Survival and cost-effectiveness of helicopter versus ground emergency medical services: a systematic review and meta-analysis with meta-regression and trial sequential analysis.

OBJECTIVE: To synthesise the available literature comparing outcomes of ground emergency medical services (GEMS) and helicopter emergency medical services (HEMS). METHODS: We conducted a systematic review and meta-analysis, reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Scopus, Web of Science, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched from 1995 to 2024. Studies comparing HEMS with GEMS in emergency conditions were eligible. RESULTS: The search retrieved 1,595 records; 181 studies were assessed in full text, and 77 were included, accounting for a pooled population of 2,618,483 patients. The relative risk (RR) of mortality in HEMS compared with GEMS was 1.13 (95% CI 0.96-1.34). The RR of disability was 1.24 (95% CI 0.99-1.55). The total incremental net benefit was €980,000 per QALY per patient, based on cost-effectiveness studies and a willingness-to-pay threshold of €35 million per QALY per patient. CONCLUSION: Very low-quality evidence, due to high heterogeneity, potential confounding from registry-based enrolment, and possible multiple imputation bias, suggested that HEMS did not improve survival compared with GEMS. High-quality studies are needed to further investigate this question. CLINICAL TRIAL REGISTRATION: PROSPERO: International prospective register of systematic reviews, 2024, CRD42024628317.