Publications

BACKGROUND

Data abstraction, a critical systematic review step, is time-consuming and prone to errors. Current standards for approaches to data abstraction rest on a weak evidence base. We developed the Data Abstraction Assistant (DAA), a novel software application designed to facilitate the abstraction process by allowing users to (1) view study article PDFs juxtaposed to electronic data abstraction forms linked to a data abstraction system, (2) highlight (or "pin") the location of the text in the PDF, and (3) copy relevant text from the PDF into the form. We describe the design of a randomized controlled trial (RCT) that compares the relative effectiveness of (A) DAA-facilitated single abstraction plus verification by a second person, (B) traditional (non-DAA-facilitated) single abstraction plus verification by a second person, and (C) traditional independent dual abstraction plus adjudication to ascertain the accuracy and efficiency of abstraction.

METHODS

This is an online, randomized, three-arm, crossover trial. We will enroll 24 pairs of abstractors (i.e., sample size is 48 participants), each pair comprising one less and one more experienced abstractor. Pairs will be randomized to abstract data from six articles, two under each of the three approaches. Abstractors will complete pre-tested data abstraction forms using the Systematic Review Data Repository (SRDR), an online data abstraction system. The primary outcomes are (1) proportion of data items abstracted that constitute an error (compared with an answer key) and (2) total time taken to complete abstraction (by two abstractors in the pair, including verification and/or adjudication).

DISCUSSION

The DAA trial uses a practical design to test a novel software application as a tool to help improve the accuracy and efficiency of the data abstraction process during systematic reviews. Findings from the DAA trial will provide much-needed evidence to strengthen current recommendations for data abstraction approaches.

TRIAL REGISTRATION

The trial is registered at National Information Center on Health Services Research and Health Care Technology (NICHSR) under Registration # HSRP20152269: https://wwwcf.nlm.nih.gov/hsr_project/view_hsrproj_record.cfm?NLMUNIQUE… . All items from the World Health Organization Trial Registration Data Set are covered at various locations in this protocol. Protocol version and date: This is version 2.0 of the protocol, dated September 6, 2016. As needed, we will communicate any protocol amendments to the Institutional Review Boards (IRBs) of Johns Hopkins Bloomberg School of Public Health (JHBSPH) and Brown University. We also will make appropriate as-needed modifications to the NICHSR website in a timely fashion.

Statistical models in medical and population genetics typically assume that individuals assort randomly in a population. While this simplifies model complexity, it contradicts an increasing body of evidence of nonrandom mating in human populations. Specifically, it has been shown that assortative mating is significantly affected by genomic ancestry. In this work, we examine the effects of ancestry-assortative mating on the linkage disequilibrium between local ancestry tracks of individuals in an admixed population. To accomplish this, we develop an extension to the Wright-Fisher model that allows for ancestry-based assortative mating. We show that ancestry-assortment perturbs the distribution of local ancestry linkage disequilibrium (LAD) and the variance of ancestry in a population as a function of the number of generations since admixture. This assortment effect can induce errors in demographic inference of admixed populations when methods assume random mating. We derive closed form formulae for LAD under an assortative-mating model with and without migration. We observe that LAD depends on the correlation of global ancestry of couples in each generation, the migration rate of each of the ancestral populations, the initial proportions of ancestral populations, and the number of generations since admixture. We also present the first direct evidence of ancestry-assortment in African Americans and examine LAD in simulated and real admixed population data of African Americans. We find that demographic inference under the assumption of random mating significantly underestimates the number of generations since admixture, and that accounting for assortative mating using the patterns of LAD results in estimates that more closely agrees with the historical narrative.

BACKGROUND

Despite growing recognition of type 2 myocardial infarction (T2MI; related to supply/demand mismatch), little is known about its risk factors or its association with outcome.

METHODS

A single-center cohort of patients undergoing coronary or peripheral angiography with or without intervention was prospectively enrolled and followed for incident type 1 and T2MI, and major adverse cardiovascular events (MACE, a composite of all-cause death, nonfatal myocardial infarction [MI], heart failure, stroke, transient ischemic attack, peripheral arterial complication, and cardiac arrhythmia), as well. T2MI was adjudicated using criteria from the Third Universal Definition of MI. Baseline characteristics, blood samples, and angiography information were obtained. Major end points subsequent to first MI were assessed using landmark analyses to compare the rates of first events only where everyone with a prior history of any MACE before MI were censored and adjusted for follow-up times. Cox proportional hazard models were used for time-to-event analyses with age and sex forced into all models and additional covariates evaluated by using the stepwise option for the selection.

RESULTS

One thousand two hundred fifty-one patients were enrolled and followed for a median of 3.4 years. Of these patients, 152 (12.2%) had T2MI during follow-up; T2MI was frequently recurrent. Multivariable predictors of T2MI were older age, lower systolic blood pressure, history of coronary artery disease, heart failure, chronic obstructive pulmonary disease, diabetes mellitus, nitrate use, and elevated concentrations of glucose, N-terminal pro-B type natriuretic peptide, and cystatin C. Patients with T2MI had higher rates of subsequent adverse events than those without T2MI (per 100 person-years: MACE, 53.7 versus 21.1, P<0.001; all-cause death, 23.3 versus 3.3, P<0.001; cardiovascular death, 17.5 versus 2.6, P<0.001; heart failure events, 22.4 versus 7.4, P<0.001); these rates are similar to those seen in patients with type 1 MI. Incident diagnosis of T2MI strongly predicted risk for subsequent MACE (adjusted hazard ratio, 1.90; 95% confidence interval, 1.46-2.48; P<0.001), all-cause death (adjusted hazard ratio, 2.96; 95% confidence interval, 2.01-4.36; P<0.001), and cardiovascular death (adjusted hazard ratio, 2.16; 95% confidence interval, 1.36-3.43; P=0.001).

CONCLUSIONS

T2MI is common and associated with poor prognosis. Studies evaluating treatment strategies for management of T2MI are needed.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00842868.

INTRODUCTION

Gay and bisexual men and other men who have sex with men are among the small number of groups for whom HIV remains uncontrolled worldwide. Although there have been recent and notable decreases in HIV incidence across several countries, prevalence and incidence is consistently higher or rising among men who have sex with men when compared with other groups.

METHODS

In 2014, MSMGF (the Global Forum on MSM & HIV) conducted its third biennial Global Men's Health and Rights Study, an international, multilingual, web-based cross-sectional survey of men who have sex with men recruited through online convenience sampling. We tested hypothesized correlates (selected ) of successfully achieving each step along the HIV prevention and treatment continuum by fitting separate generalized estimating equation models adjusted for clustering by country in multivariate analyses. All models controlled for ability to meet basic financial needs, age, healthcare coverage, having a regular provider, region and country-level income.

RESULTS

Higher provider discrimination and sexual stigma were associated with lower odds of perceived access to services, service utilization and virologic suppression. Conversely, accessing services from community-based organizations focused on lesbian, gay, bisexual and transgender people; greater engagement in gay community; and comfort with healthcare providers were associated with higher odds of achieving steps along the prevention and treatment continuum.

CONCLUSIONS

To meet accelerated global HIV targets, global leaders must adopt a differentiated and bolder response, in keeping with current epidemiologic trends and community-based research. The HIV-related needs of gay and bisexual men and other men who have sex with men must be addressed openly, quickly and with sufficient resources to support evidence-based, community-led and human rights-affirming interventions at scale.