristics by BMI category among NHIS 1999–2018 participants.
No full textBaseline characteristics by BMI category among NHIS 1999–2018 participants.</p
S1-S4 Figs and S1-S10 Tables.
No full textIntroductionMuch of the data on BMI-mortality associations stem from 20th century U.S. cohorts. The purpose of this study was to determine the association between BMI and mortality in a contemporary, nationally representative, 21st century, U.S. adult population.MethodsThis was a retrospective cohort study of U.S. adults from the 1999–2018 National Health Interview Study (NHIS), linked to the National Death Index (NDI) through December 31st, 2019. BMI was calculated using self-reported height & weight and categorized into 9 groups. We estimated risk of all-cause mortality using multivariable Cox proportional hazards regression, adjusting for covariates, accounting for the survey design, and performing subgroup analyses to reduce analytic bias.ResultsThe study sample included 554,332 adults (mean age 46 years [SD 15], 50% female, 69% non-Hispanic White). Over a median follow-up of 9 years (IQR 5–14) and maximum follow-up of 20 years, there were 75,807 deaths. The risk of all-cause mortality was similar across a wide range of BMI categories: compared to BMI of 22.5–24.9 kg/m2, the adjusted HR was 0.95 [95% CI 0.92, 0.98] for BMI of 25.0–27.4 and 0.93 [0.90, 0.96] for BMI of 27.5–29.9. These results persisted after restriction to healthy never-smokers and exclusion of subjects who died within the first two years of follow-up. A 21–108% increased mortality risk was seen for BMI ≥30. Older adults showed no significant increase in mortality between BMI of 22.5 and 34.9, while in younger adults this lack of increase was limited to the BMI range of 22.5 to 27.4.ConclusionThe risk of all-cause mortality was elevated by 21–108% among participants with BMI ≥30. BMI may not necessarily increase mortality independently of other risk factors in adults, especially older adults, with overweight BMI. Further studies incorporating weight history, body composition, and morbidity outcomes are needed to fully characterize BMI-mortality associations.</div
Association between BMI and All-cause mortality by gender and age group.
No full textFig 3 shows the hazard ratios for BMI categories, relative to a BMI of 22.5–24.9, by gender and age group. All figures exclude first two years of follow-up. Confidence bands represent 95% CI. The blue line represents all individuals in subgroup. The red line depicts healthy, never-smoking individuals within subgroup. Healthy defined as no self-reported history of cardiovascular disease or non-skin cancer or melanoma. (A) presents the hazard ratios among females<65 years overall. (B) presents the hazard ratios for females greater than or equal to 65. (C) presents the hazard ratios among males<65. (D) presents the hazard ratios among males greater than or equal to 65. Please note that hazard ratios for BMI groups for all subjects and healthy, never-smokers are relative to different reference groups and thus may not be comparable.</p
Association between BMI and all-cause mortality by gender and age group.
No full textFig 4 shows the hazard ratios for BMI categories, relative to a BMI of 22.5–24.9, by race/ethnicity. Confidence bands represent 95% CI. The blue line represents all individuals. The red line depicts healthy, never-smoking individuals. Healthy defined as no self-reported history of cardiovascular disease or non-skin cancer or melanoma. (A) presents the hazard ratios among non-Hispanic Whites overall. (B) presents the hazard ratios for non-Hispanic Blacks. (C) presents the hazard ratios for Hispanics. (D) presents the hazard ratios among non-Hispanic Whites, excluding individuals who died within 2 years of follow-up. (E) presents the hazard ratios among non-Hispanic Blacks, excluding individuals who died within 2 years of follow-up. (F) presents the hazard ratios among Hispanics, excluding individuals who died within 2 years of follow-up. Please note that hazard ratios for BMI groups for all subjects and healthy, never-smokers are relative to different reference groups and thus may not be comparable.</p
Antihistamine Therapy and Bone Mineral Density: Analysis in a Population-Based US Sample
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