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High-dimensional longitudinal classification with the multinomial fused lasso

Adhikari, Samrachana; Lecci, Fabrizio; Becker, James T; Junker, Brian W; Kuller, Lewis H; Lopez, Oscar L; Tibshirani, Ryan J
We study regularized estimation in high-dimensional longitudinal classification problems, using the lasso and fused lasso regularizers. The constructed coefficient estimates are piecewise constant across the time dimension in the longitudinal problem, with adaptively selected change points (break points). We present an efficient algorithm for computing such estimates, based on proximal gradient descent. We apply our proposed technique to a longitudinal data set on Alzheimer's disease from the Cardiovascular Health Study Cognition Study. Using data analysis and a simulation study, we motivate and demonstrate several practical considerations such as the selection of tuning parameters and the assessment of model stability. While race, gender, vascular and heart disease, lack of caregivers, and deterioration of learning and memory are all important predictors of dementia, we also find that these risk factors become more relevant in the later stages of life.
PMID: 30701586
ISSN: 1097-0258
CID: 3626812

Conditionally Independent Dyads (CID) network models: A latent variable approach to statistical social network analysis

Dabbs, Beau; Adhikari, Samrachana; Sweet, Tracy
Latent variable network models that accommodate edge correlations implicitly, by assuming an underlying latent factor, are increasing in popularity. Although, these models are examples of what is a growing body of research, much of the research is focused on proposing new models or extending others. There has been very little work on unifying the models in a single framework. In this paper, we present a complete framework that organizes existing latent variable network models within an integrative generalized additive model. Our framework is called Conditionally Independent Dyad (CID) models, and includes existing network models that assume dyad (or edge) independence conditional on latent variables and other components in the model. We further discuss practical aspects of model fitting such as posterior parameter estimation via MCMC, identifiability of parameters, approaches to handle missing data and model selection via cross-validation, for the proposed additive CID models. Finally, by presenting several data examples, we illustrate the utility of the proposed framework and provide advice on selecting components for building new CID models.
SCOPUS:85087725183
ISSN: 0378-8733
CID: 4543952

Assessment of Community-Level Disparities in Coronavirus Disease 2019 (COVID-19) Infections and Deaths in Large US Metropolitan Areas

Adhikari, Samrachana; Pantaleo, Nicholas P; Feldman, Justin M; Ogedegbe, Olugbenga; Thorpe, Lorna; Troxel, Andrea B
PMCID:7388025
PMID: 32721027
ISSN: 2574-3805
CID: 4574042

A Latent Space Network Model for Social Influence

Sweet, Tracy; Adhikari, Samrachana
Social network data represent interactions and relationships among groups of individuals. One aspect of social interaction is social influence, the idea that beliefs or behaviors change as a result of one's social network. The purpose of this article is to introduce a new model for social influence, the latent space model for influence, which employs latent space positions so that individuals are affected most by those who are "closest" to them in the latent space. We describe this model along with some of the contexts in which it can be used and explore the operating characteristics using a series of simulation studies. We conclude with an example of teacher advice-seeking networks to show that changes in beliefs about teaching mathematics may be attributed to network influence.
PMID: 32221792
ISSN: 1860-0980
CID: 4368602

RAAS Inhibitors and Risk of Covid-19. Reply [Comment]

Reynolds, Harmony R; Adhikari, Samrachana; Iturrate, Eduardo
PMID: 33108107
ISSN: 1533-4406
CID: 4646512

Influence of the food environment on obesity risk in a large cohort of US veterans by community type

Rummo, Pasquale E; Kanchi, Rania; Adhikari, Samrachana; Titus, Andrea R; Lee, David C; McAlexander, Tara; Thorpe, Lorna E; Elbel, Brian
OBJECTIVE:The aim of this study was to examine relationships between the food environment and obesity by community type. METHODS:Using electronic health record data from the US Veterans Administration Diabetes Risk (VADR) cohort, we examined associations between the percentage of supermarkets and fast-food restaurants with obesity prevalence from 2008 to 2018. We constructed multivariable logistic regression models with random effects and interaction terms for year and food environment variables. We stratified models by community type. RESULTS:Mean age at baseline was 59.8 (SD = 16.1) years; 93.3% identified as men; and 2,102,542 (41.8%) were classified as having obesity. The association between the percentage of fast-food restaurants and obesity was positive in high-density urban areas (odds ratio [OR] = 1.033; 95% CI: 1.028-1.037), with no interaction by time (p = 0.83). The interaction with year was significant in other community types (p < 0.001), with increasing odds of obesity in each follow-up year. The associations between the percentage of supermarkets and obesity were null in high-density and low-density urban areas and positive in suburban (OR = 1.033; 95% CI: 1.027-1.039) and rural (OR = 1.007; 95% CI: 1.002-1.012) areas, with no interactions by time. CONCLUSIONS:Many healthy eating policies have been passed in urban areas; our results suggest such policies might also mitigate obesity risk in nonurban areas.
PMID: 38298108
ISSN: 1930-739x
CID: 5627212

Racial and ethnic determinants of psoriatic arthritis phenotypes and disease activity

Haberman, Rebecca H; Ahmed, Tasneem; Um, Seungha; Zhou, Ying Yin; Catron, Sydney; Jano, Kathryn; Felipe, Adamary; Eichman, Stephanie; Rice, Alexandra L; Lydon, Eileen; Moussavi, Sarah; Neimann, Andrea L; Reddy, Soumya M; Adhikari, Samrachana; Scher, Jose U
OBJECTIVE:Individuals of racially and ethnically diverse backgrounds are underrepresented in psoriatic arthritis (PsA) research/clinical trials, despite evidence that their disease presentation, severity and course may be distinct. Here we aim to describe how race, ethnicity and other socioeconomic factors inform disease characteristics in PsA. METHODS:817 consecutive patients with PsA from a large, diverse metropolitan area, were enrolled in an observational, longitudinal registry. Demographics, medical history, medication use, and psoriatic disease phenotype and activity were all recorded and analyzed. RESULTS:The population was 77.4% non-Hispanic White, 2.2% Black, 7.1% Asian, and 9.9% identified as other races or multiracial, and 11.8% identified as Hispanic. Hispanic and non-White individuals had higher tender joint counts (p= 0.033) with similar swollen joint counts (p= 0.308) and medication use (p= 0.171). They also had high rates of radiographic axial disease. Hispanic individuals were significantly more likely to have higher tender joint counts (p= 0.029), higher RAPID3 scores (p= 0.004), and moderate-severe psoriasis (p= 0.010) compared with non-Hispanic White individuals. CONCLUSION/CONCLUSIONS:In this diverse cohort, 22.6% of patients identified as underrepresented racial and/or ethnic groups, mostly Asian or Hispanic. Despite similar swollen joint counts and medication use, non-white individuals have higher tender joint counts compared with white individuals. Phenotypically, they also were more likely to have radiographic axial involvement. These findings may reflect differences in PsA presentation, experience and outcomes in individuals of various racial and ethnic groups, which need to be taken into consideration in clinical care and research design.
PMID: 38305279
ISSN: 1462-0332
CID: 5626902

Associations between PM2.5 and O3 exposures and new onset type 2 diabetes in regional and national samples in the United States

McAlexander, Tara P; Ryan, Victoria; Uddin, Jalal; Kanchi, Rania; Thorpe, Lorna; Schwartz, Brian S; Carson, April; Rolka, Deborah B; Adhikari, Samrachana; Pollak, Jonathan; Lopez, Priscilla; Smith, Megan; Meeker, Melissa; McClure, Leslie A
BACKGROUND:across three large samples in the US using a harmonized approach for exposure assignment and covariate adjustment. METHODS:. RESULTS:. Results in the Geisinger sample were null. VADR sample results evidenced nonlinear associations for both pollutants; the shape of the association was dependent on community type. CONCLUSIONS:and new onset T2D differed across three large study samples in the US. None of the results from any of the three study populations found strong and clear positive associations.
PMID: 37827369
ISSN: 1096-0953
CID: 5604692

Preoperative Risk Factors for Adverse Events in Adults Undergoing Bowel Resection for Inflammatory Bowel Disease: 15-Year Assessment of ACS-NSQIP

Fernandez, Cristina; Gajic, Zoran; Esen, Eren; Remzi, Feza; Hudesman, David; Adhikari, Samrachana; McAdams-DeMarco, Mara; Segev, Dorry L; Chodosh, Joshua; Dodson, John; Shaukat, Aasma; Faye, Adam S
IntroductionOlder adults with IBD are at higher risk for postoperative complications as compared to their younger counterparts, however factors contributing to this are unknown. We assessed risk factors associated with adverse IBD-related surgical outcomes, evaluated trends in emergency surgery, and explored differential risks by age.MethodsUsing the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database, we identified adults ≥18 years of age who underwent an IBD-related intestinal resection from 2005-2019. Our primary outcome included a 30-day composite of mortality, readmission, reoperation, and/or major postoperative complication.ResultsOverall, 49,746 intestinal resections were performed with 9,390 (18.8%) occurring among older adults with IBD. Nearly 37% of older adults experienced an adverse outcome as compared to 28.1% among younger adults with IBD (p<0.01). Among all adults with IBD, the presence of preoperative sepsis (aOR, 2.08; 95%CI 1.94-2.24), malnutrition (aOR, 1.22; 95%CI 1.14-1.31), dependent functional status (aOR, 6.92; 95%CI 4.36-11.57), and requiring emergency surgery (aOR, 1.50; 95%CI 1.38-1.64) increased the odds of an adverse postoperative outcome, with similar results observed when stratifying by age. Further, 8.8% of surgeries among older adults were emergent, with no change observed over time (p=0.16).DiscussionPreoperative factors contributing to the risk of an adverse surgical outcome are similar between younger and older individuals with IBD, and include elements such as malnutrition and functional status. Incorporating these measures into surgical decision-making can reduce surgical delays in older individuals at low-risk and help target interventions in those at high risk, transforming care for thousands of older adults with IBD.
PMID: 37410929
ISSN: 1572-0241
CID: 5539322

Neighborhood-Level Socioeconomic Status and Prescription Fill Patterns Among Patients With Heart Failure

Mukhopadhyay, Amrita; Blecker, Saul; Li, Xiyue; Kronish, Ian M; Chunara, Rumi; Zheng, Yaguang; Lawrence, Steven; Dodson, John A; Kozloff, Sam; Adhikari, Samrachana
IMPORTANCE/UNASSIGNED:Medication nonadherence is common among patients with heart failure with reduced ejection fraction (HFrEF) and can lead to increased hospitalization and mortality. Patients living in socioeconomically disadvantaged areas may be at greater risk for medication nonadherence due to barriers such as lower access to transportation or pharmacies. OBJECTIVE/UNASSIGNED:To examine the association between neighborhood-level socioeconomic status (nSES) and medication nonadherence among patients with HFrEF and to assess the mediating roles of access to transportation, walkability, and pharmacy density. DESIGN, SETTING, AND PARTICIPANTS/UNASSIGNED:This retrospective cohort study was conducted between June 30, 2020, and December 31, 2021, at a large health system based primarily in New York City and surrounding areas. Adult patients with a diagnosis of HF, reduced EF on echocardiogram, and a prescription of at least 1 guideline-directed medical therapy (GDMT) for HFrEF were included. EXPOSURE/UNASSIGNED:Patient addresses were geocoded, and nSES was calculated using the Agency for Healthcare Research and Quality SES index, which combines census-tract level measures of poverty, rent burden, unemployment, crowding, home value, and education, with higher values indicating higher nSES. MAIN OUTCOMES AND MEASURES/UNASSIGNED:Medication nonadherence was obtained through linkage of health record prescription data with pharmacy fill data and was defined as proportion of days covered (PDC) of less than 80% over 6 months, averaged across GDMT medications. RESULTS/UNASSIGNED:Among 6247 patients, the mean (SD) age was 73 (14) years, and majority were male (4340 [69.5%]). There were 1011 (16.2%) Black participants, 735 (11.8%) Hispanic/Latinx participants, and 3929 (62.9%) White participants. Patients in lower nSES areas had higher rates of nonadherence, ranging from 51.7% in the lowest quartile (731 of 1086 participants) to 40.0% in the highest quartile (563 of 1086 participants) (P < .001). In adjusted analysis, patients living in the lower 2 nSES quartiles had significantly higher odds of nonadherence when compared with patients living in the highest nSES quartile (quartile 1: odds ratio [OR], 1.57 [95% CI, 1.35-1.83]; quartile 2: OR, 1.35 [95% CI, 1.16-1.56]). No mediation by access to transportation and pharmacy density was found, but a small amount of mediation by neighborhood walkability was observed. CONCLUSIONS AND RELEVANCE/UNASSIGNED:In this retrospective cohort study of patients with HFrEF, living in a lower nSES area was associated with higher rates of GDMT nonadherence. These findings highlight the importance of considering neighborhood-level disparities when developing approaches to improve medication adherence.
PMCID:10722333
PMID: 38095897
ISSN: 2574-3805
CID: 5589372