Critical Care (May 2023)

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

  • Lucie Collet,
  • Aymeric Lanore,
  • Camille Alaterre,
  • Jean-Michel Constantin,
  • Guillaume L. Martin,
  • Agnès Caille,
  • Arthur James,
  • Agnès Dechartres

DOI
https://doi.org/10.1186/s13054-023-04411-y
Journal volume & issue
Vol. 27, no. 1
pp. 1 – 13

Abstract

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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.

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