Journal of Biometrics & Biostatistics

ISSN: 2155-6180

Open Access

Current Issue

Volume 11, Issue 3 (2020)

    Research Article Pages: 1 - 7

    Developing and then Confirming a Hypothesis Based on a Chronology of Several Clinical Trials: A Bayesian Application to Pirfenidone Mortality Results

    Zhengning Lin* and Donald A Berry

    DOI: 10.37421/jbmbs.2020.11.441

    Background: Designing a study for independent confirmation of a treatment effect is sometimes not practical due to required large sample size. Post hoc pooling of studies
    including those for learning purposes is subject to selection bias and therefore not scientifically solid. We propose a Bayesian approach which calibrates the role of prior information
    from historical studies for learning and confirming purposes. The method is illustrated in the analysis of mortality data for the pirfenidone NDA.
    Methods: The pirfenidone NDA includes three placebo-controlled studies to demonstrate efficacy for idiopathic pulmonary fibrosis (IPF), a rare and ultimately fatal lung disease with
    no approved treatment in the US at the time of NDA. The results of two earlier conducted studies PIPF-004 and PIPF-006 suggested that pirfenidone might reduce mortality risk.
    We used a Bayesian analysis to synthesize mortality results from the subsequent confirmative Study PIPF-016 and the combination of Studies PIPF-004 and PIPF-006.
    Results: Pirfenidone’s treatment effect on mortality rate reduction for Study PIPF-016 is statistically significant with discounts of historical evidence from PIPF-044 and PIPF-006
    for both all-cause mortality and treatment-emergent IPF-related mortality.
    Conclusions: The Bayesian analysis provides a formal method to calibrate the role of information from historical evidence in the overall interpretation of results from both historical
    and concurrent clinical studies. The increased efficiency of using all available data is especially important in drug development for rare diseases with serious consequences, where
    limited patient source prohibits large trials, and unmet medical needs demand rapid access to treatment options.

    Research Pages: 1 - 10

    Prospectively Estimating the Age of Initiation of E-Cigarettes among U.S. Youth: Findings from the Population Assessment of Tobacco and Health (Path) Study, 2013-2017

    Adriana Pérez1,2*, Meagan Bluestein2, Baojiang Chen1,2, Cheryl L. Perry3 and Melissa B. Harrell2,4

    DOI: 10.37421/jbmbs.2020.11.442

    Context: There is a lack of research that prospectively estimates the age of initiation of electronic cigarette use in U.S. youth. Younger ages of initiation of tobacco product
    use are associated with greater exposure to nicotine, and recently e-cigarette use has been associated with subsequent cigarette initiation. This study sought to estimate
    the distribution of the age of first reporting of e-cigarette use outcomes among youth never e-cigarette users overall, by sex and by race/ethnicity, prospectively.
    Methods: Secondary analysis of the Population Assessment of Tobacco and Health (PATH) youth dataset (ages 12-17) across waves 1 (2013-2014), 2 (2014-2015), 3
    (2015-2016), and 4 (2016-2017) were conducted. Four outcomes are presented, age of first report of: (i) susceptibility to use, (ii) ever, (iii) past 30-day use, and (iv) “fairly
    regular” e-cigarette use. Each outcome was prospectively estimated using participant age when they entered the study and the number of weeks between the last report of
    never use and the first report of each outcome across waves. Weighted survival analyses for interval censoring accounting for the complex survey design were implemented.
    Results: Among youth non-susceptible to e-cigarettes, 50.2% became susceptible to e-cigarette use by age 18. There were no statistically significant differences in the
    age of first report of susceptibility to e-cigarette use by sex or by race/ethnicity in this nationally representative sample of U.S. youth. Among never users, 41.7%, 23.5%
    and 10.3% initiated ever, past 30-day and “fairly regular” e-cigarette use by the age of 18, respectively. Less than 10% initiated ever e-cigarette use between the ages of
    18 and 21. Boys had a higher risk of first reporting ever, past 30-day and “fairly regular” e-cigarette use at earlier ages than girls. Non-Hispanic Blacks and Other racial/
    ethnic groups were less likely than Non-Hispanic Whites to initiate ever e-cigarette use at earlier ages, and there was no difference between Non-Hispanic Whites and
    Hispanics. Hispanic, Non-Hispanic Black and Other racial/ethnic youth were less likely to first report past 30-day use and “fairly regular” e-cigarette use at earlier ages than
    Non-Hispanic White youth.
    Conclusion: This paper provides information on specific ages of the first report of e-cigarette use behaviors by sex and by race/ethnicity that can be used to tailor culturally
    e-cigarette interventions on specific windows of opportunity before youth begin using e-cigarettes or escalating their use.

    Editor Note Pages: 1 - 1

    Editorial : Journal of Biometrics & Biostatistics

    Praneeth Janagani

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