2F ORAL ABSTRACTS: POPULATION HEALTH RESEARCH

Monday, October 24, 2016: 4:00 PM - 5:30 PM
Bayshore Ballroom Salon F, Lobby Level (Westin Bayshore Vancouver)
Moderator:

Beate Sander, PhD
Public Health Ontario
Scientist

4:00 PM
2F-2

Huei-Ting Tsai, PhD1, George Philips, MD, MPH2, Ruth Pfeiffer, PhD3, David Penson, M.D.4, Alex Fu, PhD1, Yingjun Zhou, MS1 and Arnold Potosky, PhD1, (1)Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC, (2)Department of Medicine, Georgetown University Medical Center, Georgetown University, Washington D.C., USA, Washington, DC, (3)National Cancer Institute, Rockville, MD, (4)Vanderbilt University, Nashville, TN
Purpose: To provide population-based data for a long-standing debate on comparative survival benefit of intermittent and continuous androgen deprivation therapy (IADT versus CADT) among patients with advanced prostate cancer (PCa).

Methods: Using the linked SEER-Medicare data, we conducted a retrospective cohort study of 5,377 advanced PCa patients aged 66 or older diagnosed between 2002-2011 receiving ADT as primary treatment. The study cohort included two patient subgroups: 3,513 men with incident metastatic PCa at diagnosis and 1,864 men with salvage ADT after initial curative-intent therapy for localized disease (non-metastatic group). We obtained 5-year mortality outcomes, including all-cause and PCa death for the metastatic group and non-PCa and cardiovascular death for the non-metastatic group, via state death certificate data obtained by the SEER program. The CADT group included men who continued receiving ADT without any treatment gaps longer 3 months. IADT group included men who had a gap of more than 3 months between two subsequent ADT injections with the first gap within 18 months after ADT initiation and at least one PSA measurement or physician visit between the two ADT injections. We used Cox-proportional hazard models to estimate hazard ratios and 95% confidence intervals of each survival outcome between IADT versus CADT group. We also conducted matched propensity score analysis to address potential bias in patient selection for treatment in an observational setting. 

Results: Compared with the CADT group, men in IADT group had similar 5-year risk of all-cause death (HR=0.90, 95%C.I. = 0.82, 1.00, p=0.05) but a lower risk of PCa death (HR= 0.80, 95%C.I. = 0.70, 0.92, p=0.002). Among non-metastatic patients, we found a lower risk of non-prostate cancer (HR=0.59, 95%C.I. = 0.34, 1.01, p=0.06) and cardiovascular death (HR=0.77, 95%C.I. = 0.51, 1.17, p=0.22) in IADT group than in CADT group although the difference did not reach statistical significance. We obtained similar estimates in our sensitivity analysis. 

Conclusions: IADT for elderly men with advanced PCa provides similar overall survival benefit as CADT and may potentially reduce PCa death in men newly diagnosed with metastatic PCa. Among men receiving salvage ADT for managing localized disease progression, IADT and CADT may have similar risk of cardiovascular and non-prostate cancer death. This information may facilitate decision-making regarding use of IADT or CADT for treating advanced PCa.

4:15 PM
2F-3

Linwei Wang, MSc, Dimi Panagiotoglou, PhD, Jeong Eun Min, MSc, Kora Debeck, PhD, M-J Milloy, PhD, Thomas Kerr, PhD, Kanna Hayashi, PhD and Bohdan Nosyk, PhD, BC Centre for Excellence in HIV/AIDS, Vancouver, BC, Canada
Purpose:

People who inject drugs (PWID) face multiple barriers to healthcare due to substance use, medical comorbidity and social disadvantage. We evaluated access to health and social services by three of the most prevalent comorbid conditions observed among PWID, including HIV, hepatitis C (HCV) and mental health in an urban setting in Canada.

Method:

Data were derived from prospective cohorts of community-recruited PWID between 2005 and 2015. HIV and HCV diagnoses were based on lab tests, while mental health conditions and inability to access health and social services (barriers to access) were determined by participants’ self-report. We employed generalized linear mixed models controlling for confounders to examine associations between health conditions and barriers to access. Comorbid conditions were classified in several ways to examine cumulative effects and interactions between conditions: 1) occurrence of each health condition, adjusting for the other two; 2) the number of health conditions per individual; 3) eight mutually exclusive patient subgroups.

Result:

Among 2,494 participants, 1,632 (65.4%) reported barriers to access at least once over a median of six (IQR: 2, 11) semi-annual follow-up assessments. Mental health conditions were independently associated with increased barriers to access (adjusted Odds Ratio (aOR): 1.45, 95% Confidence Interval (CI): 1.32, 1.58), while HIV was not (aOR: 0.96, 95% CI: 0.85, 1.08), and HCV was associated with decreased barriers to access (aOR: 0.80, 95% CI: 0.69, 0.93). The associations between mental health conditions and barriers to access were consistent among PWID without infections (aOR: 1.35, 95% CI: 1.10, 1.65), with HCV (aOR: 1.55, 95% CI: 1.37, 1.75), and HCV and HIV co-infection (aOR: 1.36, 95% CI: 1.15, 1.60). 

Conclusion:

We found a large proportion of PWID reported barriers to access, and mental health conditions were associated with increased barriers. Targeted strategies to seek and treat mental health conditions in settings that serve PWID population, and assist PWID with mental health conditions navigate the healthcare system may improve the efficiency and effectiveness of publicly-funded health and social services.

4:30 PM
2F-4

Malek B. Hannouf, Ph.D., London Health Sciences Centre, London, ON, Canada, Eric Winquist, MD, MSc, Department of Oncology, Western University, London, ON, Canada, Salah Mahmud, MD, Ph.D., Department of Epidemiology and Cancer Registry, CancerCare Manitoba, Winnipeg, MB, Canada, Muriel Brackstone, MD, Ph.D, FRCSC, Deparment of Oncology and Surgery, Western University, London, ON, Canada, Sisira Sarma, Ph.D., Department of Epidemiology and Biostatistics, Western University, London, ON, Canada, George B. Rodrigues, MD, FRCPC, Ph.D., London Regional Cancer Program, London, ON, Canada, Peter Rogan, Ph.D., Department of Biochemistry & Computer Science, Western University, London, ON, Canada and Gregory S. Zaric, Ph.D., Ivey Business School, Western University, London, ON, Canada
Purpose: Several genomic tests have been developed to identify the PT in CUP. However, the value of identifying the PT in clinical practice for CUP patients remains questionable and difficult to prove in randomized trials. We aimed to estimate the clinical and economic impact of PT identification in CUP using a retrospective matched cohort study.

Methods: We used the Manitoba Cancer Registry to identify all patients initially diagnosed with metastatic cancer between 2002 and 2011 who survived at least 6 months following initial diagnosis. We defined patients to have CUP if the PT was found 6 months or more after initial diagnosis or never found during the course of disease. Otherwise, we considered patients to have metastatic cancer of known PT (CKP). We linked all patients with Manitoba Health administrative databases to estimate direct costs of healthcare utilization based on a phase-of-care approach. We used propensity-score matching technique to match each CUP patient with a CKP patient based on all known clinicopathologic characteristics. We compared treatments, two-year survival and costs of healthcare utilization between the two patient groups and assessed treatment effect on overall survival (OS) using Cox regression adjustment.

Results: Of the 5,839 patients found diagnosed with metastatic cancer, 395 had CUP (6.8%). A 1:1 matching created a matched group of 395 patients with CKP. Patients with CUP compared to CKP counterparts were less likely to receive surgery, radiotherapy, hormone therapy and targeted therapy, and more likely to receive toxic empiric chemotherapeutic agents. Having CUP was associated with reduced OS (HR= 1.31 [95%CI= 1.1-1.58] p= 0.005) but lost statistical significance with adjustment for treatment differences. Compared to CKP patients, CUP patients had an increase of $3,850CAD in the mean cost of initial diagnostic workup before diagnosis and $1,100CAD in the mean cost of end-of-life. CUP patients also had a reduction of $334CAD in the mean cost of initial cancer care after diagnosis and $4,200CAD in the mean cost of continuing cancer care.

Conclusion: Compared to CKP patients, CUP patients received fewer cancer treatments, had reduced OS, and used more healthcare resources for diagnostic workup and end-of-life but less healthcare resources for cancer care. Identifying the PT in CUP patients might enable use of more effective therapies, improve OS and more efficiently allocate healthcare resources.

4:45 PM
2F-5

Tamar Krishnamurti, PhD1, Hyagriv Simhan, MD, MS2, Alexander Davis, PhD3, Gabrielle Wong-Parodi, PhD1, Octavio Mesner, MS1, Baruch Fischhoff, PhD1 and Yoel Sadovsky, MD2, (1)Carnegie Mellon University, Pittsburgh, PA, (2)Magee-Women's Research Institute, Pittsburgh, PA, (3)Department of Engineering & Public Policy, Carnegie Mellon University, Pittsburgh, PA
Purpose: The burden of adverse birth outcomes to the healthcare system and society is great, with a US preterm birth prevalence rate over 11% and a conservative annual $26.2B estimate of associated costs. Here, we assessed the effectiveness of a personalized pregnancy risk reduction smartphone app at engaging a high risk patient population.

Method: The MyHealthyPregnancy smartphone app is a pregnancy tool that delivers patient-specific risk feedback to its users, including fetal health monitoring through a fetal “kick” counter, pregnancy education, behavioral nudges (e.g. reminders), and access to critical resources, including transportation to routine prenatal appointments, and real-time alerts to medical staff when patients report high-risk events (e.g. suicidal ideation), or clinical indicators (e.g. preterm contractions). With the goal of measuring participants’ voluntary use of the app, we recruited a proof-of-concept patient sample (n = 16) from the Magee-Womens Hospital outpatient clinic (Pittsburgh, PA, USA) for a three-month participation period, drawing women across pregnancy trimesters. 

Result: Participants demonstrated a high level of engagement with the app, with an attendance rate of 85.7% at routine prenatal appointments, compared with 50% for the non-participant clinic population. Attendance was even higher (91.8%) among those who scheduled transportation to their appointments through the app. While no participants reported behavioral risk factors at a baseline enrollment interview, real-time data collection through the app was able to identify cases of intimate partner violence, depression, routine smoking, and marijuana use. 

Conclusion: These findings suggest that the MyHealthyPregnancy app is a helpful means of communicating and gathering personal health risk information. It provides an easily accessible format for detection of changes in risk, such as intimate partner violence, at more frequent intervals than is possible by routine medical care. Moreover, by increasing appointment attendance rates, it shows potential for significant savings to the healthcare system.

5:00 PM
2F-6

Richard K. Zimmerman, MD, MPH, MS1, Mary Patricia Nowalk, PhD1, Chyongchiou Jeng Lin, PhD2 and Song Zhang, MS3, (1)University of Pittsburgh School of Medicine, Pittsburgh, PA, (2)University of Pittsburgh, School of Medicine, Dept of Family Medicine, Pittsburgh, PA, (3)Pittsburgh, PA
Purpose: To increase pneumococcal vaccination rates among adults 19-64 years considered to be at high risk of pneumococcal disease because of the presence of one or more chronic medical conditions.

Methods: The 4 Pillars™ Immunization Toolkit (Toolkit) is a compilation of evidence-based strategies, resources, and step-by-step guidance for making office systems changes to increase adult vaccination and was the foundation of the intervention.  The intervention took place in 18 primary care practices in Pittsburgh, PA.  Baseline year was 6/1/2012-5/31/2013. In a randomized controlled cluster trial in Year 1 (6/1/2013-5/31/2014), 10 sites received the intervention and in a pre-post study in Year 2 (6/1/2014-1/31/2015), the control sites and 4 Year 1 intervention sites received the intervention and the remaining 6 sites were in maintenance.  The analytical dataset included patients with at least one office visit in each year. Patients were 19-64 years and classified as high risk based upon ICD9 codes and were grouped into those with diabetes, lung disease, heart disease, and others.  Pneumococcal polysaccharide vaccine (PPSV) vaccination rates among all eligible patients at the end of baseline and at the end of the 2-year intervention are reported.

Result: 4,737 high risk patients were identified with a mean age at baseline of 52 years; 8.2% were non-white and 54.2% were women, 65.4% were commercially insured, 42.2% had diabetes, 11.3% had lung disease and 12.8% had heart disease.  43.1% (2042/4737) high risk patients had received the 23-valent PPSV at the end of baseline.  Among remaining 2695 eligible patients, 596 (22.1%) received the vaccine during the study period for a final cumulative vaccination rate of 55.7%. Patients with diabetes were more frequently vaccinated with PPSV at the end of baseline (52.1%) and at the end of the intervention (66.2%) than patients with chronic lung or chronic heart disease.  In logistic regression, high risk individuals were more likely to be vaccinated if they were older, commercially insured and had diabetes.

Conclusion: At the end of two years, PPSV vaccination rates among high risk adults under age 65 years were close to the national goal of 60%. Patients with diabetes were more likely to receive PPSV than those with other high risk conditions.