# Clinical and Laboratory Predictors of Poor Neurological Outcomes Following Infectious Encephalitis: Systematic Review and Meta‐Analysis

## TL;DR

This study identifies clinical and lab factors that predict poor neurological outcomes after infectious encephalitis, helping guide patient care and prognosis.

## Contribution

First systematic review and meta-analysis on prognostic factors for neurological outcomes after infectious encephalitis.

## Key findings

- Immunocompromised status, status epilepticus, and low Glasgow coma scale predict poor neurological outcomes.
- CSF leucocytosis is linked to better outcomes, while elevated CSF protein is associated with worse outcomes.
- Adjunct steroid therapy shows no significant effect on neurological outcomes.

## Abstract

Infectious encephalitis is a serious global health problem linked to high rates of mortality and morbidity. However, clinical and laboratory factors that impact neurological outcomes following infectious encephalitis remain poorly understood. Accordingly, we undertook a systematic review and meta‐analysis of clinical and laboratory factors influencing neurological outcomes following infectious encephalitis.

We searched MEDLINE and EMBASE from inception to 25th September 2023 for observational studies that reported on neurological outcomes at discharge or at ≥ 6 months. We assessed the prognostic value of a priori selected clinical and laboratory‐based features by estimating pooled risk ratios (RRs) through a random‐effects meta‐analysis. The I
2 statistic was used to assess heterogeneity. This study is registered with PROSPERO (CRD42023485045).

There were several key findings. First, immunocompromised status, status epilepticus, and Glasgow coma scale of < 8 during initial admission were significantly associated with poor neurological outcomes both at discharge and ≥ 6 months after infectious encephalitis onset. Second, CSF leucocytosis [RR: 0.83 95% CI: 0.69–0.98, p = 0.03, n = 5, I
2 = 0%] conferred better neurological outcomes while elevated CSF protein [RR: 1.25 95% CI: 1.07–1.46, p = 0.006, n = 7, I
2 = 0%] was linked to worse neurological outcomes at discharge. Third, there was no significant association between adjunct steroid therapy and neurological outcomes at discharge and ≥ 6 months.

This is the first systematic review and meta‐analysis to investigate prognostic factors linked to neurological outcomes following infectious encephalitis. The results highlight the prognostic value of a range of easily accessible clinical and laboratory parameters.

Clinical and laboratory predictors of long‐term neurological outcomes after infectious encephalitis.