Mid-term (30- to 90-day) neurological changes in out-of-hospital cardiac arrest patients: A nationwide retrospective study (the JAAM-OHCA registry)

Objective
Few studies have focused on mid/long-term neurological changes in out-of- hospital cardiac arrest (OHCA) survivors. Some studies suggest that there is still a slow, small, progressive improvement in cognitive function and quality of life for this population, even in the mid/long term. However, clinical data focused on mid/long-term outcomes for OHCA patients are still lacking. This study aimed to assess mid-term neurological changes in OHCA patients. We summarized patients' improved or worsened neurological changes between 30 and 90 days. Then we identified the relationship between clinical variables and 30- to 90-day neurological improvement.

Methods
A retrospective review of data (Jun 2014 - Dec 2017) from a Japanese nationwide OHCA registry was conducted. Inclusion criteria were OHCA patients ≥18 years old. Exclusion criteria were death within 30 days and missing Cerebral Performance Category (CPC) score at 30 and 90 days. We described the distributions of 30-day and 90-day CPC scores as well as the number and portion of patients whose CPC scores improved and worsened between 30 and 90 days. Additionally, factors affecting improved neurological changes over the time period were examined using multivariable logistic regression.

Results
Of the registry's 34,745 patients, 1868 were analyzed. Favorable neurological outcomes (CPC scores of 1 and 2) were seen in 1020/1868 patients at 90 days. CPC scores at 90 days were: CPC 1: 866 (46%), CPC 2: 154 (8.2%), CPC 3: 224 (12%), and CPC 4: 392 (20%), respectively. A total of 232 patients (CPC 5: 12%) died between 30 and 90 days. In 133 patients (7%), 90-day CPC scores improved compared to their 30-day scores. In 260 patients (14%), 90-day CPC scores worsened compared with their 30-day scores. Application of target temperature management was an independent factor for 30- to 90-day neurological improvement (adjusted odds ratio: 1.69, 95% confidence interval: 1.07–2.68).

Conclusions
In our nationwide registry, 7% of resuscitated patients had improved neurological changes in the 30- to 90-day period; most of the improvements were CPC scores improving from 2 to 1. Target temperature management was an independent factor associated with CPC improvement over the 30- to 90-day period.