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Meta-Analysis
. 2023 May 4;27(1):170.
doi: 10.1186/s13054-023-04411-y.

Heterogeneity in the definition of delirium in ICUs and association with the intervention effect in randomized controlled trials: a meta-epidemiological study

Lucie Collet  1   2 , Aymeric Lanore #  1   3 , Camille Alaterre #  2 , Jean-Michel Constantin  2 , Guillaume L Martin  1 , Agnès Caille  4 , Arthur James  2 , Agnès Dechartres  5
Affiliations
Meta-Analysis

Heterogeneity in the definition of delirium in ICUs and association with the intervention effect in randomized controlled trials: a meta-epidemiological study

Lucie Collet et al. Crit Care. .

Abstract

Purpose: To evaluate the heterogeneity in the definition of delirium in randomized controlled trials (RCTs) included in meta-analyses of delirium in intensive care units (ICUs) and to explore whether intervention effect depends on the definition used.

Methods: We searched PubMed for meta-analyses including RCTs evaluating prevention or treatment strategies of delirium in ICU. The definition of delirium was collected from RCTs and classified as validated (DSM criteria, CAM-ICU, ICDSC, NEECHAM, DRS-R98) or non-validated (non-validated scales, set of symptoms, physician appreciation or not reported). We conducted a meta-epidemiological analysis to compare intervention effects between trials using or not a validated definition by a two-step method as primary analysis and a multilevel model as secondary analysis. A ratio of odds ratios (ROR) < 1 indicated larger intervention effects in trials using a non-validated definition.

Results: Of 149 RCTs (41 meta-analyses), 109 (73.1%) used a validated definition and 40 (26.8%) did not (including 31 [20.8%] not reporting the definition). The primary analysis of 7 meta-analyses (30 RCTs) found no significant difference in intervention effects between trials using a validated definition and the others (ROR = 0.54, 95% CI 0.27-1.08), whereas the secondary multilevel analysis including 12 meta-analyses (67 RCTs) found significantly larger effects for trials using a non-validated versus a validated definition (ROR = 0.36, 95% CI 0.21-0.62).

Conclusion: The definition of delirium was heterogeneous across RCTs, with one-fifth not reporting how they evaluated delirium. We did not find a significant association with intervention effect in the primary analysis. The secondary analysis including more studies revealed significantly larger intervention effects in trials using a non-validated versus a validated definition.

Keywords: Definition; Delirium; Heterogeneity; Intensive care; Meta-analysis; Meta-epidemiology.

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Conflict of interest statement

The authors declare that they have no conflict of interest.

Figures

Fig. 1
Fig. 1
Definition of delirium in included RCTs (n = 149). Legends: RCT = randomized controlled trial; DSM = diagnostic and statistical manual of mental disorders; CAM-ICU = Confusion Assessment Method for the Intensive Care Unit; ICDSC = Intensive Care Delirium Screening Checklist; DRS-R98 = Delirium Rating Scale Revised-98
Fig. 2
Fig. 2
Primary meta-epidemiological analysis using the two-step method: Comparison of intervention effects between trials using a validated definition of delirium (DSM criteria, CAM-ICU, ICDSC, NEECHAM or DRS-R98) and those using a non-validated definition (non-validated scales, set of symptoms, definition left to the physician appreciation or not reported). Note An ROR < 1 indicates larger intervention effect estimates for RCTs using a non-validated definition than a validated definition. DSM = diagnostic and statistical manual of mental disorders; CAM-ICU = Confusion Assessment Method for the Intensive Care Unit; ICDSC = Intensive Care Delirium Screening Checklist; DRS-R98 = Delirium Rating Scale Revised-98; RCT = randomized controlled trial; ROR = ratio of odds ratios; CI = confidence interval
Fig. 3
Fig. 3
Secondary meta-epidemiological analysis using the multilevel model: Comparison of intervention effects between trials using a validated definition of delirium (DSM criteria, CAM-ICU, ICDSC, NEECHAM or DRS-R98) and those using a non-validated definition (non-validated scales, set of symptoms, definition left to the physician appreciation or not reported), and between trials using the DSM criteria (reference category) and those using the CAM-ICU, a non-validated scale or not reporting the definition used. Note This analysis is based on 12 meta-analyses (67 RCTs). For the first ROR, an ROR < 1 indicates larger intervention effect estimates for RCTs using a non-validated definition than a validated definition. For other RORs, an ROR < 1 indicates larger intervention effects for RCTs using the CAM-ICU or a non-validated scale or a definition not reported as compared with the DSM criteria. DSM = diagnostic and statistical manual of mental disorders; CAM-ICU = Confusion Assessment Method for the Intensive Care Unit; ICDSC = Intensive Care Delirium Screening Checklist; DRS-R98 = Delirium Rating Scale Revised-98; RCT = randomized controlled trial; ROR = ratio of odds ratios; CI = confidence interval
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