Ethnicity and survival from out-of-hospital cardiac arrest: a New Zealand registry study.
Howie G, Conaglen K, Dicker B.
Objective: To determine the relationships between survival from all-cause out-of-hospital cardiac arrest (OHCA) and ethnicity in New Zealand.
Methods: A retrospective observational study was conducted using data compliant with the Utstein guidelines from the St John Ambulance New Zealand OHCA Registry for adult patients who were treated for an OHCA between 1 October 2013 and 30 September 2015.
Primary outcomes measured were: Return of spontaneous circulation (ROSC) sustained to handover at hospital, and survival to thirty-days, for New Zealanders of these ethnicities: European, indigenous Māori, Pasifika (Pacific Islanders), and Other. Standard Utstein elements were also probed, such as: locality of arrest, whether or not the OHCA was witnessed, CPR and defibrillation prior to ambulance arrival, initial rhythm, aetiology.
Results: Ethnic origins of 3214 OHCA patients were: 59.9% European, 24.2% indigenous Māori, 9% Pasifika (Pacific Islanders), 6.9% Other. ROSC sustained to hospital handover was: 32.3% Europeans, 26.9% Māori, 28.5% Pasifika, 32.9% Other (p<0.03, Pearson Chi-Square.) Survival to thirty-days was: 18.1% European, 10.5% Māori, 13.5% Pasifika, 12.7% Other (p<0.001, Pearson Chi-Square). Significant differences between ethnicities were seen in: location, aetiology, witnessed/non-witnessed, CPR prior to ambulance arrival, initial rhythm (all p<0.05, Pearson Chi-Square).
Time to ambulance arrival was no different across ethnicities (median time, 8-9 minutes, p=0.59, Pearson Chi-Square); defibrillation by public before ambulance arrival was similar for all groups.
Conclusions: Utstein-favourable factors such as initial shockable rhythm, witnessed arrest and bystander-CPR may contribute to these differences in survival from OHCA between ethnicities. Proposed additional factors include differences in: socioeconomic status, cardiovascular risk factors, and rural/urban localities.