ACAbigail Crocker

Abigail Crocker

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

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Previous Organizations / Institutes

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Abigail Crocker has a total of 104 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Integrating behavioural health and primary care: qualitative findings on contextual factors that influence integration

    by Jennifer Jewiss, Lisa W Natkin, Kelly Clark/Keefe, Abigail Crocker, Julie A Welkowitz

    Background: Integrating behavioural health care into primary care practices may increase patients’ access to behavioural health services and improve health outcomes. However, few studies have explored factors that influence integration processes. Objective: We sought to better understand contextual factors that support or impede behavioural health integration in primary care practices. Methods: We conducted 71 semi-structured interviews with providers, staff, and leaders from eight primary care practices in the United States with integrated behavioural health services, which were participating in a randomized control, pragmatic trial: Integrating Behavioural Health and Primary Care. Practices were selected for diversity on geographic location, size, ownership, and experience with integration. We conducted a thematic analysis of the qualitative data derived from the interviews. Results: We identified four categories of contextual factors influencing behavioural health integration: leadership commitment to integration, financial considerations, workflow and communication systems, and providers’ perspectives on integration and team-based healthcare. Supportive factors included leaders’ commitment to integration, adequate staffing, customized communication and workflow systems, collaborative practice culture, and healthy working relationships amongst providers. Impediments included staffing issues and payment models that do not reimburse for activities required to support integrated care. Conclusion: Interviewees described various benefits of integration, including providers feeling better equipped to address patients’ needs due to collaboration between medical and behavioural providers and resulting interdisciplinary learning. Given concerns about provider burnout, this finding warrants further study.


  • Open Access

    Intraclass Correlation and Variance in the Characteristics of Primary Care Patients Managing Chronic Medical and Behavioral Conditions

    by Abigail Crocker, Lisa W. Natkin, Peter Callas, Levi Bonnell, Jessica Clifton, Juvena Hitt, Benjamin Littenberg

    To avoid statistical errors, researchers who recruit patients from selected medical practices and analyze them at the individual level need to account for the clustered nature of their sample. This is most often done using the intraclass correlation coefficients (ICCs), a measure of how strongly subjects recruited from the same cluster (in this case patients from a clinic) resemble each other. The aim is to support the design of cluster-randomized studies by supplying estimates of variance and ICC of various measures using a population of patients from multiple primary care clinics. ICCs were extracted from a large cluster-randomized pragmatic clinical trial of adult primary care patients managing multiple chronic conditions, the Integrating Behavioral Health and Primary Care study (IBH-PC). IBH-PC collected demographics and patient-reported health outcomes on over 3,000 adults from 44 primary care practices in 13 states across the US. We present estimates of the standard deviation and ICC for gender, race, ethnicity, marital status, employment, income, education, social determinants of health, PROMIS-29 functional status, Duke Activity Status Index (DASI), nine-item Patient Health Questionnaire (PHQ-9) depression score, Generalized Anxiety Disorder (GAD-7) anxiety score, Asthma Symptom Utility Index, restricted activity days, medication adherence, health care visits in the past month, emergency room visits in the past year, hospital days in the past year, perception of quality and patient-centeredness of care, alcoholic drinks per month, and the GAIN substance use disorder screener. ICCs varied broadly with the highest values found for race and income and the lowest for short-term estimates of the GAIN. These values can be used to inform the design, especially power estimates and sample size requirements, of future studies.


  • Open Access

    Integrating behavioral health & primary care for multiple chronic diseases: Clinical trial of a practice redesign toolkit

    by Benjamin Littenberg, Paula Reynolds, Lisa Natkin, Constance van Eeghen, Peter Callas, Wilson Pace, Gail Rose, Juvena Hitt, Abigail Crocker, Daniel Mullin, et al.

    Context: Most patients in need of behavioral health (BH) care are seen in primary care, which often has difficulty responding. Some practices integrate behavioral health care (IBH), with medical and BH providers at the same location, working as a team. However, it is difficult to achieve high levels of integration. Objective: Test the effectiveness of a practice intervention designed to increase BH integration. Study Design: Pragmatic, cluster-randomized controlled trial. Setting: 43 primary care practices with on-site BH services in 13 states. Population: 2,460 adults with multiple chronic medical and behavioral conditions. Intervention: 24-month practice change process including an online curriculum, a practice redesign and implementation workbook, remote quality improvement coaching services, and an online learning community. Outcomes: Primary outcomes were changes in the 8 Patient-Reported Outcomes Measurement Information System (PROMIS-29) domain scores. Secondary outcomes were changes in medication adherence, self-reported healthcare utilization, time lost due to disability, cardiovascular capacity, patient centeredness, provider empathy, and several condition-specific measures. A sample of practice staff completed the Practice Integration Profile at each time point to estimate the degree of BH integration in that site. Practice-level case studies estimated the typical costs of implementing the intervention. Results: The intervention had no significant effect on any of the primary or secondary outcomes. Subgroup analyses showed no convincing patterns of effect in any populations. COVID-19 was apparently not a moderating influence of the effect of the intervention on outcomes. The intervention had a modest effect on the degree of practice integration, reaching statistical significance in the Workflow domain. The median cost of the intervention was $18,204 per practice. In post-hoc analysis, level of BH integration was associated with improved patient outcomes independent of the intervention, both at baseline and longitudinally. Conclusions: The specific intervention tested in this study was inexpensive, but had only a small impact on the degree of BH integration, and none on patient outcomes. However, practices that had more integration at baseline had better patient outcomes, independent of the intervention. Although this particular intervention was ineffective, IBH remains an attractive strategy for improving patient outcomes.


  • Open Access

    Integrating Behavioral Health and Primary Care (IBH-PC) to improve patient-centered outcomes in adults with multiple chronic medical and behavioral health conditions: study protocol for a pragmatic cluster-randomized control trial

    by Abigail M. Crocker, Rodger Kessler, Constance van Eeghen, Levi N. Bonnell, Ryan E. Breshears, Peter Callas, Jessica Clifton, William Elder, Chet Fox, Sylvie Frisbie, et al.

    Background: Chronic diseases that drive morbidity, mortality, and health care costs are largely influenced by human behavior. Behavioral health conditions such as anxiety, depression, and substance use disorders can often be effectively managed. The majority of patients in need of behavioral health care are seen in primary care, which often has difficulty responding. Some primary care practices are providing integrated behavioral health care (IBH), where primary care and behavioral health providers work together, in one location, using a team-based approach. Research suggests there may be an association between IBH and improved patient outcomes. However, it is often difficult for practices to achieve high levels of integration. The Integrating Behavioral Health and Primary Care study responds to this need by testing the effectiveness of a comprehensive practice-level intervention designed to improve outcomes in patients with multiple chronic medical and behavioral health conditions by increasing the practice’s degree of behavioral health integration. Methods: Forty-five primary care practices, with existing onsite behavioral health care, will be recruited for this study. Forty-three practices will be randomized to the intervention or usual care arm, while 2 practices will be considered “Vanguard” (pilot) practices for developing the intervention. The intervention is a 24-month supported practice change process including an online curriculum, a practice redesign and implementation workbook, remote quality improvement coaching services, and an online learning community. Each practice’s degree of behavioral health integration will be measured using the Practice Integration Profile. Approximately 75 patients with both chronic medical and behavioral health conditions from each practice will be asked to complete a series of surveys to measure patient-centered outcomes. Change in practice degree of behavioral health integration and patient-centered outcomes will be compared between the two groups. Practice-level case studies will be conducted to better understand the contextual factors influencing integration. Discussion: As primary care practices are encouraged to provide IBH services, evidence-based interventions to increase practice integration will be needed. This study will demonstrate the effectiveness of one such intervention in a pragmatic, real-world setting. Trial registration: ClinicalTrials.gov NCT02868983. Registered on August 16, 2016.


  • Open Access

    Integrating Behavioral Health and Primary Care (IBH-PC) to improve patient-centered outcomes in adults with multiple chronic medical and behavioral health conditions: study protocol for a pragmatic cluster-randomized control trial

    by Abigail M Crocker, Rodger Kessler, Constance van Eeghen, Levi N Bonnell, Ryan E Breshears, Peter Callas, Jessica Clifton, William Elder, Chet Fox, Sylvie Frisbie, et al.

    BackgroundChronic diseases that drive morbidity, mortality, and health care costs are largely influenced by human behavior. Behavioral health conditions such as anxiety, depression, and substance use disorders can often be effectively managed. The majority of patients in need of behavioral health care are seen in primary care, which often has difficulty responding. Some primary care practices are providing integrated behavioral health care (IBH), where primary care and behavioral health providers work together, in one location, using a team-based approach. Research suggests there may be an association between IBH and improved patient outcomes. However, it is often difficult for practices to achieve high levels of integration. The Integrating Behavioral Health and Primary Care study responds to this need by testing the effectiveness of a comprehensive practice-level intervention designed to improve outcomes in patients with multiple chronic medical and behavioral health conditions by increasing the practice’s degree of behavioral health integration.Methods43 primary care practices, with existing onsite behavioral health care, will be randomized to the intervention or usual care arm. The intervention is a 24-month supported practice change process including an online curriculum, a practice redesign and implementation workbook, remote quality improvement coaching services, and an online learning community. Each practice’s degree of behavioral health integration will be measured using the Practice Integration Profile. Approximately 75 patients with both chronic medical and behavioral health conditions from each practice will be asked to complete a series of surveys to measure patient-centered outcomes. Change in practice degree of behavioral health integration and patient-centered outcomes will be compared between the two groups. Practice-level case studies will be conducted to better understand the contextual factors influencing integration.DiscussionAs primary care practices are encouraged to provide IBH services, evidence-based interventions to increase practice integration will be needed. This study will demonstrate the effectiveness of one such intervention in a pragmatic, real-world setting.Trial registrationClinicalTrials.gov NCT02868983. Registered August 16, 2016. https://clinicaltrials.gov/ct2/show/NCT02868983

  • Open Access

    High prevalence of injection drug use and blood-borne viral infections among patients in an urban emergency department

    by Erik S Anderson, Carly Russell, Kellie Basham, Martha Montgomery, Helen Lozier, Abigail Crocker, Marisa Zuluaga, Douglas A E White

    The opioid epidemic has led to an increase in the number of persons who inject drugs, and this population accounts for 12% of new human immunodeficiency virus (HIV) and 60% of new hepatitis C virus (HCV) infections in the United States annually. While persons who inject drugs disproportionately utilize the emergency department (ED), accurate data is lacking on the prevalence and patterns of injection drug use, and prevalence of co-occurring HIV and HCV infections among ED patients. The primary outcome was to assess the prevalence of injection drug use and co-occurring HIV and HCV infection among patients presenting to an urban ED. This was a cross sectional study conducted at an urban ED, with an annual census of 65,000 visits. A closed-response questionnaire was developed based on publicly available validated surveys to assess patterns of injection drug use and HIV and HCV infection status, and administered by trained research assistants to all registered adult patients during 4-hour blocks of time. Of the 2,319 eligible patients, 2,200 (94.9%) consented and completed the survey. 241 (11.0%) had ever used injection drugs, 103 (4.7%) currently used injection drugs, and 138 (6.3%) formerly used injection drugs. White patients age 25 to 34 years and white patients age 55 to 64 years had the highest prevalence of current (25.6%) and former (27.1%) injection drug use, respectively. Persons who use injection drugs had a higher prevalence of HCV infection (52.7% vs. 3.4%) and HIV infection (6.2% vs. 1.8%) than the rest of the population. A high prevalence of ED patients report injection drug use, and this population self-reports a high prevalence of HIV and HCV infection. Emergency departments are in a unique position to engage with this population with regards to substance use treatment and linkage to care for HIV and HCV infection.


  • Molecular signatures suggest a major role for stromal cells in development of invasive breast cancer

    by Theresa Casey, Jeffrey Bond, Scott Tighe, Timothy Hunter, Laura Lintault, Osman Patel, Jonathan Eneman, Abigail Crocker, Jeffrey White, Joseph Tessitore, et al.

    Background Breast cancer invasion and metastasis involves both epithelial and stromal changes. Our objective was to delineate the pivotal role stroma plays in invasion by comparing transcriptomes among stromal and epithelial cells in normal tissue and invasive breast cancer. Methods Total RNA was isolated from epithelial and stromal cells that were laser captured from normal breast tissue (n = 5) and invasive breast cancer (n = 28). Gene expression was measured using Affymetrix U133A 2.0 GeneChips. Differential gene expression was evaluated and compared within a model that accounted for cell type (epithelial [E] versus stromal [S]), diagnosis (cancer [C] versus normal [N]) as well as cell type-diagnosis interactions. Results Compared to NE, the CE transcriptome was highly enriched with genes in proliferative, motility and ECM ontologies. Differences in CS and NS transcriptomes suggested that the ECM was being remodeled in invasive breast cancer, as genes were over-represented in ECM and proteolytic ontologies. Genes more highly expressed in CS compared to CE were primarily ECM components or were involved in the remodeling of ECM, suggesting that ECM biosynthesis and remodeling were initiated in the tumor stroma. Conclusion Based on identified molecular cross-talk between the two contiguous cell populations, a mechanistic model that spurs invasion is proposed, that shows breast cancer invasion proceeds through the acquisition of a motile phenotype in tumor epithelial cells and a reactive phenotype in cancer associated fibroblasts.


  • Cancer associated fibroblasts stimulated by transforming growth factor beta1 (TGF-β1) increase invasion rate of tumor cells: a population study

    by Theresa M. Casey, Jonathan Eneman, Abigail Crocker, Jeffrey White, Joseph Tessitore, Mary Stanley, Seth Harlow, Janice Y. Bunn, Donald Weaver, Hyman Muss, et al.

    Cancer associated fibroblasts (CAFs) are believed to promote tumor growth and progression. Our objective was to measure the effect of TGF-β1 on fibroblasts isolated from invasive breast cancer patients. Fibroblasts were isolated from tissue obtained at surgery from patients with invasive breast cancer (CAF; n = 28) or normal reduction mammoplasty patients (normal; n = 10). Myofibroblast activation was measured by counting cells immunostained for smooth muscle alpha actin (ACTA2) in cultures ± TGF-β1. Conditioned media (CM) was collected for invasion assays and RNA was isolated from cultures incubated in media ± TGF-β1 for 24 h. Q-PCR was used to measure expression of cyclin D1, fibronectin, laminin, collagen I, urokinase, stromelysin-1, and ACTA2 genes. Invasion rate was measured in chambers plated with MDA-MB-231 cells and exposed to CM in the bottom chamber; the number of cells that invaded into the bottom chamber was counted. Wilcox Rank Sum tests were used to evaluate differences in CAFs and normal fibroblasts and the effect of TGF-β1. There was no difference in percent myofibroblasts or invasion rate between normal and CAF cultures. However, TGF-β1 significantly increased the percent of myofibroblasts (P < 0.01) and invasion rate (P = 0.02) in CAF cultures. Stromelysin-1 expression was significantly higher in normal versus CAF cultures (P < 0.01). TGF-β1 significantly increased ACTA2 expression in both normal and CAF cultures (P < 0.01). Expression of fibronectin and laminin was significantly increased by TGF-β in CAF cultures (P < 0.01). CAFs were measurably different from normal fibroblasts in response to TGF-β1, suggesting that TGF-β stimulates changes in CAFs that foster tumor invasion.