Graduation Year

2020

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Epidemiology and Biostatistics

Major Professor

Anna R. Giuliano, Ph.D.

Co-Major Professor

Kevin E. Kip, Ph.D.

Committee Member

Henian Chen, Ph.D.

Committee Member

Richard R. Reich, Ph.D.

Committee Member

Susan T. Vadaparampil, Ph.D.

Keywords

Cancer Screening, Clinical Practice Guidelines, Geographic Information System, Healthcare Utilization, Hepatocellular Carcinoma, Viral Hepatitis, Trends

Abstract

Background: Birth cohort hepatitis C Virus (HCV) screening recommendations were issued by the Centers for Disease Control and Prevention (CDC) and United States Preventive Services Task Force (USPSTF) in 2012 and 2013, respectively. Despite this, studies have reported low HCV screening rates. Currently, the prevalence of HCV screening rates nationally is unknown and there are no in-depth studies that have evaluated the barriers or facilitators of HCV screening. Our study aimed to fill this gap by 1) conducting a systematic literature review to assess the national HCV screening prevalence, 2) evaluating temporal trends in HCV screening using a large academic center, and 3) identifying barriers and facilitators associated with HCV screening among average-risk baby boomers using geographical information system (GIS) analyses to assess spatial autocorrelation hot spots and cold spots for HCV screening by individual and population-based characteristics.

Methods: To accomplish our aims, 1) a systematic literature review was conducted using controlled vocabulary to ascertain the HCV screening prevalence in the U.S. by limiting our search to articles published between January 1, 2012 and March 14, 2019 to coincide with 2012 and 2013 CDC and USPSTF guidelines, respectively for one-time universal testing for HCV among baby boomers (adults born 1945–1965), 2) temporal analyses were conducted covering August 1, 2015 to July 31, 2019 time period for average-risk baby boomers using Cochrane-Armitage test for trend analysis and Joinpoint analysis, and 3) geospatial analyses using geographic information systems’ software were conducted to a) create choropleth maps for HCV antibody test orders and HCV antibody test completion percentages by zip code, b) to measure spatial autocorrelation and to conduct hot spot and cold spot analyses using Global Moran’s Index (GMI) and Getis-Ord GI*, respectively to assess differences in HCV antibody test ordering and HCV antibody test completion percentages using data from the University of South Florida (USF) Healthcare System covering the August 1, 2015 to July 31, 2019 time period among average-risk baby boomers, and c) to evaluate socio-demographic differences between individual and population-based characteristics within hot spot areas (i.e., zip codes with the highest HCV antibody test order and HCV antibody test completion percentages). Patient level data were derived from the USF Healthcare System for the August 1, 2015 to July 31, 2019 time period while population level data were from the American Community Survey (ACS) from the U.S. Census Bureau covering the 2013 to 2017 time period.

Results: For Aim 1, after de-duplication, 1,900 articles were identified using four databases (i.e., MEDLINE via PubMed, EMBASE, Web of Science, and the Cochrane Library) for the systematic literature review. After applying inclusion and exclusion criteria, eight articles remained, of which, five were experimental studies (i.e., two randomized clinical trials and three non-randomized trials) and three were observational studies. The risk of bias assessment and the meta-analysis evaluated RCTs and non-randomized trials (i.e., we did not include post-intervention HCV screening data) and observational studies together. We found marked variability in HCV screening estimates among average-risk based baby boomers with a range of 1.4% (95% CI: 1.1%–1.7%) to 12.8% (95% CI: 12.1%–13.5%). The risk of bias assessment revealed high variability in risk of bias. For Aim 2, temporal trends using electronic health records from a large academic center revealed that out of 120,645 opportunities to receive a HCV antibody screening order during 2015–2019, 6,333 HCV antibody orders were placed and of those orders, only 4,259 HCV antibody tests were completed by average-risk baby boomers. The trend by month for HCV ordering percentages of HCV antibody tests during this period of time and showed that the lowest HCV antibody order rate of 1.0% (95% confidence interval [CI]: 0.5%–1.4%) occurred in August 2015. In contrast, the highest HCV antibody order rate of 12.7% (95% CI: 11.4%–14.0%) occurred in May 2017. And by the end of the study period, the HCV antibody order rate was 4.2%. At the start of the period, the HCV screening percentage (HCV antibody test completion) was 0.6% (95% CI: 0.0%–0.9%) in August 2015, at its peak in May 2017, the HCV screening percentage reached 8.8% (95% CI: 7.6%–9.9%), and by the end of the study period, the HCV screening percentage declined to 2.1% (95% CI: 3.1%–2.6%) by July 2019. For Aim 3, spatial autocorrelation showed statistically significant clustering of HCV antibody test orders (GMI = 0.541096; p < 0.000001) and HCV antibody test completion (GMI = 0.445374; p < 0.000001). There were 26 hot spots for HCV antibody test orders among average-risk baby boomers and 22 hot spots were identified for average-risk baby boomers who completed an HCV antibody test. We found that HCV antibody order rates were variable (15.0% to 37.2%) among average-risk baby boomers by zip code within hot spot areas and similarly the HCV screening completion rates also differed ranging between 9.7% to 29.1% by zip code when evaluating hot spots. In general, it was observed that average-risk baby boomers who had the highest percentage (hot spots) of HCV antibody test ordered and the highest percentage (hot spots) of HCV antibody test completed tended to live closer to the healthcare system. Patient level characteristics associated with areas with the highest percentage (hot spots) of HCV antibody test ordered included being female (two-thirds were female), having Medicare insurance (20.1% to 50.0%), having greater than 10+ healthcare visits (15.1% to 41.0%). Similar results were found for hot spot areas with the highest percentage of HCV antibody test. Population-based characteristics associated with the highest (hot spots) HCV antibody test ordered among those who had low poverty levels (4.0% to 32.8%), had low unemployment rates for those age 16+ (1.8% to 12.0%), and had low percentages of people who used public transportation (0.0% to 2.8%), variable percentages of race/ethnicity, and were equally divided by sex. Similar results were found in hot spots for HCV antibody test completion.

Conclusions: We found low HCV screening estimates (< 13%) among studies assessed in our systematic literature review in the U.S. Consequently, intervention efforts (e.g. screening and treatment) targeting baby boomers will be important to improve HCV-related disease outcomes. Additionally, to reduce hepatocellular carcinoma related to chronic HCV infections in the U.S., policies and funding are needed to support HCV screening programs to increase uptake of HCV screening. Targeted HCV screening may be warranted for baby boomer populations who are less likely to have an HCV ordered and completed based on patient and population characteristics by using zip code level data by state. Patient level facilitators to HCV antibody test order and completion include being female, having healthcare insurance (Medicare) for baby boomers, having 10+ healthcare visits while population-based characteristics included low poverty percentages, low unemployment, and low use of public transportation, which may be an indicator of economic stability. Future HCV screening interventions should identify facilitators and barriers to HCV screening using a geospatial lens to address HCV screening disparities in vulnerable populations.

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