Advanced age and neurological recovery in elderly patients with out-of-hospital cardiac arrest treated with targeted temperature management: a nationwide population‑based registry study 2016-2020.

The likelihood of neurological recovery after out-of-hospital cardiac arrest (OHCA) may be influenced by advanced age. This study aims to evaluate the impact of advanced age on neurological recovery in elderly OHCA survivors treated with targeted temperature management (TTM). This retrospective observational study, using a nationwide population-based OHCA registry, was conducted from January 2016 to December 2020. Non-traumatic elderly (≥ 65 years) comatose OHCA survivors treated with TTM were categorized according to age (65-69, 70-74, 75-79, and ≥ 80 years). Among 23,336 admitted OHCA patients, 3,398 were treated with TTM. Excluding 2,033 non-elderly patients, 1,365 were analyzed. Among the four groups, the rate of good neurological outcomes decreased by advanced age (24.2%, 16.1%, 11.4%, and 5.9%, respectively), which was also observed after subgroup analysis based on the initial shockable (40.6%, 31.5%, 28.6%, and 14.9%, respectively) and non-shockable rhythm (10.6%, 7.2%, 4.1%, and 3.4%, respectively). Multivariate analysis showed the adjusted odds ratio (aOR) for good neurological outcome decreased as age increased (65-69: reference, 70-74: aOR 0.70, 75-79: aOR 0.49, and ≥ 80 years: aOR 0.25). The optimal age cutoffs for good outcomes in elderly OHCA survivors with shockable and non-shockable rhythm were 77 and 72 years, respectively. The neurologic recovery rate in OHCA survivors treated with TTM gradually decreased with increasing age. However, even patients aged ≥ 80 years with shockable rhythm had a good neurologic outcome of 14.9% compared with patients aged 65-69 years with non-shockable rhythm (10.6%).