Nallakkandi Rajeevan, PhD
Senior Research Scientist of Biomedical Informatics and Data ScienceDownloadHi-Res Photo
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Associate Director for Bioinformatics, Yale Center for Medical Informatics
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Appointments
Additional Titles
Associate Director for Bioinformatics, Yale Center for Medical Informatics
Contact Info
Appointments
Additional Titles
Associate Director for Bioinformatics, Yale Center for Medical Informatics
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About
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Senior Research Scientist of Biomedical Informatics and Data Science
Associate Director for Bioinformatics, Yale Center for Medical Informatics
Biography
Dr. Rajeevan's research focuses on applying his deep knowledge in theoretical computer science, algorithm development, statistical estimation theory, and biostatistics to problems in genomics, bioinformatics, nuclear medicine and functional brain imaging. He received his B.E., M.S., and Ph.D. from Indian Institute of Science, Bangalore, India and did his post-doctoral fellowship in Nuclear Medicine from University of Massachusetts Medical Center, Worcester, MA.
Appointments
Biomedical Informatics & Data Science
Senior Research ScientistPrimary
Other Departments & Organizations
Education & Training
- Post-doctoral fellow
- University of Massachusetts Medical Center (1993)
- PhD
- Indian Institute of Science (1992)
- MS
- Indian Institute of Science, Electrical Engineering (1986)
- BE
- Indian Institute of Science, Electronics and Communications (1979)
Research
Overview
Medical Subject Headings (MeSH)
Information Science
ORCID
0000-0002-2045-0872
Research at a Glance
Yale Co-Authors
Frequent collaborators of Nallakkandi Rajeevan's published research.
Publications Timeline
A big-picture view of Nallakkandi Rajeevan's research output by year.
Mihaela Aslan, PhD
Hongyu Zhao, PhD
Joel Gelernter, MD
Maolin Qiu, PhD
Daniel F. Levey, PhD
Erol Fikrig, MD
70Publications
3,890Citations
Publications
Featured Publications
Effectiveness of Nirmatrelvir-Ritonavir Against the Development of Post-COVID-19 Conditions Among U.S. Veterans : A Target Trial Emulation.
Ioannou G, Berry K, Rajeevan N, Li Y, Mutalik P, Yan L, Bui D, Cunningham F, Hynes D, Rowneki M, Bohnert A, Boyko E, Iwashyna T, Maciejewski M, Osborne T, Viglianti E, Aslan M, Huang G, Bajema K. Effectiveness of Nirmatrelvir-Ritonavir Against the Development of Post-COVID-19 Conditions Among U.S. Veterans : A Target Trial Emulation. Annals Of Internal Medicine 2023, 176: 1486-1497. PMID: 37903369, PMCID: PMC10620954, DOI: 10.7326/m23-1394.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsAcute COVID-19Veterans Health AdministrationUntreated comparatorsThromboembolic eventsCOVID-19Severe COVID-19Target trial emulationSARS-CoV-2Post COVID-19 conditionIndex dateVenous thromboembolismBaseline characteristicsCumulative incidencePulmonary embolismAcute infectionMedian ageOral antiviralsTrial emulationVHA careOutpatient treatmentInternational ClassificationHealth AdministrationU.S. veteransVeterans AffairsOrgan systems
2024
Development of a prediction model for 30-day COVID-19 hospitalization and death in a national cohort of Veterans Health Administration patients–March 2022—April 2023
Bui D, Bajema K, Huang Y, Yan L, Li Y, Rajeevan N, Berry K, Rowneki M, Argraves S, Hynes D, Huang G, Aslan M, Ioannou G. Development of a prediction model for 30-day COVID-19 hospitalization and death in a national cohort of Veterans Health Administration patients–March 2022—April 2023. PLOS ONE 2024, 19: e0307235. PMID: 39365775, PMCID: PMC11451987, DOI: 10.1371/journal.pone.0307235.Peer-Reviewed Original ResearchMeSH Keywords and ConceptsConceptsVeterans Health AdministrationCOVID-19 hospitalizationArea under the receiver operating characteristic curveComprehensive electronic health recordNational cohortElectronic health recordsAll-cause mortalityNational cohort of patientsFull modelHealth recordsHealth AdministrationReceipt of COVID-19 vaccineMortality riskEpidemiology of COVID-19COVID-19High-risk patientsBrier scoreCohort of patientsAnti-SARS-CoV-2 treatmentCOVID-19 vaccineReceiver operating characteristic curveCalibration interceptHospitalAntiviral treatmentAvailability of effective vaccinesIdentifying Veterans Who Benefit From Nirmatrelvir-Ritonavir: A Target Trial Emulation
Yan L, Bui D, Li Y, Rajeevan N, Rowneki M, Berry K, Argraves S, Huang Y, Hynes D, Cunningham F, Huang G, Aslan M, Ioannou G, Bajema K. Identifying Veterans Who Benefit From Nirmatrelvir-Ritonavir: A Target Trial Emulation. Clinical Infectious Diseases 2024, 79: 643-651. PMID: 38864601, DOI: 10.1093/cid/ciae202.Peer-Reviewed Original ResearchCitationsAltmetricConceptsRisk quartileVeterans Health AdministrationLowest risk quartileHighest risk quartileTarget trial emulationRisk prediction modelUntreated veteransRisk of deathOlder veteransYounger veteransHealth AdministrationTrial emulationMeasure incidenceNirmatrelvir-ritonavirVeteransHospitalUntreated participantsCOVID-19QuartileRiskSevere coronavirus disease 2019ParticipantsPersonsCoronavirus disease 2019Severe COVID-19Regional variation in financial hardship among US veterans during the COVID-19 pandemic
Hauschildt K, Bui D, Govier D, Eaton T, Viglianti E, Ettman C, McCready H, Smith V, O’Hare A, Osborne T, Boyko E, Ioannou G, Maciejewski M, Bohnert A, Hynes D, Iwashyna T, Chai W, Bowling B, Maciejewski M, Womer J, Iwashyna T, Anderson S, Bernstein T, Cabrales A, Hauschildt K, Admon A, Byrd K, Cano J, Curtis J, DelMonico E, Horowitz D, Kamphius L, Korpela P, Kumbier K, Langa K, Prescott H, Rouse M, Saini S, Seelye S, Sussman J, Wawrin N, Monahan M, Bohnert A, Viglianti E, Akgun K, Aslan M, Cheung K, Li Y, Mutalik P, Rajeevan N, Yan L, Anderson L, Berkowitz T, Bogdan J, Bosworth H, Boucher N, Cummin G, Dennis P, Floyd B, Hastings S, Kaufman B, Meyer C, Miles A, Naylor J, Shepherd-Banigan M, Smith V, Smith B, Woods C, Dobalian A, Goetz M, Ikuta K, Ong M, Shaukat A, Backus L, Ferguson J, Osborne T, Shahoumian T, Veigulis Z, Zulman D, Bajema K, Bui D, Chen J, Govier D, Helfand M, Hickok A, Hough C, McCready H, Moss A, Newell S, Niederhausen M, Nugent S, Saha S, Slatore C, Takata Y, Teo A, Tuepker A, Vranas K, Winchell K, Hynes D, Boyko E, Au D, Baraff A, Berry Wyatt K, Borgerding J, Burwick N, Crothers K, Davis M, Doll J, Dominitz J, Eastment M, Fan V, Fox A, Hawkins E, Hebert P, Hu E, Korpak A, Morelli D, Peterson A, Reddy A, Shah J, Showalter W, Smith N, Suri P, Thomas E, Turner A, Vig E, Wicks K, Wong E, Wysham K, Ioannou G, O'Hare A, Jones B, Jones M, Knight S. Regional variation in financial hardship among US veterans during the COVID-19 pandemic. Health Affairs Scholar 2024, 2: qxae075. PMID: 38938272, PMCID: PMC11210296, DOI: 10.1093/haschl/qxae075.Peer-Reviewed Original ResearchCitationsAltmetricCorrelates of suicidal behaviors and genetic risk among United States veterans with schizophrenia or bipolar I disorder
Bigdeli T, Barr P, Rajeevan N, Graham D, Li Y, Meyers J, Gorman B, Peterson R, Sayward F, Radhakrishnan K, Natarajan S, Nielsen D, Wilkinson A, Malhotra A, Zhao H, Brophy M, Shi Y, O’Leary T, Gleason T, Przygodzki R, Pyarajan S, Muralidhar S, Gaziano J, Huang G, Concato J, Siever L, DeLisi L, Kimbrel N, Beckham J, Swann A, Kosten T, Fanous A, Aslan M, Harvey P. Correlates of suicidal behaviors and genetic risk among United States veterans with schizophrenia or bipolar I disorder. Molecular Psychiatry 2024, 29: 2399-2407. PMID: 38491344, DOI: 10.1038/s41380-024-02472-1.Peer-Reviewed Original ResearchCitationsAltmetricConceptsBipolar I disorderSuicidal behaviorElectronic health recordsPolygenic scoresVeterans Health AdministrationSelf-reported SBColumbia-Suicide Severity Rating ScaleBipolar I disorder patientsCorrelates of suicidal behaviorClasses of psychotropic medicationsSelf-injurious behaviorHealth recordsSeverity Rating ScaleDiagnosed mental illnessAssociated with clinical variablesElectronic health record codesEHR domainDepressive disorderC-SSRSLifetime diagnosisSubstance-relatedPsychotropic medicationsSuicidal ideationExternalizing behaviorsSuicide attemptsSelf-Reported Everyday Functioning After COVID-19 Infection
Iwashyna T, Smith V, Seelye S, Bohnert A, Boyko E, Hynes D, Ioannou G, Maciejewski M, O’Hare A, Viglianti E, Berkowitz T, Pura J, Womer J, Kamphuis L, Monahan M, Bowling C, Admon A, Akgun K, Anderson S, Aslan M, Au D, Backus L, Bajema K, Baraff A, Batten L, Berkowitz T, Bernstein T, Berry Wyatt K, Bogdan J, Bosworth H, Boucher N, Burwick N, Cabrales A, Cano J, Chai W, Chen J, Cheung K, Crothers K, Curtis J, Davis M, Del Monico E, Dobalian A, Doll J, Dominitz J, Eastment M, Fan V, Ferguson J, Floyd B, Fox A, Goetz M, Govier D, Green P, Hastings S, Hauschildt K, Hawkins E, Hebert P, Helfand M, Hickok A, Horowitz D, Hough C, Hu E, Ikuta K, Jones B, Jones M, Kamphuis L, Kaufman B, Knight S, Korpak A, Korpela P, Kumbier K, Langa K, Laundry R, Lavin S, Li Y, Linquist J, McCready H, Michel M, Miles A, Milne J, Monahan M, Morelli D, Mutalik P, Naylor J, Neiderhausen M, Newell S, Nugent S, Ong M, Osborne T, Peterson M, Peterson A, Prescott H, Rajeevan N, Reddy A, Rouse M, Rowneki M, Saha S, Saini S, Shah J, Shahoumian T, Shaukat A, Shepherd-Banigan M, Showalter W, Slatore C, Smith N, Smith B, Suri P, Sussman J, Takata Y, Teo A, Thomas E, Thomas L, Tuepker A, Veigulis Z, Vig E, Vranas K, Wang X, Wicks K, Winchell K, Wong E, Woods C, Wysham K, Yan L, Zulman D. Self-Reported Everyday Functioning After COVID-19 Infection. JAMA Network Open 2024, 7: e240869. PMID: 38427352, PMCID: PMC10907923, DOI: 10.1001/jamanetworkopen.2024.0869.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsEveryday functioningActivities of daily livingSelf-reported everyday functioningCOVID-19 infectionImpact of COVID-19 infectionDaily livingVeterans AffairsCOVID-19 cohortDocumented COVID-19Instrumental activities of daily livingMatched pairs of participantsHealth-related quality of lifePairs of participantsCohort studyProportion of veteransControl cohortLife-space mobilityStudy of veteransCohort study of veteransUS Veterans AffairsHealth-related qualityDocumented COVID-19 infectionSelf-reportTarget trial emulationQuality of lifeChanges in Outpatient Health Care Use After COVID-19 Infection Among Veterans
Hebert P, Kumbier K, Smith V, Hynes D, Govier D, Wong E, Kaufman B, Shepherd-Banigan M, Rowneki M, Bohnert A, Ioannou G, Boyko E, Iwashyna T, O’Hare A, Bowling C, Viglianti E, Maciejewski M, Admon A, Akgun K, Anderson L, Anderson S, Aslan M, Au D, Backus L, Bajema K, Baraff A, Batten L, Berkowitz T, Bernstein T, Berry Wyatt K, Bogdan J, Borgerding J, Bosworth H, Boucher N, Burwick N, Byrd K, Cabrales A, Cano J, Chai W, Chen J, Cheung K, Crothers K, Cummin G, Curtis J, Davis M, Del Monico E, Dennis P, Dobalian A, Doll J, Dominitz J, Eastment M, Fan V, Ferguson J, Floyd B, Fox A, Goetz M, Green P, Hastings S, Hauschildt K, Hawkins E, Helfand M, Hickok A, Horowitz D, Hough C, Hu E, Ikuta K, Jones B, Jones M, Kamphius L, Knight S, Korpak A, Korpela P, Langa K, Laundry R, Lavin S, Li Y, Lindquist J, McCready H, Meyer C, Michel M, Miles A, Milne J, Monahan M, Morelli D, Mutalik P, Naylor J, Niederhausen M, Newell S, Nugent S, Ong M, Osborne T, Peterson M, Peterson A, Prescott H, Pura J, Rajeevan N, Reddy A, Rouse M, Saha S, Saini S, Seelye S, Shah J, Shahoumian T, Shaukat A, Showalter W, Slatore C, Smith B, Smith N, Streja E, Suri P, Sussman J, Takata Y, Teo A, Thomas E, Thomas L, Tuepker A, Turner A, Veigulis Z, Vig E, Vranas K, Wang X, Wicks K, Winchell K, Womer J, Woods C, Wysham K, Yan L, Zulman D. Changes in Outpatient Health Care Use After COVID-19 Infection Among Veterans. JAMA Network Open 2024, 7: e2355387. PMID: 38334995, PMCID: PMC10858406, DOI: 10.1001/jamanetworkopen.2023.55387.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsOutpatient health care useHealth care useCare useOutpatient useOutpatient visitsPrimary care visitsCounts of outpatient visitsPrimary care patientsOutpatient care utilizationCategories of careVeterans Affairs Corporate Data WarehouseCorporate Data WarehouseIncreased outpatient visitsNegative binomial regression modelsBinomial regression modelsCare visitsCare utilizationPopulation surveillance studyRetrospective cohort studyCare patientsUninfected veteransCOVID-19 infectionMain OutcomesPeri-infection periodCohort study
2023
Metformin prescription for U.S. veterans with prediabetes, 2010–2019
Gulanski B, Goulet J, Radhakrishnan K, Ko J, Li Y, Rajeevan N, Lee K, Heberer K, Lynch J, Streja E, Mutalik P, Cheung K, Concato J, Shih M, Lee J, Aslan M. Metformin prescription for U.S. veterans with prediabetes, 2010–2019. Journal Of Investigative Medicine 2023, 72: 139-150. PMID: 37668313, DOI: 10.1177/10815589231201141.Peer-Reviewed Original ResearchMeSH Keywords and ConceptsConceptsBody mass indexVeterans Health AdministrationIncident prediabetesHigh riskHealth AdministrationRetrospective observational cohort studyType 2 diabetes mellitusUse of metforminObservational cohort studyProportion of veteransMetformin prescribingGestational diabetesCohort studyMetformin prescriptionDiabetes mellitusDiabetes preventionMass indexCardiovascular diseaseMultivariable modelPrediabetesSubset of individualsMetforminU.S. veteransHealthcare systemVeteransLate Mortality After COVID-19 Infection Among US Veterans vs Risk-Matched Comparators
Iwashyna T, Seelye S, Berkowitz T, Pura J, Bohnert A, Bowling C, Boyko E, Hynes D, Ioannou G, Maciejewski M, O’Hare A, Viglianti E, Womer J, Prescott H, Smith V, Admon A, Akgun K, Anderson S, Aslan M, Au D, Backus L, Bajema K, Baraff A, Batten L, Berkowitz T, Bernstein T, Berry Wyatt K, Bogdan J, Bosworth H, Boucher N, Burwick N, Cabrales A, Cano J, Chai W, Chen J, Cheung K, Crothers K, Curtis J, Davis M, Del Monico E, Dobalian A, Doll J, Dominitz J, Eastment M, Fan V, Ferguson J, Floyd B, Fox A, Goetz M, Govier D, Green P, Hastings S, Hauschildt K, Hawkins E, Hebert P, Helfand M, Hickok A, Horowitz D, Hough C, Hu E, Ikuta K, Jones B, Jones M, Kamphuis L, Kaufman B, Knight S, Korpak A, Korpela P, Kumbier K, Langa K, Laundry R, Lavin S, Li Y, Linquist J, McCready H, Michel M, Miles A, Milne J, Monahan M, Morelli D, Mutalik P, Naylor J, Neiderhausen M, Newell S, Nugent S, Ong M, Osborne T, Peterson M, Peterson A, Rajeevan N, Reddy A, Rouse M, Rowneki M, Saha S, Saini S, Shah J, Shahoumian T, Shaukat A, Shepherd-Banigan M, Showalter W, Slatore C, Smith N, Smith B, Suri P, Sussman J, Takata Y, Teo A, Thomas E, Thomas L, Tuepker A, Veigulis Z, Vig E, Vranas K, Wang X, Wicks K, Winchell K, Wong E, Woods C, Wysham K, Yan L, Zulman D. Late Mortality After COVID-19 Infection Among US Veterans vs Risk-Matched Comparators. JAMA Internal Medicine 2023, 183: 1111-1119. PMID: 37603339, PMCID: PMC10442778, DOI: 10.1001/jamainternmed.2023.3587.Peer-Reviewed Original ResearchCitationsAltmetricConceptsCOVID-19 infectionAdjusted hazard ratioRetrospective cohort studyUninfected comparatorsLate mortalityCohort studyHazard ratioMortality riskCOVID-19Acute COVID-19Excess mortality riskUnadjusted mortality ratesVeterans Affairs hospitalCOVID-19 persistHealth record dataCause mortalityCox regressionUS veteransExcess mortalityDay 180Mortality rateUninfected individualsPrimary analysisDay 91Excess deathsAnti–SARS-CoV-2 Pharmacotherapies Among Nonhospitalized US Veterans, January 2022 to January 2023
Yan L, Streja E, Li Y, Rajeevan N, Rowneki M, Berry K, Hynes D, Cunningham F, Huang G, Aslan M, Ioannou G, Bajema K. Anti–SARS-CoV-2 Pharmacotherapies Among Nonhospitalized US Veterans, January 2022 to January 2023. JAMA Network Open 2023, 6: e2331249. PMID: 37651140, PMCID: PMC10472184, DOI: 10.1001/jamanetworkopen.2023.31249.Peer-Reviewed Original ResearchCitationsAltmetricMeSH Keywords and ConceptsConceptsCOVID-19 pharmacotherapyVeterans Health AdministrationVeterans Integrated Service NetworkSARS-CoV-2Higher Charlson Comorbidity Index scoresCharlson Comorbidity Index scoreNon-Hispanic veteransComorbidity Index scoreProportion of patientsSymptomatic COVID-19Multivariable logistic regressionCOVID-19 vaccinationCohort studyMedicare databaseVHA careUS veteransMAIN OUTCOMEMedical conditionsHispanic veteransPharmacotherapyHealth AdministrationIndex scoreCommunity careNonhospitalized personsWhite veterans
Academic Achievements & Community Involvement
honor Life Senior Member
International AwardInstitute of Electrical and Electronics Engineers (IEEE), Inc., New YorkDetails10/26/2021United Stateshonor Lifetime Service Award
International AwardIndo-American Society of Nuclear MedicineDetails06/01/2010United States
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