Pharmacologic Modulation of Circadian Rhythms for Delirium Prevention: An Age‐Stratified Systematic Review and Meta‐Analysis.

Background: Disturbances in sleep–wake homeostasis (Process S) and circadian rhythm (Process C) are common precipitants of delirium, especially among older hospitalized adults. We conducted a systematic review and meta‐analysis to test whether four sleep‐modulation agents—melatonin, ramelteon, suvor...

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Published in:Journal of the American Geriatrics Society Vol. 74; no. 5; pp. 1439 - 1450
Main Authors: de Oliveira, Helen Michaela, Gallo Ruelas, Mariano, Parker, Tariq, Diaz, Camilo André Viana, Oliveira de Paula, Guilherme, Zamora, Fernanda Valeriano, Fruett da Costa, Pablo Ramon
Format: Article
Published: Wiley-Blackwell May2026
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Online Access:View this record in EBSCOhost
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      dt: May2026
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      pub: Wiley-Blackwell
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        194163393
        10.1111/jgs.70305
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      tig:
        atl: Pharmacologic Modulation of Circadian Rhythms for Delirium Prevention: An Age‐Stratified Systematic Review and Meta‐Analysis.
      aug:
        au:
          de Oliveira, Helen Michaela
          Gallo Ruelas, Mariano
          Parker, Tariq
          Diaz, Camilo André Viana
          Oliveira de Paula, Guilherme
          Zamora, Fernanda Valeriano
          Fruett da Costa, Pablo Ramon
        affil:
          Department of Medicine, Federal University of Mato Grosso, Sinop Mato Grosso,, Brazil
          Instituto de Investigación Nutricional (IIN), Lima, Peru
          Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston Massachusetts,, USA
          Department of Medicine, Federal University of Triângulo Mineiro, Uberaba Minas Gerais,, Brazil
          Department of Medicine, Federal University of Minas Gerais, Belo Horizonte Minas Gerais,, Brazil
          Department of Functional Neurosurgery, Sinedor Clinic, Sinop Mato Grosso,, Brazil
      su:
        Age distribution
        Old age
        Medical information storage & retrieval systems
        Sedatives
        Melatonin
        Hospital patients
        Meta-analysis
        Relative medical risk
        Descriptive statistics
        Systematic reviews
        MEDLINE
        Delirium
        Circadian rhythms
        Online information services
        Confidence intervals
        Data analysis software
        Regression analysis
        Publication bias
      sug:
        subj:
          Age distribution
          Old age
          Pharmaceutical and medicine manufacturing
          Medical information storage & retrieval systems
          Sedatives
          Melatonin
          Hospital patients
          Meta-analysis
          Relative medical risk
          Descriptive statistics
          Systematic reviews
          MEDLINE
          Delirium
          Circadian rhythms
          Online information services
          Confidence intervals
          Data analysis software
          Regression analysis
          Publication bias
      keyword:
        delirium
        lemborexant
        melatonin
        ramelteon
        suvorexant
        delirium
        lemborexant
        melatonin
        ramelteon
        suvorexant
      ab: Background: Disturbances in sleep–wake homeostasis (Process S) and circadian rhythm (Process C) are common precipitants of delirium, especially among older hospitalized adults. We conducted a systematic review and meta‐analysis to test whether four sleep‐modulation agents—melatonin, ramelteon, suvorexant, and lemborexant—lower delirium incidence or shorten its duration in hospitalized patients, with stratified analyses by drug class, age, and surgical status. Methods: We systematically searched PubMed, Embase, and CENTRAL through March 2025. We included randomized controlled trials (RCTs) and observational studies assessing delirium prevention with melatonin, ramelteon, suvorexant, and lemborexant in hospitalized adults (≥ 18 years), compared to placebo or standard care. Data synthesis was performed separately for RCTs and observational studies using random‐effects models. Meta‐regression was used to explore effect modifiers. Risk of bias was assessed using RoB2/ROBINS‐I tools. Certainty of evidence was graded using the GRADE assessment. Results: Thirty‐seven studies (27 RCTs, 10 observational) comprising 7845 patients were included. Among RCTs, melatonin (RR 0.94; 95% CI 0.72–1.22) and ramelteon (RR 0.63; 95% CI 0.39–1.03) showed no significant effect on delirium incidence, whereas orexin receptor antagonists were associated with a lower risk (RR 0.55; 95% CI 0.35–0.87). Evidence for a class difference was inconsistent across analytic approaches: a subgroup heterogeneity test suggested differential effects (interaction‐p = 0.09), but the meta‐regression found no between‐class difference (p = 0.14). No other specific test for subgroup differences was statistically significant in RCTs. Meta‐regression confirmed patient setting as a significant modifier in observational studies, but not in RCTs. Conclusion: Sleep–wake pharmacotherapies may reduce incident delirium in hospitalized adults. In randomized trials, melatonin and ramelteon did not significantly reduce delirium incidence, whereas dual orexin receptor antagonists showed a possible benefit, but the meta‐regression did not demonstrate a reliable between‐class difference, and the evidence remains limited. Adequately powered randomized trials across inpatient settings are needed to clarify any true differences and define clinical relevance. Summary: Key points ○In randomized trials of hospitalized adults, melatonin and ramelteon did not show a clear reduction in new‐onset delirium, whereas dual orexin receptor antagonists (suvorexant/lemborexant) were associated with fewer delirium cases. However, in prespecified statistical comparisons across drug classes, we did not find convincing evidence that any class is definitively superior. Accordingly, the apparent benefit of orexin antagonists should be considered hypothesis‐generating, given the very low certainty of the evidence.○No age subgroup or inpatient setting consistently modified effects across randomized evidence; setting‐specific signals in observational studies were not corroborated by RCTs and should be considered hypothesis‐generating.○Across > 3400 exposed patients, adverse events were mild and infrequent, with no signal for oversedation, respiratory compromise, or QT prolongation.Why does this paper matter? ○By integrating randomized and observational evidence, this review offers a balanced appraisal of sleep–wake pharmacotherapies for delirium prevention in older inpatients, clarifying both potential benefits and key evidence gaps. We distinguish mechanistic classes (circadian alignment vs. attenuation of orexin‐mediated wake drive) and explicitly compare analytic approaches: while a subgroup test suggested a class signal favoring orexin receptor antagonists, our prespecified random‐effects meta‐regression did not confirm between‐class differences. We therefore prioritize the meta‐regression and treat any apparent class contrast as exploratory, very‐low‐certainty evidence. These insights refine expectations for current practice and define priorities for adequately powered, class‐specific RCTs with standardized dosing/timing and instrument‐specified delirium outcomes.
      pubtype: Academic Journal
      doctype: Article
      src: R
    language: English
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