Cardiac Arrest and Survival: Is Neurologic Recovery a Predictor of Outcomes?

Complete neurologic recovery after cardiac arrest is associated with improved long-term survival, according to results of a study published in JAMA Network Open.

Researchers conducted a nationwide, observational, register-based cohort study between January 2010 and December 2019 to assess the association between complete neurologic recovery after cardiac arrest and survival. Data were sourced from the Swedish Register for Cardiopulmonary Resuscitation (SRCR), Swedish Cause of Death Register, National Patient Registry, and Statistics Sweden. Adults who survived in-hospital or out-of-hospital cardiac arrest through 30 days and underwent predefined neurologic assessment at hospital discharge using the Cerebral Performance Category (CPC) scale were divided into one of 3 categories:  

• CPC 1: no or minimal neurologic injury;
• CPC 2: moderate neurologic disability, but enough cerebral function to live independently and work in a sheltered environment; or,
• CPC 3 or 4: severe neurologic disability or persistent vegetative state.

The primary outcome was long-term survival. To estimate survival associated with CPC, Cox proportional hazards regression models were used.

Of the 9390 patients (median age, 69; men, 69.7%; shockable rhythm, 65.3%) were included in the study, 7374 (78.5%; median age, 68), 1358 (14.5%; median age, 72), and 658 (7.0%; median age, 69) had CPC 1, 2, or 3 or 4 at discharge, respectively. The in-hospital and out-of-hospital cardiac arrest groups comprised 5582 and 3808 patients, respectively.

A total of 3102 deaths occurred during the study period and the median time from cardiac arrest to death or end of follow-up was 1452 days.

The adjusted survival proportions at 1 year for the CPC 1, 2, and 3 or 4 groups were 92.3%, 88.6%, and 83.4%, respectively. At 5 years, the adjusted survival proportions were 73.8%, 64.7%, and 54.2% for the CPC 1, 2, and 3 or 4 groups, respectively. Adjusted survival proportions at 8 years were 63.1%, 52.6%, and 41.6% for the CPC 1, 2, and 3 or 4 groups, respectively.

Compared with the CPC 1 group, the CPC 2 (adjusted hazard ratio [aHR], 1.57; 95% CI, 1.40-1.75) and 3 or 4 (aHR, 2.46; 95% CI, 2.13-2.85) groups had a greater mortality risk.

When stratified by cardiac arrest type, similar associations were observed in the out-of-hospital (CPC 2: aHR, 1.61 [95% CI, 1.36-1.91]; CPC 3 or 4: aHR, 2.53 [95% CI, 2.03-3.15]) and in-hospital (CPC 2: aHR, 1.51 [95% CI, 1.30-1.77]; CPC 3 or 4: aHR, 2.38 [95% CI, 1.96-2.90]) cardiac arrest groups.

Study limitations include the reduced generalizability of results, potential selection bias and residual confounding, and possibly inaccurate CPC scoring. “[C]omplete neurologic recovery at hospital discharge among 30-day survivors after IHCA [in-hospital cardiac arrest] and OHCA [out-of-hospital cardiac arrest] was associated with better long-term survival compared with moderate or severe neurologic disabilities at the same time point,” the study authors concluded.