Diabetes in resuscitated comatose out-of-hospital cardiac arrest patients - A substudy of the randomized BOX trial.

Background and objectives: This study aimed to assess mortality rates in resuscitated comatose out-of-hospital cardiac arrest patients with and without diabetes randomized to targets of blood pressure, oxygen and duration of fever prevention.

Methods: Diabetic and non-diabetic patients from the BOX trial was compared. The BOX trial was a randomized, controlled, multi-centre study comparing two mean arterial blood pressure targets (63vs77 mm Hg) in a double-blinded intervention and two open labelled targets including a liberal and restrictive oxygenation (9-10vs13-14 kPa) target and two regimes for length of fever-control (36vs72 hours). The primary outcome for this substudy is 365-day survival. Multiple logistic regression models were used to adjust for factors known to be associated with outcome including age, sex, witnessed arrest (y/n) and time to return of spontaneous circulation (min).

Results: A total of 110 (14%) patients had preexisting diabetes. Compared to the non-diabetic group, the patients with diabetes were older (median years (IQR) 67 (59;73)) vs 63 (53;72)) and had more comorbidities.The diabetic patients had an overall increased 365-day all-cause mortality (45 % vs 34 %, p=0.02). The logistic regression model adjusting for age and sex, witnessed arrest (y/n) and place of arrest of arrest gave an estimated adjusted odds ratio of 1.47 (0.93-2.30), p=0.10. No significant interactions were observed among interventions and outcomes related to diabetes status, p ranging from 0.10 to 0.80.

Conclusions: Preexisting diabetes was associated with an increased crude 365-day mortality. No differences in outcome were observed among diabetic OHCA patients depending on the assessed blood pressure targets, oxygen levels and durations of fever control.