Combined Severity Score Better Predicts Mortality in Status Epilepticus

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Combined Severity Score Better Predicts Mortality in Status Epilepticus
Combined Severity Score Better Predicts Mortality in Status Epilepticus

Status epilepticus (SE) affects an estimated 1041 in 100,000 people, with a short-term mortality rate of 7–39%. Identifying mortality predictors could inform clinical decision-making pertaining to SE patients, and a recent retrospective cohort study published in the European Journal of Neurology explored the utility of one particular approach.

While previous research has linked short-term prognostic factors of SE such as older age and acute symptomatic etiology with worse outcomes, findings are inconsistent regarding variables like altered level of consciousness, total SE duration and pre-treatment seizure duration, or time to treatment.

The Status Epilepticus Severity Score (STESS) was previously developed by researchers as a simple tool to assess the prognosis of adults with SE before starting treatment. “The score consists of 4 variables that are available at presentation: history of seizures, age, seizure type, and consciousness impairment,” the authors of the current paper wrote. The STESS has been shown to reliably identify SE patients with an increased likelihood of survival, suggesting that an early aggressive treatment plan may not be routinely justified for such patients due to the associated risks. “However, the STESS has low predictive value for bad outcomes and has a ceiling effect especially in patients older than 65 years without pre-existing epilepsy,” they said.

The researchers of the current study hypothesized that including the modified Rankin Scale (mRS) in the STESS (thereby creating the mSTESS) could improve mortality prediction. They investigated this concept in an analysis of various data from patients with SE aged 16 years and older who were admitted to the Vall d'Hebron University Hospital, Spain, over a period of 3 years. SE “was defined as a condition resulting either from the failure of the mechanisms responsible for seizure termination or from the initiation of mechanisms which lead to abnormally prolonged seizures after 5 min for tonic-clonic SE and 10 min focal SE,” explained the authors.

The primary outcome was mortality status at the time of hospital discharge, and the results showed a total mortality rate of 22.1% among the 136 patients included in the study. Univariate analysis revealed that the factors associated with increased mortality were age, etiology, non-convulsive SE in coma, marked impairment of consciousness, the STESS , and the mRS. The only independent factors of mortality, however, were the STESS (OR 1.863, 95% CI, 1.345– 2.577; P < .001) and the mRS (OR 1.459, 95% CI, 1.004–2.19; P = .047).

The mRS was found to predict mortality at a rate of 65.2% (95% CI, 54.2%–76.2%), and the STESS rate was 74.3% (95% CI, 63.8%–81.8%), while the mSTESS predicted mortality at a rate of 80.1% (95% CI, 70.6%–89.6%). The new scale provides a superior positive predictive value “than the STESS, thereby allowing those patients with a higher risk of mortality to be better identified,” the authors concluded.

Reference

Gonzalez-Cuevas M, Santamarinaa E, Toledo M, et al. A new clinical score for the prognosis of status epilepticus in adults. Eur J Neurol. 2016;0:1–7.

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