Per-Protocol and Pre-Defined population analysis of the LINC study

Sten Rubertsson; Erik Lindgren; David Smekal; Ollie Östlund; Johan Silfverstolpe; Robert A Lichtveld; Rene Boomars; Wendy Bruins; Björn Ahlstedt; Gunnar Skoog; Robert Kastberg; David Halliwell; Martyn Box; Johan Herlitz; Rolf Karlsten

doi:10.1016/j.resuscitation.2015.07.008

Per-Protocol and Pre-Defined population analysis of the LINC study

Resuscitation. 2015 Nov:96:92-9. doi: 10.1016/j.resuscitation.2015.07.008. Epub 2015 Aug 3.

Authors

Affiliations

¹ Department of Surgical Sciences/Anaesthesiology & Intensive Care, Uppsala University, Uppsala, Sweden. Electronic address: sten.rubertsson@akademiska.se.
² Department of Surgical Sciences/Anaesthesiology & Intensive Care, Uppsala University, Uppsala, Sweden.
³ Uppsala Clinical Research Center, Uppsala University, Uppsala, Sweden.
⁴ Region Skåne Prehospital Center and Skåne University Hospital, Lund, Sweden.
⁵ Regional Ambulance Service Utrecht, Utrecht, Netherlands.
⁶ Västerås Central Hospital, Västerås, Sweden.
⁷ Gävle Hospital, Gävle, Sweden.
⁸ South Western Ambulance Service NHS Foundation Trust Abbey Court, Exeter, United Kingdom.
⁹ The Center of Prehospital Research in Western Sweden and the University College of Borås and Sahlgrenska University Hospital, Sweden.

PMID: 26247144
DOI: 10.1016/j.resuscitation.2015.07.008

Abstract

Objective: To perform two predefined sub-group analyses within the LINC study and evaluate if the results were supportive of the previous reported intention to treat (ITT) analysis.

Methods: Predefined subgroup analyses from the previously published LINC study were performed. The Per-Protocol population (PPP) included the randomized patients included in the ITT-population but excluding those with violated inclusion or exclusion criteria and those that did not get the actual treatment to which the patient was randomized. In the Pre-Defined population (PDP) analyses patients were also excluded if the dispatch time to ambulance arrival at the address exceeded 12 min, there was a non-witnessed cardiac arrest, or if it was not possible to determine whether the arrest was witnessed or not, and those cases where LUCAS was not brought to the scene at the first instance.

Results: After exclusion from the 2589 patients within the ITT-population, the Per-Protocol analysis was performed in 2370 patients and the Pre-Defined analysis within 1133 patients. There was no significant difference in 4-h survival of patients between the mechanical-CPR group and the manual-CPR group in the Per-Protocol population; 279 of 1172 patients (23.8%) versus 281 of 1198 patients (23.5%) (risk difference -0.35%, 95% C.I. -3.1 to 3.8, p=0.85) or in the Pre-Defined population; 176 of 567 patients (31.0%) versus 192 of 566 patients (33.9%) (risk difference -2.88%, 95% C.I. -8.3 to 2.6, p=0.31). There was no difference in any of the second outcome variables analyzed in the Pre-Protocol or Pre-Defined populations.

Conclusions: The results from these predefined sub-group analyses of the LINC study population did not show any difference in 4h survival or in secondary outcome variables between patients treated with mechanical-CPR or manual-CPR. This is consistent with the previously published ITT analysis.

Trial registration: ClinicalTrials.gov NCT00609778.

Keywords: Cardiac arrest; Defibrillation; LUCAS CPR; Mechanical chest compression; Out-of-hospital cardiac arrest; Randomized controlled trial.

Publication types

Multicenter Study
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Aged, 80 and over
Ambulances
Cardiopulmonary Resuscitation / methods*
Electric Countershock / methods*
Emergency Medical Services / methods*
Female
Heart Massage / methods*
Humans
Male
Middle Aged
Out-of-Hospital Cardiac Arrest / therapy*
Population Surveillance / methods*
Treatment Outcome
Young Adult

Associated data

ClinicalTrials.gov/NCT00609778