Self-reported health status collected within months of in-hospital cardiac arrest was linked to survival patterns observed years later, according to a recent study.
In a nationwide Swedish cohort study, investigators examined whether health-related quality of life (HRQOL) measured 3 to 6 months following in-hospital cardiac arrest (IHCA) or out-of-hospital cardiac arrest (OHCA) was associated with long-term survival, with differing levels of certainty between the two populations. Among 2,000 survivors of IHCA, those reporting the poorest HRQOL had more than twice the risk of mortality during follow-up of up to 7 years compared with patients reporting no problems across quality-of-life domains. Intermediate quality-of-life scores weren't associated with statistically significant differences in survival. Further, categorical quality-of-life groupings weren't significantly associated with mortality among 1,108 survivors of OHCA, although analyses treating quality-of-life measures as continuous variables suggested increasing mortality risk with poorer self-reported health.
The investigators conducted a register-based cohort study linking five national Swedish registries, including the Swedish Register for Cardiopulmonary Resuscitation and the Swedish Cause of Death Register. Adult patients who survived at least 90 days following IHCA or emergency medical services–treated OHCA between January 1, 2014, and December 31, 2019, were eligible if they completed standardized follow-up questionnaires 3 to 6 months after the cardiac arrest. Survival was assessed through June 30, 2021, with follow-up time calculated from the date of HRQOL assessment.
HRQOL was measured using the EuroQoL 5-dimension 5-level tool, which evaluates mobility, self-care, usual activities, pain or discomfort, and anxiety or depression. Responses were summarized using a level sum score ranging from 5 to 25, indicating no problems in any domain to extreme problems in all domains, respectively, as well as a visual analog scale score reflecting overall perceived health. Associations with long-term survival were evaluated using Cox proportional hazards regression models adjusted for age, sex, cardiac arrest characteristics, year and location of cardiac arrest, neurologic status at discharge, socioeconomic factors, and comorbid conditions. Missing covariate data were handled using multiple imputation.
During follow-up, 475 deaths occurred among the survivors of IHCA and 132 among the survivors of OHCA. In the in-hospital cohort, a level sum score of 11 to 25 was associated with a substantially higher risk of death compared with a score of 5, whereas no association was observed for scores of 6 to 10. Continuous modeling demonstrated progressively higher risks of death with worsening level sum scores and lower visual analog scale ratings in both cohorts, although the estimates were less precise among the survivors of OHCA. Depressive symptoms were associated with reduced long-term survival among the survivors of IHCA, whereas anxiety symptoms weren't.
The investigators acknowledged several limitations. HRQOL data were missing for nearly 50% of otherwise eligible survivors of IHCA and more than 60% of survivors of OHCA, raising concerns about selection bias and limited generalizability to patients with more severe impairments. The observational design precluded causal inference, residual confounding couldn't be excluded, and the generic instruments used may not have captured cardiac arrest–specific sequelae. In addition, HRQOL was assessed at a single time point, which may not have reflected changes during longer-term recovery.
“In this cohort study of patients who survived beyond 90 days after IHCA or OHCA, poorer HRQOL reported with [EuroQoL 5-dimension 5-level] scores 3 to 6 months after cardiac arrest was associated with reduced long-term survival in both groups, with greater uncertainty for OHCA estimates. HRQOL assessment may help guide follow-up care,” noted lead study author Emelie Dillenbeck, MD, of the Department of Clinical Science and Education at the Center for Resuscitation Science at the Karolinska Institutet in Sweden, and colleagues.
Disclosures: Co–study author Per Nordberg, MD, PhD, reported receiving grants from the Swedish Heart and Lung Foundation during the conduct of the study and nonfinancial support from the Swedish Cardiopulmonary Resuscitation Registry outside the submitted work. Senior study author Martin Jonsson, PhD, reported being a working group leader in the European Cooperation in Science and Technology Precision Medicine for Cardiac Arrest action. The study authors reported no other conflicts of interest.
Source: JAMA Network Open
