Outcomes in anti-NMDAR encephalitis are poorly understood but may be influenced by factors not adequately captured using the modified Rankin Scale (mRS).

This retrospective, observational cohort study examined outcome measures (mRS and clinical assessment scale in autoimmune encephalitis, CASE) in adults with anti-NMDAR-IgG in CSF at hospital discharge and long-term follow-up. Linear and logistic regression modeled outcomes. Mixed models examined predictor effects by time. Subgroups with evaluations for cognitive impairment (CI) (Montreal Cognitive Assessment or Mini-Mental State Examination) >6 months from symptom onset and depression (Patient Health Questionnaire-9) and anxiety (General Anxiety Disorder-7) within 1 year of long-term follow-up were reported. Spearman correlations were examined between mood and final CASE scores.

Thirty-eight patients (76.3% female, median disease onset age=28 years, IQR=22-36) were included. The majority received first- (97.4%) and second-line (68.4%) immunosuppressants at a median of 3.9 weeks (IQR=2.1-9.7).

Median/mean mRS and CASE were 4 (IQR=3-5) and 12.7 (SD=7) at baseline and 2 (IQR=1-3) and 4 (SD=4.1) at long-term follow-up (median=70 weeks, IQR=51-174). Both improved from baseline (p<0.001).

At hospital discharge (median=10 weeks, IQR=6-17), predictors of higher CASE and mRS scores included: dysautonomia, coma/lethargy, seizures/status epilepticus, and intensive care unit admission (p<0.05).

At long-term follow-up, only onset weakness predicted higher mRS scores (OR=5.62, CI 1.02-30.90, p=0.047). Seizures were uncommon (3%). Psychiatric morbidity was the main contributor to final CASE scores (mean=1.3, SD=0.94).

In subgroup analyses, moderate-severe CI (50%), depression (29.5%), and anxiety (41.6%) were frequent. There was a correlation between depression (r=0.65, p<0.01) and anxiety (r=0.79, p<0.01) measures with final CASE memory sub-scores.