A risk score for unfavorable outcome in adults with bacterial meningitis

Objective: To derive and validate a bedside risk score for adverse outcome in adults with bacterial meningitis. Methods: We derived a score for the risk for an unfavorable outcome (Glasgow Outcome Scale score 1-4) by performing logistic regression analyses of data from a prospective cohort study (Dutch Meningitis Cohort; N = 696). A key set of independent prognostic variables was selected from 22 potential predictors. A nomogram based on these key variables was constructed to facilitate use in clinical practice. To validate this nomogram, we used data from our randomized controlled trial on adjunctive dexamethasone therapy in adults with bacterial meningitis (European Dexamethasone Study; N = 301). Results: Unfavorable outcome occurred in 237 of 696 episodes (34%) in the Dutch Meningitis Cohort; 143 patients (21%) died. In the analysis, 6 of 22 variables that are routinely available within I hour after admission were robust enough for inclusion in the final risk score: age, heart rate, Glasgow Coma Scale score, cranial nerve palsies, a cerebrospinal fluid leukocyte count less than 1,000 cells/mm(3), and gram-positive cocci in cerebrospinal fluid Gram's stain. The concordance index for the risk score was 0.84 (95% confidence interval, 0.80-0.87) in the original cohort and 0.81 (95% confidence interval, 0.74-0.87) in the external validation cohort (European Dexamethasone Study). Interpretation: This bedside risk score can be used to identify patients with a high risk for unfavorable outcome in adults with bacterial meningitis within I hour after the initial presentation.