Risk score predictive of mortality in status epilepticus according to a national database

Nonconvulsive status epilepticus in neurocritical care: A critical reappraisal of outcome prediction scores

OBJECTIVE

Nonconvulsive status epilepticus (NCSE) is a frequent condition in the neurocritical care unit (NCCU) patient population, with high morbidity and mortality. We aimed to assess the validity of available outcome prediction scores for prognostication in an NCCU patient population in relation to their admission reason (NCSE vs. non-NCSE related).

METHODS

All 196 consecutive patients diagnosed with NCSE during the NCCU stay between January 2010 and December 2020 were included. Demographics, Simplified Acute Physiology Score II (SAPS II), NCSE characteristics, and in-hospital and 3-month outcome were extracted from the electronic charts. Status Epilepticus Severity Score (STESS), Epidemiology-Based Mortality Score in Status Epilepticus (EMSE), and encephalitis, NCSE, diazepam resistance, imaging features, and tracheal intubation score (END-IT) were evaluated as previously described. Univariable and multivariable analysis and comparison of sensitivity/specificity/positive and negative predictive values/accuracy were performed.

RESULTS

A total of 30.1% died during the hospital stay, and 63.5% of survivors did not achieve favorable outcome at 3 months after onset of NCSE. Patients admitted primarily due to NCSE had longer NCSE duration and were more likely to be intubated at diagnosis. The receiver operating characteristic (ROC) for SAPS II, EMSE, and STESS when predicting mortality was between .683 and .762. The ROC for SAPS II, EMSE, STESS, and END-IT when predicting 3-month outcome was between .649 and .710. The accuracy in predicting mortality/outcome was low, when considering both proposed cutoffs and optimized cutoffs (estimated using the Youden Index) as well as when adjusting for admission reason.

SIGNIFICANCE

The scores EMSE, STESS, and END-IT perform poorly when predicting outcome of patients with NCSE in an NCCU environment. They should be interpreted cautiously and only in conjunction with other clinical data in this particular patient group.

Clinical scores and clusters for prediction of outcomes in status epilepticus

Status epilepticus (SE) is a life-threatening condition and may have long-term negative sequelae. Short- and long-term outcomes encompass mortality, deterioration of functional status compared to baseline, refractoriness to treatment, recurrence of SE, and development of epilepsy, cognitive impairment, and behavioral disturbances. So far, the greatest amount of evidence is available for the prediction of short-term mortality. Conversely, the knowledge regarding long-term consequences among SE survivors is still scarce and several issues have not yet been resolved. The heterogeneity of SE renders the prognostication of outcomes challenging. Although aetiology is the main determinant of the outcome, different prognostic predictors have been identified. In this regard, data on group effects need to be integrated into prognostic scores to allow individual risk stratification. Importantly, many of the present scores are not designed to enable repetition to follow patient evolution. A new paradigm for the assessment of SE outcomes should consider variables that become available and/or can be retested during the course of SE. Neuroimaging findings, serum biomarkers, treatment characteristics, complications during SE, peri-ictal and postictal characteristics after SE cessation look as promising determinants of outcome and are suitable for inclusion in future models to enhance the quality and increase the reliability of prediction. This paper was presented at the 8th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures held in September 2022.

Severity scores for status epilepticus in the ICU: systemic illness also matters

BACKGROUND

Current prognostic scores for status epilepticus (SE) may not be adequate for patients in ICU who usually have more severe systemic conditions or more refractory episodes of SE. We aimed to compare the prognostic performance of two SE scores, Status Epilepticus Severity Score (STESS) and Epidemiology-Based Mortality Score in Status Epilepticus (EMSE) score, with four systemic severity scores, Acute Physiology and Chronic Health Evaluation 2 (APACHE-2), Simplified Acute Physiology Score 2 (SAPS-2), Sequential Organ Failure Assessment (SOFA) score, and Inflammation, Nutrition, Consciousness, Neurologic function and Systemic condition (INCNS) score in critically ill patients with SE.

METHODS

This retrospective observational study of a prospectively identified SE cohort was conducted in the ICU at a tertiary-care center. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and associations with outcomes of STESS, EMSE, INCNS, APACHE-2, SAPS-2, and SOFA score for the prediction of in-hospital mortality and no return to baseline condition were assessed.

RESULTS

Between January 2015 and December 2020, 166 patients with SE in ICU were included in the study. In predicting in-hospital death, APACHE-2 (0.72), SAPS-2 (0.73), and SOFA score (0.71) had higher AUCs than STESS (0.58) and EMSE (0.69). In predicting no return to baseline condition, the AUC of APACHE-2 (0.75) was the highest, and the AUC of INCNS (0.55) was the lowest. When the specificity approached 90%, the sensitivity values of these scores were not quite acceptable (< 40%). Neither SE scores nor systemic severity scores had desirable prognostic power. In the multivariate logistic regression analyses, the best combinations of scores always included at least one or more systemic severity scores.

CONCLUSIONS

STESS and EMSE were insufficient in outcome prediction for SE patients in ICU, and EMSE was marginally better than STESS. Systemic illness matters in ICU patients with SE, and SE scores should be modified to achieve better accuracy in this severely ill population. This study mostly refers to severely ill patients in the ICU.

Prognostic scores in status epilepticus: A systematic review and meta-analysis

The performance of prognostic scores of status epilepticus (SE) has been reported in very heterogeneous cohorts. We aimed to provide a summary of the available evidence on their respective performance. PubMed and EMBASE were searched for relevant articles. Studies were reviewed for eligibility for meta-analysis of the area under the receiver-operating characteristic curve (AUC) and for meta-analysis of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) in predicting in-hospital mortality with scores in which at least two external evaluations had been published. This study was registered with PROSPERO (international prospective register of systematic reviews) (CRD42022325766). Study quality was assessed using Prediction model Risk Of Bias ASsessment Tool (PROBAST). In the meta-analysis of AUC, 21 studies were pooled for STESS (Status Epilepticus Severity Score), five for EMSE-EAC (Epidemiology-based Mortality Score in Status Epilepticus - Etiology, Age, level of Consciousness), five for EMSE-EACE (EMSE - Etiology, Age, level of Consciousness, EEG), and two for ENDIT (Encephalitis, nonconvulsive status epilepticus, Diazepam resistance, Imaging abnormalities, Tracheal intubation). The pooled AUC of STESS, EMSE-EAC, EMSE-EACE, and ENDIT was 0.74 (95% CI: 0.71-0.78), 0.68 (95% CI 0.63-0.72), 0.77 (95% CI: 0.72-0.81), and 0.78 (95% CI: 0.70-0.87), respectively. The pooled sensitivity of STESS-3, STESS-4, EMSE-EACE-64, and ENDIT-4 was 0.83 (95% CI: 0.80-0.86), 0.60 (95% CI: 0.55-0.65), 0.76 (95% CI: 0.67-0.83), and 0.70 (95% CI: 0.55-0.82), respectively. Their pooled specificity was 0.50 (95% CI: 0.48-0.52), 0.74 (95% CI: 0.72-0.76), 0.63 (95% CI: 0.59-0.67), and 0.65 (95% CI: 0.61-0.70), respectively. Their pooled PPV was 0.27 (95% CI: 0.24-0.30), 0.35 (95% CI: 0.29-0.41), 0.33 (95% CI: 0.24-0.43), and 0.20 (95% CI: 0.13-0.27). Their pooled NPV was 0.94 (95% CI: 0.93-0.96), 0.90 (95% CI: 0.89-0.92), 0.89 (95% CI: 0.80-0.98), and 0.95 (95% CI: 0.92-0.98). Variations in performance were observed in patients' subgroups, such as critically ill patients and refractory cases. Investigated scores only have acceptable AUC, sensitivity, and specificity for predicting in-hospital mortality, with the EMSE-EAC having a lower discriminative power. STESS-3 has the highest sensitivity, and STESS-4 the highest specificity, but neither combines acceptable sensitivity and specificity. All these scores had high NPV but very low PPV. Caution should be exercised in their clinical use. Further studies are required to develop more accurate scores.

Prediction of in-hospital mortality in status epilepticus: Evaluation of four scoring tools in younger and older adult patients

OBJECTIVE

The goal of this study was to evaluate the predictive capacity of four scoring tools: the Status Epilepticus Severity Score (STESS), the Encephalitis-NCSE-Diazepam resistance-Image abnormalities-Tracheal intubation (END-IT) score, and two variable combinations of the Epidemiology-based Mortality Score in Status Epilepticus (EMSE) in younger and older adult patients with status epilepticus (SE).

METHODS

We present a retrospective hospital-based analysis with a focus on adult patients with SE at three tertiary care hospitals in the Zhejiang province of China. Data were collected from January 2013 to December 2018. The patients were divided into two groups: younger adult patients (18-64 years old) and older adult patients (≥65 years old). Clinical outcomes (dead or alive) were assessed at hospital discharge. The four scoring tools were used to predict in-hospital mortality in both younger and older adult patients.

RESULTS

The mortality rate in older adult patients (25.4%) was higher than in younger adult patients (12.9%). Compared with the elderly, the younger adult patients had a higher proportion of encephalitis, while acute cerebrovascular disease and Charlson Complications Index (CCI) were lower. For the younger adult patients, END-IT had the largest area under the curve (AUC) of 0.843 (95% CI, 0.772-0.899), which was higher than the EMSE-EAL value of 0.687 (95% CI, 0.603-0.763, p < 0.05) and EMSE-EAC of 0.646 (95% CI, 0.561-0.725, p < 0.05). For the older adult patients, EMSE-EAL had the largest AUC of 0.843 (95% CI, 0.738-0.919), which was significantly higher than STESS with an AUC of 0.676 (95% CI, 0.554-0.782, p < 0.05). Moreover, the AUC of EMSE-EAL in the elderly was larger than in younger adult patients. The cutoffs in younger adult patients were STESS ≥ 4 (sensitivity 0.444, specificity 0.951), END-IT ≥ 3 (sensitivity 0.833, specificity 0.672), EMSE-EAL ≥ 31 (sensitivity 0.778, specificity 0.566), and EMSE-EAC ≥ 33 (sensitivity 0.833, specificity 0.492). However, the cutoffs in older adult patients were STESS ≥ 5 (sensitivity 0.500, specificity 0.925), END-IT ≥ 2 (sensitivity 0.944, specificity 0.547), EMSE-EAL ≥ 30 (sensitivity 0.944, specificity 0.623), and EMSE-EAC ≥ 31 (sensitivity 0.944, specificity 0.415).

CONCLUSION

Our results indicated that the STESS, END-IT, EMSE-EAC, and EMSE-EAL scores have excellent capacity to predict in-hospital mortality in both younger and older adult patients with SE. Our study supports the use of END-IT in patients under 65 years of age and suggests that EMSE-EAL is the most suitable scoring tool for patients over 65.