Research Summary
Dr. Varadhan is a well-known expert in several areas of biostatistics. He is an expert in the area of patient-centered outcomes research (PCOR), where he focuses on developing statistical methods that inform evidence-based individualized medicine. He has a particular interest in Bayesian methods for exploring heterogeneity of treatment effect (HTE). He has also developed algorithms and software for solving high-dimensional optimization problems arising in statistical modeling. Dr. Varadhan developed a class of algorithms called SQUAREM (squared extrapolation methods) that accelerate the convergence of expectation-maximization (EM) and minorization-maximization (MM) algorithms. He has written several R packages for solving various types of problems in statistical modeling and in optimization, including turboEM, for which he received the 2012 John M. Chambers award for best statistical software. Dr. Varadhan has also made significant contributions to the etiology of frailty in older adults.
Selected Publications
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Ambinder A, Jain T, Tsai HL, Horowitz MM, Jones RJ, Varadhan R. HLA-matching with PTCy: a reanalysis of a CIBMTR dataset with propensity score matching and donor age. Blood Adv. 2022 Jul 26;6(14):4335-4346. doi: 10.1182/bloodadvances.2022007741. PMID: 35613462; PMCID: PMC9327541
Schoenborn NL, Blackford AL, Joshu CE, Boyd CM, Varadhan R. Life expectancy estimates based on comorbidities and frailty to inform preventive care. J Am Geriatr Soc. 2022 Jan;70(1):99-109. doi: 10.1111/jgs.17468. Epub 2021 Sep 18. PMID: 34536287; PMCID: PMC8742754
Lanzkron S, Little J, Wang H, Field JJ, Shows JR, Haywood C Jr, Saheed M, Proudford M, Robertson D, Kincaid A, Burgess L, Green C, Seufert R, Brooks J, Piehet A, Griffin B, Arnold N, Frymark S, Wallace M, Abu Al Hamayel N, Huang CY, Segal JB, Varadhan R. Treatment of Acute Pain in Adults With Sickle Cell Disease in an Infusion Center Versus the Emergency Department : A Multicenter Prospective Cohort Study. Ann Intern Med. 2021 Sep;174(9):1207-1213. doi: 10.7326/M20-7171. Epub 2021 Jul 6. Erratum in: Ann Intern Med. 2021 Aug 3; PMID: 34224261
Henderson NC, Louis TA, Rosner GL, Varadhan R. Individualized treatment effects with censored data via fully nonparametric Bayesian accelerated failure time models. Biostatistics. 2020 Jan 1;21(1):50-68. doi: 10.1093/biostatistics/kxy028. PMID: 30052809; PMCID: PMC8972560
Henderson NC, Varadhan R. Damped Anderson acceleration with restarts and monotonicity control for accelerating EM and EM-like algorithms. J Comput Graph Stat. 2019;28(4):834-846
