Objective:

To determine whether hydrocephalus is independently associated with in-hospital mortality in tuberculous meningitis (TBM) and whether this association is modified by age.

Approach:

• Study Design: A single-center retrospective cohort study of non-HIV TBM patients hospitalized between October 2013 and January 2024.
• Statistical Analysis: Utilized least absolute shrinkage and selection operator regression for variable selection followed by Firth's penalized logistic regression for mortality association estimation.
• Age-Related Analysis: Examined age-related effect modification through categorical and continuous interaction terms, stratified analyses, and restricted cubic splines modeling.

Key Findings:

• In-hospital mortality rate was 11.9% among 1,574 patients.
• Hydrocephalus was independently associated with increased mortality risk across all age groups.
• No statistically significant interaction between hydrocephalus and age was detected.
• Predicted mortality increased with older age in both hydrocephalus groups, particularly in older patients, but the relative effect of hydrocephalus remained consistent across age.

Interpretation:

Hydrocephalus is a strong predictor of in-hospital mortality in TBM, with no statistically significant evidence of age modification in its effect.

Limitations:

• The pediatric subgroup was relatively small, leading to wider confidence intervals, which may affect the reliability of the findings.

Conclusion:

Findings indicate the importance of monitoring hydrocephalus in TBM patients of all ages.