Health economic impact of early versus delayed treatment of herpes simplex virus encephalitis in the UK
Authors: Defres Sylviane , Navvuga Patricia , Hardwick Hayley , Easton Ava , Michael Benedict D , Kneen Rachel , Griffiths Michael J , Medina-Lara Antonieta , Solomon Tom 
Published: February 2024

Objective

Thanks to the introduction of recent national guidelines for treating herpes simplex virus (HSV) encephalitis health outcomes have improved. This paper evaluates the costs and the health-related quality of life implications of these guidelines.

Design and setting

A sub-analysis of data from a prospective, multi-centre, observational cohort ENCEPH-UK study conducted across 29 hospitals in the UK from 2012 to 2015.

Study participants

Data for patients aged ≥16 years with a confirmed HSV encephalitis diagnosis admitted for treatment with aciclovir were collected at discharge, 3 and 12 months.

Primary and secondary outcome measures

Patient health outcomes were measured by the Glasgow outcome score (GOS), modified ranking score (mRS), and the EuroQoL; health care costs were estimated per patient at discharge from hospital and at 12 months follow-up. In addition, Quality Adjusted Life years (QALYs) were calculated from the EQ-5D utility scores. Cost-utility analysis was performed using the NHS and Social Scare perspective.

Results

A total of 49 patients were included, 35 treated within 48 hours “early” (median [IQR] 8.25 [3.7-20.5]) and 14 treated after 48 hours (median [IQR] 93.9 [66.7 - 100.1]). At discharge, 30 (86%) in the early treatment group had a good mRS outcome score (0–3) compared to 4 (29%) in the delayed group. EQ-5D-3L utility value at discharge was significantly higher for early treatment (0.609 vs 0.221, p<0.000). After adjusting for age and symptom duration at admission, early treatment incurred a lower average cost at discharge, £23,086 (95% CI: £15,186 to £30,987) vs £42,405 (95% CI: £25,457 to £59,354) [p<0.04]. A -£20,218 (95% CI: -£52,173 to £11,783) cost difference was observed at 12-month follow-up post discharge.

Conclusions

This study suggests that early treatment may be associated with better health outcomes and reduced patient healthcare costs, with a potential for savings to the NHS with faster treatment.

Article Summary

Strengths and limitations of this study

- Admissions to acute hospitals with suspected encephalitis, using predetermined inclusion criteria were recruited across 29 hospitals in the UK within a 3-year period, giving the largest cohort of prospectively recruited HSV encephalitis cases in the UK to date.

- Precise definitions to characterise those individuals with proven HSV encephalitis were applied thus ensuring accurate diagnoses.

- Individuals were followed up systematically for 12 months after discharge for clinical, and quality of life data providing the first study to assess the effect of treatment delays on health care resources, costs and health related quality of life.

- The analysis is limited by its relatively small sample size due to it being a rare disease, and the case record forms although thorough may not capture all health care costs incurred. This is particularly so for primary care and community care contact outside of the study hospitals.