Association Between Hospital Volume and Mortality in Status Epilepticus: A National Cohort Study

Complications during and after ICU stay are associated with increased mortality after status epilepticus

BACKGROUND

Status Epilepticus (SE) is a neurological emergency with high mortality rate that often requires admission in Intensive Care Units (ICU). Several factors of worse outcome have been identified in prior studies. The aim of our study was to determine the mortality in ICU and in the ward in patients with SE admitted to an ICU and to identify risk factors of mortality.

METHODS

Retrospective cohort study of patients admitted with SE treated in the ICU of a tertiary medical center between 2015 and 2020. The primary outcome measure was mortality in the ICU (ICU death) or in the ward after ICU discharge (post-ICU death).

RESULTS

252 patients were included, with a mean age of 63 (±16) years and 127 males (50 %). 58 died in the ICU, 27 died in the ward. Overall mortality was associated with a higher burden of comorbidities (OR:1.28, p < 0.001), the use of vasopressors (OR: 5.65, p < 0.001) and a higher burden of ICU complications (OR: 1.32, p = 0.002). Mortality rate was higher in more severe SE episodes (nonconvulsive, acute symptomatic and refractoriness. In-ICU mortality was associated with the use of vasopressors (OR: 7.92, p<0.001) and mechanical ventilation (OR: 3.13, p = 0.031), the length of in-ICU stay (OR: 0.91, p = 0.005) and a higher burden of ICU complications (OR: 1.37, p = 0.001). Compared to post-ICU deaths, ICU deaths also had higher Sequential Organ Failure Assessment (SOFA) score on ICU admission (p<0.001). Post-ICU mortality was associated with a higher burden of comorbidities (OR: 1.34, p<0.001), a higher burden of complications after ICU-discharge (OR: 1.33, p = 0.01), and more often refractory SE episode (OR: 2.63, p = 0.01). Compared to survivors, post-ICU deaths experienced mostly infectious and respiratory complications, after ICU-discharge.

CONCLUSION

Death was more frequent in more severe SE episodes: non convulsive semiology, acute etiology, and refractoriness. In-ICU, post-ICU and all-cause mortality in patients with SE admitted to an ICU are all associated with a higher burden of comorbidities, which are non-modifiable prognostic factors, but also with a higher burden of complications, some of which are preventable, such as respiratory infections.

Understanding the Influence of Hospital Volume on Inpatient Outcomes Following Hospitalization for Status Epilepticus

BACKGROUND

Prior studies show hospital admission volume to be associated with poor outcomes following elective procedures and inpatient medical hospitalizations. However, it is unknown whether hospital volume impacts Inpatient outcomes for status epilepticus (SE) hospitalizations. In this study, we aimed to assess the impact of hospital volume on the outcome of patients with SE and related inpatient medical complications.

METHODS

The 2005 to 2013 National Inpatient Sample database was queried using International Classification of Diseases 9th Edition diagnosis code 345.3 to identify patients undergoing acute hospitalization for SE. The National Inpatient Sample hospital identifier was used as a unique facility identifier to calculate the average volume of patients with SE seen in a year. The study cohort was divided into three groups: low volume (0-7 patients with SE per year), medium volume (8-22 patients with SE per year), and high volume (> 22 patients with SE per year). Multivariate logistic regression analyses were used to assess whether medium or high hospital volume had lower rates of inpatient medical complications compared with low-volume hospitals.

RESULTS

A total of 137,410 patients with SE were included in the analysis. Most patients (n = 50,939; 37%) were treated in a low-volume hospital, 31% (n = 42,724) were treated in a medium-volume facility, and 18% (n = 25,207) were treated in a high-volume hospital. Patients undergoing treatment at medium-volume hospitals (vs. low-volume hospitals) had higher odds of pulmonary complications (odds ratio [OR] 1.18 [95% confidence interval {CI} 1.12-1.25]; p < 0.001), sepsis (OR 1.24 [95% CI 1.08-1.43] p = 0.002), and length of stay (OR 1.13 [95% CI 1.0 -1.19] p < 0.001). High-volume hospitals had significantly higher odds of urinary tract infections (OR 1.21 [95% CI 1.11-1.33] p < 0.001), pulmonary complications (OR 1.19 [95% CI 1.10-1.28], p < 0.001), thrombosis (OR 2.13 [95% CI 1.44-3.14], p < 0.001), and renal complications (OR 1.21 [95% CI 1.07-1.37], p = 0.002). In addition, high-volume hospitals had lower odds of metabolic (OR 0.81 [95% CI 0.72-0.91], p < 0.001), neurological complications (OR 0.80 [95% CI 0.69-0.93], p = 0.004), and disposition to a facility (OR 0.89 [95% CI 0.82-0.96], p < 0.001) compared with lower-volume hospitals.

CONCLUSIONS

Our study demonstrates certain associations between hospital volume and outcomes for SE hospitalizations. Further studies using more granular data about the type, severity, and duration of SE and types of treatment are warranted to better understand how hospital volume may impact care and prognosis of patients.

Factors associated with 30-day readmission for patients hospitalized for seizures

Background

We sought to determine the cumulative incidence of readmissions after a seizure-related hospitalization and identify risk factors and readmission diagnoses.

Methods

We performed a retrospective cohort study of adult patients hospitalized with a primary discharge diagnosis of seizure (International Classification of Diseases, Ninth Edition, Clinical Modification codes 345.xx and 780.3x) using the State Inpatient Databases across 11 states from 2009 to 2012. Hospital and community characteristics were obtained from the American Hospital Association and Robert Wood Johnson Foundation. We performed logistic regressions to explore effects of patient, hospital, and community factors on readmissions within 30 days of discharge.

Results

Of 98,712 patients, 13,929 (14%) were readmitted within 30 days. Reasons for readmission included epilepsy/convulsions (30% of readmitted patients), mood disorders (5%), schizophrenia (4%), and septicemia (4%). The strongest predictors of readmission were diagnoses of CNS tumor (odds ratio [OR] 2.1, 95% confidence interval [CI] 1.9-2.4) or psychosis (OR 1.8, 95% CI 1.7-1.8), urgent index admission (OR 2.0, 95% CI 1.8-2.2), transfer to nonacute facilities (OR 1.7, 95% CI 1.6-1.8), long length of stay (OR 1.7, 95% CI 1.6-1.8), and for-profit hospitals (OR 1.7, 95% CI 1.6-1.8). Our main model's c-statistic was 0.66. Predictors of readmission for status epilepticus included index admission for status epilepticus (OR 3.5, 95% CI 2.6-4.7), low hospital epilepsy volume (OR 0.4, 95% CI 0.3-0.7), and rural hospitals (OR 4.8, 95% CI 2.1-10.9).

Conclusion

Readmission is common after hospitalization for seizures. Prevention strategies should focus on recurrent seizures, the most common readmission diagnosis. Many factors were associated with readmission, although readmissions remain challenging to predict.