Body weight and mortality in Takotsubo syndrome: insights from the International Takotsubo (InterTAK) Registry

Aims The obesity paradox has been described in different cardiovascular conditions. Data on the association between obesity and outcomes in patients with Takotsubo syndrome (TTS) are lacking. The aim of this study was to determine the relationship between body weight and mortality in TTS patients. Methods Patients enrolled in the International Takotsubo Registry from January 2011 to July 2021 and with available data on body mass index (BMI) were included in the analysis. Patients were stratified according to BMI (underweight, <18.5 kg/m 2 ; normal weight, 18.5–24.9 kg/m 2 ; overweight, 25.0–29.9 kg/m 2 ; obese, 30.0–34.9 kg/m 2 ; and very obese, ≥35.0 kg/m 2 ). The primary endpoint was mortality at 1 year. Results Of the 2707 patients, 222 (8.2%) were underweight, 1340 (49.5%) of normal weight, 759 (28.0%) overweight, 268 (9.9%) obese and 118 (4.4%) very obese (p=0.02). Rates of mortality at 1 year were 11.3%, 6.9%, 5.5%, 4.9% and 9.3% in underweight, normal weight, overweight, obese and very obese patients (p=0.02). Being overweight or obese was significantly associated with a lower mortality rate at 1 year (HR 0.70, 95% CI 0.51 to 0.96, p=0.03), and this association remained significant after multivariable adjustments (adjusted HR 0.67, 95% CI 0.46 to 0.97, p=0.03). Conclusion A U-shaped mortality curve across BMI categories was observed in TTS patients, with the highest mortality rates observed in underweight and the lowest rates observed in obese patients. These observations provide the first evidence for the existence of the obesity paradox in TTS. Trial registration number NCT01947621 .