{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:21:38Z","timestamp":1760059298217,"version":"build-2065373602"},"reference-count":32,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2025,6,5]],"date-time":"2025-06-05T00:00:00Z","timestamp":1749081600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NIH","award":["R21AI147933","P30-AI-124414"],"award-info":[{"award-number":["R21AI147933","P30-AI-124414"]}]},{"name":"High-Performance Computing Center at the University of Kentucky","award":["R21AI147933","P30-AI-124414"],"award-info":[{"award-number":["R21AI147933","P30-AI-124414"]}]},{"name":"Einstein-Rockefeller-CUNY Center for AIDS Research","award":["R21AI147933","P30-AI-124414"],"award-info":[{"award-number":["R21AI147933","P30-AI-124414"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Algorithms"],"abstract":"<jats:p>We propose a new random change point model that utilizes routinely recorded individual-level HIV viral load data to estimate the timing of antiretroviral therapy (ART) initiation in people living with HIV. The change point distribution is assumed to follow a zero-inflated exponential distribution for the longitudinal data, which is also subject to left-censoring, and the underlying data-generating mechanism is a nonlinear mixed-effects model. We extend the Stochastic EM (StEM) algorithm by combining a Gibbs sampler with a Metropolis\u2013Hastings sampling. We apply the method to real HIV data to infer the timing of ART initiation since diagnosis. Additionally, we conduct simulation studies to assess the performance of our proposed method.<\/jats:p>","DOI":"10.3390\/a18060346","type":"journal-article","created":{"date-parts":[[2025,6,5]],"date-time":"2025-06-05T08:34:32Z","timestamp":1749112472000},"page":"346","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Inferring the Timing of Antiretroviral Therapy by Zero-Inflated Random Change Point Models Using Longitudinal Data Subject to Left-Censoring"],"prefix":"10.3390","volume":"18","author":[{"given":"Hongbin","family":"Zhang","sequence":"first","affiliation":[{"name":"Department of Biostatistics, College of Public Health, University of Kentucky, Lexington, KY 40506, USA"},{"name":"Institute for Implementation Science in Population Health, City University of New York, New York, NY 10027, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"McKaylee","family":"Robertson","sequence":"additional","affiliation":[{"name":"Institute for Implementation Science in Population Health, City University of New York, New York, NY 10027, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sarah L.","family":"Braunstein","sequence":"additional","affiliation":[{"name":"Bureau of Hepatitis, HIV, and Sexually Transmitted Infections, Department of Health and Mental Hygiene, New York, NY 10013, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David B.","family":"Hanna","sequence":"additional","affiliation":[{"name":"Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY 10461, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Uriel R.","family":"Felsen","sequence":"additional","affiliation":[{"name":"Department of Medicine, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY 10461, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Levi","family":"Waldron","sequence":"additional","affiliation":[{"name":"Institute for Implementation Science in Population Health, City University of New York, New York, NY 10027, USA"},{"name":"Department of Epidemiology and Biostatistics, Graduate School of Public Health and Health Policy, City University of New York, New York, NY 10027, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Denis","family":"Nash","sequence":"additional","affiliation":[{"name":"Institute for Implementation Science in Population Health, City University of New York, New York, NY 10027, USA"},{"name":"Department of Epidemiology and Biostatistics, Graduate School of Public Health and Health Policy, City University of New York, New York, NY 10027, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,6,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1682","DOI":"10.1093\/infdis\/jiw438","article-title":"Increase in CD4+ T-Cell Count at the Time of HIV Diagnosis and Antiretroviral Treatment Initiation Among Persons with HIV in New York City","volume":"214","author":"Braunstein","year":"2016","journal-title":"J. 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