A score that predicts 1-year functional status in patients with anti-NMDA receptor encephalitis

Abstract

Objective: To construct a grading score that predicts neurologic function 1 year after diagnosis of anti-NMDA receptor (NMDAR) encephalitis.

Methods: Three hundred eighty-two patients with detailed information and functional status at 1 year were studied. Factors associated with poor status (defined as modified Rankin Scale score ≥3) were identified and incorporated into a multivariate logistic regression model. This model was used to develop a 5-point prediction score, termed the anti-NMDAR Encephalitis One-Year Functional Status (NEOS) score.

Results: Intensive care unit admission (p < 0.001), treatment delay >4 weeks (p = 0.012), lack of clinical improvement within 4 weeks (p < 0.001), movement disorder (p = 0.001), central hypoventilation (p < 0.001), elevated CSF white blood cell count (p < 0.001), elevated CSF protein level (p = 0.027), and abnormal MRI (p = 0.002) were associated with 1-year functional status in univariate analysis. Intensive care unit admission, treatment delay >4 weeks, lack of clinical improvement within 4 weeks, abnormal MRI, and CSF white blood cell count >20 cells/μL were independent predictors for outcome in multivariate regression modeling. These 5 variables were assigned 1 point each to create the NEOS score. NEOS score strongly associated with the probability of poor functional status at 1 year (3% for 0 or 1 point to 69% for 4 or 5 points, p < 0.001).

Conclusions: The NEOS score accurately predicts 1-year functional status in patients with anti-NMDAR encephalitis. This score could help estimate the clinical course following diagnosis and may aid in identifying patients who could benefit from novel therapies.

Figure 1. NEOS score predicts 1-year functional status

(A) Graph shows the probability of good functional status at 1 year vs NEOS score for all patients in the analyzed cohort. Increasing NEOS score is strongly associated with lower probability of good functional status at 1 year (p < 0.001, Cuzick nonparametric test for trend). Error bars represent 95% confidence intervals for each measurement. (B) Distribution of mRS values across NEOS score values. There is a progressive shift toward higher 1-year mRS values with increasing NEOS score. mRS = modified Rankin Scale; NEOS = anti-NMDAR Encephalitis One-Year Functional Status.

Figure 2. Impact of first- and second-line therapies on NEOS score

(A) Distribution of NEOS scores in patients who received only first-line therapies and in patients who received second-line therapies. There is a shift toward higher NEOS scores in patients who received second-line therapies. (B) Relationship between NEOS score and probability of good functional status at 1 year is similar in patients who received only first-line therapies compared to those who received second-line therapies. NEOS = anti-NMDAR Encephalitis One-Year Functional Status.

Figure 3. Distribution of NEOS score and relationship to outcome over time

(A) Distribution of NEOS scores stratified by year of symptom onset. Over time, there is a shift toward lower NEOS score values in patients with more recent symptom onset. (B) Relationship between NEOS score and probability of good functional status at 1 year is similar across different groups. NEOS = anti-NMDAR Encephalitis One-Year Functional Status.