Impact of the COVID-19 pandemic on the incidence and mortality of Takotsubo syndrome in Sweden, a report from the SWEDEHEART registry

Introduction Takotsubo syndrome (TTS) is often triggered by intense emotional or physical stress, with symptoms closely resembling those of acute myocardial infarction and heart failure. The COVID-19 pandemic caused unprecedented psychological, social, and economic stress, with TTS incidence and mortality either increasing or remaining stable. Previous studies have relied on single- or multicenter data, lacking the scope to provide national-level insights. This study aimed to fill the gap by investigating the incidence and outcomes of TTS across Sweden during two distinct periods: the pre-pandemic period (January 2015 to March 2020) and the pandemic period (April 2020 to December 2022). Methods Using the nationwide Swedish Coronary Angiography and Angioplasty Registry, we assessed the incidence rate (IR) for all patients with TTS referred for coronary angiography in Sweden. We calculated incidence rate ratios (IRRs) both before and during the pandemic using quasi-Poisson regression, adjusted for age and sex. We evaluated 30-day and 1-year mortality using multivariable Cox proportional hazards regression, accounting for clustering within hospitals. Results We identified 3,180 patients hospitalized with TTS during the study period: 69% (2,189) pre-pandemic and 31% (991) during the pandemic. The incidence of TTS was 10% lower during the pandemic compared to the pre-pandemic period (IRR 0.90, 95% CI 0.84–0.97, P = 0.008). The cohort’s crude all-cause mortality rate was 2.73% at 30 days and 6.10% at 1 year, with no significant difference at 30 days (adjusted HR 1.12, 95% CI 0.69–1.78, P = 0.642) or one year (adjusted HR 1.05, 95% CI 0.75–1.46, P = 0.780). Compared with studies in other countries where incidence increased or remained unchanged, COVID-19 incidence was similar across the matching periods. Conclusions This nationwide observational study found a lower incidence of TTS during the pandemic compared to the pre-pandemic period, while mortality rates remained unchanged. The reduced incidence of TTS in Sweden may reflect the country’s comparatively milder pandemic control measures and more robust social security infrastructure relative to other nations. Clinical trial number Not applicable.