Background: Inflammatory processes can trigger acute coronary syndromes (ACS) which may increase core body temperature (BT), a widely available low-cost marker of systemic inflammation. Herein, we aimed to delineate baseline characteristics of ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation ACS (NSTE-ACS) patients stratified by initial BT and to assess its predictive utility towards major adverse cardiovascular events (MACE) after the index ACS.

Methods: From 2012 until 2017, a total of 1044 ACS patients, 517 with STEMI and 527 with NSTE-ACS, were prospectively recruited at the University Hospital Zurich. BT was measured by digital tympanic thermometer along with high-sensitivity C-reactive protein (hs-CRP) and cardiac troponin-T (hs-cTnT) levels prior to coronary angiography. Patients were stratified according to initial BT and uni- and multivariable regression models were fit to assess associations of BT with future MACE risk.

Results: Among patients with STEMI, BT was not predictive of 1-year MACE, but a U-shaped relationship between BT and MACE risk was noted in those with NSTE-ACS (p = .029), translating into a 2.4-fold (HR, 2.44, 95% CI, 1.16-5.16) increased 1-year MACE risk in those with BT >36.8°C (reference: 36.6-36.8°C). Results remained robust in multivariable-adjusted analyses accounting for sex, age, diabetes, renal function and hs-cTnT. However, when introducing hs-CRP, the BT-MACE association did not prevail.

Conclusions: In prospectively recruited patients with ACS, initial BT shows a U-shaped relationship with 1-year MACE risk among those with NSTE-ACS, but not in those with STEMI. BT is a broadly available low-cost marker to identify ACS patients with high inflammatory burden, at high risk for recurrent ischaemic events, and thus potentially suitable for an anti-inflammatory intervention.

Registration: ClinicalTrials.gov Identifier: NCT01000701.