Papers by Jonathan Boyajian
Open Forum Infectious Diseases, Nov 1, 2018
Background. Older age has been associated with impaired CD4 recovery and a low CD4:CD8 ratio is a... more Background. Older age has been associated with impaired CD4 recovery and a low CD4:CD8 ratio is an independent predictor of non-AIDS morbidity/mortality. In this study we describe the overall comorbidity burden and assess factors associated with CD4:CD8 <1 among HIV+ older adults 60 years+ seen at CORE Center, Cook County Health and Hospital System; a safety-net health system. Methods. We evaluated demographic, clinical, and lab variables in all HIV+> 60 years who had at least 1 primary care visit from January 1, 2016 to May 31, 2017 at the RMR CORE center. Since HIV viremia is associated with CD4 recovery, analysis on CD4:CD8 ratios was restricted to the patients with viral suppression. Results. There were 809 patients with a median age of 63 (range: 60-89) years. Seventy-five percent were male, 74% black, 17% Hispanic and 8% white. Mean CD4 was 538 (+307) cells/mm; 107 (13%) had CD4 < 200 and 675 (84%) had undetectable HIVRNA (<40 copies/mL). 38% were HCV Ab+. Common comorbidities were hypertension 62%, COPD 23%, diabetes 22%, depression 17%, osteoarthritis 15%, neuropathy, chronic kidney disease (CKD) and coronary artery disease (CAD) 13% each. 50% had 1-2 comorbidities and 31% had >3 co-morbidities. Of the 675 patients with suppressed viremia, 470 patient (70%) had CD4:CD8 <1 and 245 (36%) had CD4:CD8 <0.5. Compared with patients with CD4:CD8 >1, patient with CD4:CD8 <1 had lower CD4 counts (451 vs. 739 cells/mm 3 ; P < 0.001), were less likely to have CD4 > 500 (35% vs. 75%; P <0.001), more likely to have CD4 <200 (13% vs. 1%; P <0.001), be male (82% vs. 60%; P < 0.001), HCVab+ (39% vs. 32%; P 0.05). They also trended to have more CAD 7% vs. 4% (P = 0.1) and more CKD 15% vs. 11% (P = 0.2). There was a high rate of multi-morbidity among older, predominantly ethnic minorities HIV-infected adults with 56% having >2 comorbidities. In the setting of viral suppression, 70% still had a CD4:CD8 ratio <1 which likely reflects the effects of older age, and lower CD4 nadir. This impaired immune restoration and co-morbidity burden portend a higher risk of non-AIDS morbidity and mortality in these patients and highlights the need for comprehensive care in HIV clinic settings. Disclosures.
A d-statistic for single-case designs that is equivalent to the usual between-groups d-statistic.... more A d-statistic for single-case designs that is equivalent to the usual between-groups d-statistic. Neuropsychological rehabilitation, (ahead-of-print), 1-26.
Meta-Analysis of the Autocorrelation in Single-Case Designs
PsycEXTRA Dataset, 2011
Colorectal cancer (CRC) is the second leading cause of cancer related death in the U.S. among men... more Colorectal cancer (CRC) is the second leading cause of cancer related death in the U.S. among men and women combined. In addition to the personal toll it takes, CRC is estimated to cost billions of dollars annually in medical costs. Due to the high rates and costs of CRC, a significant public health effort has been made to promote participation in screening, which has been shown to be effective at reducing CRC incidence and mortality rates; however, despite efforts to promote screening and research showing its effectiveness, screening rates remain low. Approaches to increasing screening participation focus on understanding the decision-making process people go through regarding screening. Health economics and health psychology provide two unique approaches to understanding this decision-making process. Health economics approaches model screening behavior as a function of the screening characteristics themselves while health psychology approaches model screening behavior as a functio...
Open Forum Infectious Diseases, 2018
Conclusion. Delay in ART initiation as well as risk factors for and presence of CVD were associat... more Conclusion. Delay in ART initiation as well as risk factors for and presence of CVD were associated with ED in HIV-infected persons. Mitigating risk factors and optimizing comorbidities is important to improve sexual health and reduce ED in HIV-infected persons. Disclosures. All authors: No reported disclosures. 603. Multi-morbidity and Impaired CD4/CD8 Ratios in Older Adults with Well-Controlled HIV
Ad-statistic for single-case designs that is equivalent to the usual between-groupsd-statistic
Neuropsychological Rehabilitation, 2013
We describe a standardised mean difference statistic (d) for single-case designs that is equivale... more We describe a standardised mean difference statistic (d) for single-case designs that is equivalent to the usual d in between-groups experiments. We show how it can be used to summarise treatment effects over cases within a study, to do power analyses in planning new studies and grant proposals, and to meta-analyse effects across studies of the same question. We discuss limitations of this d-statistic, and possible remedies to them. Even so, this d-statistic is better founded statistically than other effect size measures for single-case design, and unlike many general linear model approaches such as multilevel modelling or generalised additive models, it produces a standardised effect size that can be integrated over studies with different outcome measures. SPSS macros for both effect size computation and power analysis are available.
Multivariate Behavioral Research, 2011
Analyzing single-case designs: d, G, hierarchical models, Bayesian estimators, generalized additive models, and the hopes and fears of researchers about analyses
American Psychological Association eBooks, Jun 9, 2014
Linear and nonlinear growth models: Describing a Bayesian perspective
Journal of Consulting and Clinical Psychology, Oct 1, 2014
Conventional estimation of longitudinal growth models can produce inaccurate parameter estimates ... more Conventional estimation of longitudinal growth models can produce inaccurate parameter estimates under certain research scenarios (e.g., smaller sample sizes and nonlinear growth patterns) and thus lead to potentially misleading interpretations of results (i.e., interpreting growth patterns that do not reflect the population patterns). The current article used patterns of change in cigarette and alcohol abuse prevalence and depression levels to demonstrate an alternative method for estimating growth models more accurately under these conditions, namely, via the Bayesian estimation framework. This article acts as an introduction and tutorial for implementing Bayesian methods when examining growth or change over time, particularly nonlinear growth. The National Longitudinal Survey of Youth 1997 database was used to highlight different linear and nonlinear (quadratic and logistic) growth models via growth curve modeling (GCM) and growth mixture modeling (GMM). The specific focus was on changes in cigarette/alcohol consumption and depression throughout adolescence and young adulthood. Specifically, a nationally representative group of individuals between the ages of 12 and 16 years were assessed at 4 time-points for levels of cigarette consumption, alcohol use, and depression. The results for each example illustrated different patterns of linear and nonlinear growth via GCM and GMM through the versatile Bayesian estimation framework. Growth models may benefit from the Bayesian perspective by incorporating prior information or knowledge into the model, especially when sample sizes are small or growth is nonlinear. A step-by-step tutorial for assessing various growth models via the Bayesian perspective is provided as online supplemental material.
Multivariate Behavioral Research, Nov 30, 2011
American Journal of Emergency Medicine, Jul 1, 2019
General Hospital Psychiatry, 2019
Objective.-This study investigated patient-and area-level characteristics associated with adolesc... more Objective.-This study investigated patient-and area-level characteristics associated with adolescent emergency department (ED) patients' risk of subsequent ED visits for self-harm. Method.-Retrospective analysis of adolescent patients presenting to a California ED in 2010 (n=480,706) was conducted using statewide, all-payer, individually linkable administrative data. We examined associations between multiple predictors of interest (patient sociodemographic factors, prior ED utilization, and residential mobility; and area-level characteristics) and odds of a self-harm ED visit in 2010. Patients with any self-harm in 2010 were followed up over several years to assess predictors of recurrent self-harm. Results.-Self-harm patients (n=5,539) were significantly more likely than control patients (n=16,617) to have prior histories of ED utilization, particularly for mental health problems, substance abuse, and injuries. Residential mobility also increased risk of self-harm, but racial/ ethnic minority status and residence in a disadvantaged zipcode decreased risk. Five-year cumulative incidence of recurrent self-harm was 19.3%. Admission as an inpatient at index visit, *
Implementing the Class-Level Survey of Student Engagement: First Impressions and Findings
Assessment Update, 2010
Journal of Clinical Epidemiology, Aug 1, 2016
WRS had the idea for the study and prepared the first and last drafts of the article. WRS, DMR, a... more WRS had the idea for the study and prepared the first and last drafts of the article. WRS, DMR, and JGB conducted the statistical analyses. All authors have read and approved the final version of the manuscript. The Institutional Review Board waived review because this study used publicly available data without identifiers. The RCT reanalyzed in this article was published in 1987 before registration of trials was required.
Implementing the Class-Level Survey of Student Engagement: First Impressions and Findings
Assessment Update, 2010
Abstract: Introduction: The demand for organs currently far exceeds supply. Understanding individ... more Abstract: Introduction: The demand for organs currently far exceeds supply. Understanding individuals’ motivations for deciding whether to donate an organ from a deceased relative would guide outreach efforts.Methods: Focus group participants and literature were used to identify attributes to create a discrete choice experiment (DCE). Participants (N=86 ages 18 to 31 [mean=20.5]) were presented with 16 choices sets and asked to choose whether they would agree to donate a deceased relative’s organs. The choices contained attributes of the recipient (age, kidney’s lifespan, reason for failure, impact if not transplanted), the deceased donor (donor’s wishes and relationship to decision maker), and monetary incentives (amount, payer, payee). Conditional logit analysis was used to estimate the model, and latent class analysis identified two distinct groups of respondents.Results: The results suggest a strong preference for donating organs, with the age of the recipient, reason for recipi...
General Hospital Psychiatry, 2018
Objective.-This study investigated patient-and area-level characteristics associated with adolesc... more Objective.-This study investigated patient-and area-level characteristics associated with adolescent emergency department (ED) patients' risk of subsequent ED visits for self-harm. Method.-Retrospective analysis of adolescent patients presenting to a California ED in 2010 (n=480,706) was conducted using statewide, all-payer, individually linkable administrative data. We examined associations between multiple predictors of interest (patient sociodemographic factors, prior ED utilization, and residential mobility; and area-level characteristics) and odds of a self-harm ED visit in 2010. Patients with any self-harm in 2010 were followed up over several years to assess predictors of recurrent self-harm. Results.-Self-harm patients (n=5,539) were significantly more likely than control patients (n=16,617) to have prior histories of ED utilization, particularly for mental health problems, substance abuse, and injuries. Residential mobility also increased risk of self-harm, but racial/ ethnic minority status and residence in a disadvantaged zipcode decreased risk. Five-year cumulative incidence of recurrent self-harm was 19.3%. Admission as an inpatient at index visit, *
The American journal of emergency medicine, Jan 18, 2018
The quick sequential organ failure assessment score (qSOFA) has been proposed as a simple tool to... more The quick sequential organ failure assessment score (qSOFA) has been proposed as a simple tool to identify patients with sepsis who are at risk for poor outcomes. Its utility in the pre-hospital setting has not been fully elucidated. This is a retrospective observational study of adult patients arriving by ambulance in September 2016 to an academic emergency department in Fresno, California. The qSOFA score was calculated from pre-hospital vital signs. We investigated its association with sepsis, ED diagnosis of infection, and mortality. Of 2292 adult medical patients transported by ambulance during the study period, the sensitivity of qSOFA for sepsis and in-hospital mortality were 42.9% and 40.6%, respectively. Specificity of qSOFA for sepsis and mortality were 93.8% and 91.9%, respectively. Of those with an ED diagnosis of infection compared to all patients, qSOFA was more specific but less sensitive for sepsis. Increasing qSOFA score was associated with a discharge diagnosis of ...
Journal of Clinical Epidemiology, 2016
WRS had the idea for the study and prepared the first and last drafts of the article. WRS, DMR, a... more WRS had the idea for the study and prepared the first and last drafts of the article. WRS, DMR, and JGB conducted the statistical analyses. All authors have read and approved the final version of the manuscript. The Institutional Review Board waived review because this study used publicly available data without identifiers. The RCT reanalyzed in this article was published in 1987 before registration of trials was required.
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Papers by Jonathan Boyajian