The longitudinal health economic impact of viral encephalitis in the United States.

Introduction. Previous studies of viral encephalitis have focused on acute costs, estimating incidence at 7.3 per 100 000 and total US annual charges at $2 billion in 2010.Aim. We aim to quantify the most updated longitudinal health economic impact of viral encephalitis in the USA from 2008 to 2015.Methodology. Data on patients diagnosed with viral encephalitis were obtained from the Truven Health Analytics MarketScan database. Patients with a primary diagnosis of viral encephalitis, from herpetic viruses and other viral aetiologies (e.g. West Nile fever) were included in the analysis. Data concerning healthcare resource utilization, inpatient mortality, length of stay and accrued healthcare costs were collected for up to 5 years.Results. Among 3985 patients with continuous enrolment for 13 months prior to the encephalitis diagnosis, more non-herpes simplex encephalitis (61.7 %) than herpes simplex encephalitis (HSE; 38.3 %) cases were recorded, with the majority concentrated in the southern USA (29.2 %). One-year inpatient mortality was 6.2 %, which over a 5-year period rose to 8.9 % for HSE and 5.8 % for all other viral encephalitides. HSE resulted in longer cumulative stays in the hospital (11 days vs. 4 days; P=0.0025), and accrued 37 % higher first-year costs, after adjusting for known confounders [P<0.001, cost ratio=1.37, 95 % confidence interval (1.20, 1.57)]. Additionally, HSE was associated with greater 5-year cumulative median charges ($125 338 vs. $82 317, P=0.0015).Conclusion. The health economic impact and long-term morbidity of viral encephalitis in the USA are substantial.

Initial and long-term costs of patients hospitalized with West Nile virus disease.

There are no published data on the economic burden for specific West Nile virus (WNV) clinical syndromes (i.e., fever, meningitis, encephalitis, and acute flaccid paralysis [AFP]). We estimated initial hospital and lost-productivity costs from 80 patients hospitalized with WNV disease in Colorado during 2003; 38 of these patients were followed for 5 years to determine long-term medical and lost-productivity costs. Initial costs were highest for patients with AFP (median $25,117; range $5,385-$283,381) and encephalitis (median $20,105; range $3,965-$324,167). Long-term costs were highest for patients with AFP (median $22,628; range $624-$439,945) and meningitis (median $10,556; range $0-$260,748). Extrapolating from this small cohort to national surveillance data, we estimated the total cumulative costs of reported WNV hospitalized cases from 1999 through 2012 to be $778 million (95% confidence interval $673 million-$1.01 billion). These estimates can be used in assessing the cost-effectiveness of interventions to prevent WNV disease.

Burden of encephalitis-associated hospitalizations in the United States, 1988-1997.

Analysis of the National Hospital Discharge Survey data for 1988-1997 revealed a substantial disease burden associated with encephalitis in the United States: on average, there were nearly 19,000 hospitalizations (7.3 hospitalizations per 100,000 population), 230,000 hospital days, and 1400 deaths annually. For most encephalitis-associated hospitalizations (59.5%), the etiologic agent was unknown or not recorded; the most common etiologic categories among known causes were "viral" (38.2%) and "other infectious" (34.1%). The most common individual diagnoses with known agents were herpetic and toxoplasmic encephalitides (each associated with an annual average of 2100 hospitalizations). Human immunodeficiency virus infection was listed among discharge diagnoses for 15.6% of hospitalizations. Rates of encephalitis-associated hospitalization were highest for children <1 year old and persons > or =65 years old. The etiology of encephalitis was unknown for persons > or =65 years old significantly more often than it was for younger persons. The average cost of an encephalitis-associated hospitalization, as determined by the Healthcare Cost and Utilization Project for 1997, was $28,151, for an annual national cost of hospitalization of $650 million.