Validating recommendations for coronary angiography following acute myocardial infarction in the elderly

Normand, Sharon‐Lise T.; Landrum, Mary Beth; Guadagnoli, Edward; Ayanian, John Z.; Ryan, Thomas J.; Cleary, Paul D.; McNeil, Barbara J.

doi:10.1016/s0895-4356(00)00321-8

Cited by 1,040 publications

(785 citation statements)

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“…All confounders examined in this study displayed a standardized difference of the mean of less than 10%, indicating balanced levels of the confounders between alcohol flushers and non-flushers. [36][37][38] Supplemental Table 1 also presents findings indicating that the prevalence of alcohol flushing was relatively similar among all age groups, whereas age was associated with alcohol consumption. In addition, alcohol flushing was very closely related with alcohol consumption and associated phenotypes, including AST, ALT, and GGT especially in men.…”

Section: Discussionmentioning

confidence: 99%

“…It has been suggested that a standardized difference of <10% likely denotes a negligible imbalance. [36][37][38] We then analyzed the association of alcohol consumption and associated phenotypes, such as AST, ALT, and GGT, with alcohol flushing status to determine whether alcohol flushing status was a good predictor of alcohol consumption. For log-transformed variables, mean differences on the log scale were converted to percentage differences.…”

Section: Statistical Analysesmentioning

confidence: 99%

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Alcohol and coronary artery calcification: an investigation using alcohol flushing as an instrumental variable

et al. 2017

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Section: Discussionmentioning

confidence: 99%

Section: Statistical Analysesmentioning

confidence: 99%

Alcohol and coronary artery calcification: an investigation using alcohol flushing as an instrumental variable

et al. 2017

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“…To assess covariate balance, we computed the standardized difference (d) for each of the characteristics described above before and after propensity-score adjustment. A general rule of thumb is that a standardized difference greater than 10 represents meaningful imbalance in a given covariate [20][21][22]. …”

Section: Discussionmentioning

confidence: 99%

Virginity Pledges Among the Willing: Delays in First Intercourse and Consistency of Condom Use

Martino

Elliott

Collins

et al. 2008

Journal of Adolescent Health

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Purpose-We examine longitudinal relationships between virginity pledging in adolescence and both sexual initiation and condom use. Prior studies have had mixed results and may not adequately control for pre-pledge differences between pledgers and non-pledgers.Methods-Data came from a national sample of 12-17 year olds surveyed in 2001 and reinterviewed 1 and 3 years later. Logistic regression models estimated the association between making a pledge and each outcome. Selection bias was reduced through propensity-score weighting and a rich set of demographic and psychosocial covariates.Results-Pledgers and non-pledgers differed substantially in pre-existing characteristics. However, after propensity-weighting and statistical controls, pledging was still associated with delayed intercourse. We estimate that in the absence of pledging 42.4% of virgins with characteristics indicating an inclination to pledge initiate intercourse within 3 years; in the presence of the pledge, 33.6%of such youth initiate intercourse. Among those who had sex during this period, pledging was unassociated with condom use. Among those who did not have sex during this period, pledging was unassociated with engagement in noncoital sexual behavior.Conclusions-Making a virginity pledge appears to be an effective means of delaying sexual intercourse initiation among those inclined to pledge without influencing other sexual behavior; pledging does not appear to affect sexual safety among pledgers who fail to remain abstinent.Nearly 800,000 teenagers become pregnant in the U.S. each year [1] and half of the approximately 19 million new STD infections diagnosed annually are among youth 15 to 24 years old [ 2]. Unplanned pregnancies and STDs are more common among those who begin sexual activity earlier [3]. Delaying sexual activity might therefore have important public health consequences.One approach to delaying sexual activity is the virginity pledge -a public declaration to abstain from sex until marriage. The first virginity pledge program was True Love Waits, founded by the Southern Baptist Church in 1993. The movement has since grown to include hundreds of churches, schools, and colleges across the country. Among adolescents in the United States, it is estimated that 23% of females and 16% of males have made a virginity pledge [4]. From a theoretical perspective, pledging may work by enhancing social norms to abstain from sex [ 5]; pledgers may believe, more so than others, that they will be held responsible to their peers or important adults to follow through on their public commitment.Correspondence regarding this manuscript can be sent to Steven C. Martino, RAND, 4570 Fifth Avenue, Suite 600, Pittsburgh, PA 15213-2665. Tel: 412-683-2300, ext. 4629. Fax: 412-683-2800 Through processes of cognitive dissonance or self-perception [6][7], pledging may also lead youth to internalize the commitment or values expressed in the pledge.Although these programs may delay sex, those who make a virginity pledge but fail to keep it may actually i...

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“…We acknowledge that this is somewhat oversimplified relative to the number of variables included when the propensity adjustment is applied in practice; and thus, the impact of just one omitted confound could be overstated. For example, studies of cardiovascular disease have included considerably more variables in the propensity score: 18 variables (Grzybowski et al, 2003), 34 variables (Gum et al, 2001) and 102 variables (Normand 2001). Nevertheless, when one large, time-varying confounding variable was omitted from the propensity score in the simulation study, the parameter estimate resulted in substantial bias, reduced coverage probability, and inflated type I error rates.…”

Section: Discussionmentioning

confidence: 99%

Quintile stratification based on a misspecified propensity score in longitudinal treatment effectiveness analyses of ordinal doses

Leon¹,

Hedeker²

2007

Computational Statistics & Data Analysis

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SummaryThe propensity adjustment provides a strategy to reduce the bias in treatment effectiveness analyses that compare non-equivalent groups such as seen in observational studies (Rosenbaum and Rubin, 1983). The objective of this simulation study is to examine the effect of omitting confounding variables from the propensity score on the quintile-stratified propensity adjustment in a longitudinal study. The primary focus was the impact of a misspecified propensity score on bias. Three features of the omitted confounding variables were examined: type of predictor variable (binary vs. continuous), constancy over time (time-varying vs. time-invariant), and magnitude of the association with treatment and outcome (null, small, and large odds ratios). The simulation results indicate that omission of continuous, time-varying confounders that are strongly associated with treatment and outcome (i.e., an odds ratio of 1.75) adversely impacts bias, coverage, and type I error. Omitted timevarying continuous variables had somewhat more effect on bias than omitted binary variables. Timeinvariant confounding variables that are not included in the propensity score have a much less effect on results. This evaluation only examined continuous treatment effectiveness outcomes and the propensity scores used for stratification included just four variables. Relative to the use of the propensity adjustment in applied settings that typically comprise numerous potential confounding variables, the impact of one omitted continuous, time-varying confound in this simulation study could be overstated.

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Validating recommendations for coronary angiography following acute myocardial infarction in the elderly

Cited by 1,040 publications

References 27 publications

Alcohol and coronary artery calcification: an investigation using alcohol flushing as an instrumental variable

Alcohol and coronary artery calcification: an investigation using alcohol flushing as an instrumental variable

Virginity Pledges Among the Willing: Delays in First Intercourse and Consistency of Condom Use

Quintile stratification based on a misspecified propensity score in longitudinal treatment effectiveness analyses of ordinal doses

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