Dexamethasone in adults with viral meningitis: an observational cohort study

Objectives

To investigate whether there is a dose-dependent association between empiric dexamethasone and outcome in viral meningitis.

Methods

Observational cohort study of adults hospitalized for viral meningitis, both with and without a microbiologically confirmed diagnosis, in Denmark between 2015 and 2020. Dose-dependent associations between dexamethasone (one dose = 10 mg) and an unfavourable outcome (Glasgow Outcome Scale score 1–4) at 30 days after discharge were assessed using weighted logistic regression. Entropy balancing was used to compute weights.

Results

Of 1025 included patients, 658 (64%) did not receive dexamethasone, 115 (11%) received 1–2 doses, 131 (13%) received 3–4 doses, and 121 (12%) received ≥5 doses. Among patients treated with dexamethasone, the median number of doses was higher for those without an identified pathogen than for those with a microbiologically confirmed viral aetiology (5 [interquartile range (IQR) 3–8] vs. 3 [IQR 2–5]; p < 0.001). Using no doses of dexamethasone as a reference, the weighted OR for an unfavourable outcome were 0.55 (95% CI, 0.29–1.07) for 1–2 doses, 1.13 (95% CI, 0.67–1.89) for 3–4 doses, and 1.43 (95% CI, 0.77–2.64) for ≥5 doses. In the subgroup of enteroviral meningitis, the weighted OR was 3.08 (95% CI, 1.36–6.94) for ≥5 doses, but decreased to 2.35 (95% CI, 0.65–8.40) when the reference group was restricted to patients treated with antibiotics for suspected bacterial meningitis.

Discussion

This study showed no dose-dependent association between dexamethasone and an unfavourable outcome in patients with viral meningitis. In enteroviral meningitis, ≥5 doses were associated with an increased risk of an unfavourable outcome. However, sensitivity analysis indicated that the association was affected by unmeasured or residual confounding by severity.