Abstracts

Rationale: Apnea and Cardiac Arrhythmias have both been implicated as possible mechanisms that contribute to Sudden unexpected death in epilepsy (SUDEP). Post-convulsion apnea is one of the biomarkers for unexpected deaths. Studies also showed that seizures can present with cardiac arrhythmias and ictal asystole which can contribute to sudden unexpected death. Sudden unexpected death in epilepsy (SUDEP) has an estimated incidence rate of 1.16 cases per 1000 patients with epilepsy, which is the second most common cause of potential life-years lost after the stroke. Patients with intractable epilepsy (IrE) have a higher incidence of SUDEP. Aim of this study was to identify the prevalence, trend, and mortality in patients with apnea, arrhythmia, and both-together amongst epilepsy hospitalizations and to identify the effect modification due to intractable epilepsy on death. Methods: We performed a retrospective cross-sectional analysis of the Nationwide Inpatient Sample (NIS) (years 2003-2014) for pediatric and adult epilepsy hospitalizations to determine the mortality with the secondary diagnosis of apnea and arrhythmia using ICD-9-CM codes. We performed weighted analyses using Chi-Square test and Cochran-Armitage trend test. Subgroup analysis using multivariable survey logistic regression interaction modeling based on epilepsy severity (intractable and non-intractable) had been performed to evaluate the effect modification. Among those groups, odds of mortality with secondary diagnosis of apnea, arrhythmia, and both-together had been identified. Results: Out of the total 2,682,987 epilepsy hospitalizations, 207,264 (7.70%) patients presented with IrE. Amongst epilepsy hospitalizations, overall prevalence of apnea, arrhythmia and both together were 73,908 (2.75%), 239,179 (8.91%), and 13,222 (0.49%), respectively. Among IrE-subgroup, prevalence of apnea, arrhythmia, and both together were 7501 (3.62%), 6924 (3.34%) and 755 (0.36%). We noticed an incremental prevalence trend of apnea (Overall: 1.38% in 2003 to 3.87% in 2014; IrE: 1.92% in 2003 to 4.72% in 2014), arrhythmia (Overall: 7.40% in 2003 to 10.43% in 2014; IrE: 2.03% in 2003 to 4.72% in 2014) and both together (Overall: 0.15% in 2003 to 0.83 in 2014; IrE: 0.14% in 2003 to 0.54% in 2014). (p-Trend <0.0001) In univariate analysis, prevalence of mortality was highest among patients with arrhythmia in compare to other. (arrhythmia:3.10% vs. apnea:0.48% vs both:2.91% vs. none:0.46%). (p<0.0001). In multivariable regression analysis, independent odds of mortality associated with IrE, apnea, arrhythmia, and both together were 1.17, 0.84, 3.29, and 3.24 respectively. (p significant) Epilepsy patients with apnea, arrhythmia, and both together, odds of death increased by 128% (OR: 0.79 --> 2.07), , 518% (OR: 3.21 --> 8.39), and 863% (OR: 3.01 --> 11.64) respectively, when hospitalization complicated with IrE. (p<0.0001) Conclusions: The data demonstrates the prevalence of Apnea & Arrhythmia in epilepsy patients and also the effect of these two variables on mortality. This study has also looked at the data for patients with intractable epilepsy. The data shows the increase in mortality in epilepsy patients with arrhythmias and those with a combination of arrhythmias and apnea. This study indicates that attention to these variables would be important in identifying patients at risk for SUDEP. Funding: No funding