Prognostic significance of different body temperature trajectories and fever in patients with ST-segment elevation myocardial infarction

Abstract Introduction Despite advances in reperfusion therapy, survivors of ST-segment elevation myocardial infarction (STEMI) remain at high risk of major adverse cardiovascular and cerebrovascular events (MACCE). Although post-infarction inflammatory responses may influence outcomes, the role of body temperature (BT) patterns during hospitalization, particularly the timing of fever onset, in prognosis remains to be fully elucidated. Existing studies yield conflicting results, with limited evidence on whether early versus delayed fever episodes differentially predict long-term prognosis. Purpose This study aimed to investigate the associations between BT trajectories, temporal pattern of fever and 1-year MACCE in STEMI survivors. Methods A total of 2376 STEMI patients discharged from 2012 to 2022 were consecutively enrolled. Patients with a continuous axillary BT record of less than 4 days and active infection/antibiotic use were excluded. According to the three BT trajectories identified by the group-based trajectory model, the onset phase of fever (≥ 37.3°C) was divided into no fever, early fever (within 3 days), and late fever (from day 4 to 7). Multivariable adjusted Cox proportional hazards models were used to estimate the association between the first-day BT, peak first-week BT, onset phases of fever and the risk of MACCE. We also examined the relationships between primary percutaneous coronary intervention (PPCI), baseline inflammation and different onset phases of fever. Results The mean age of the patients was 61.2 ± 12.3 years, and 1049 (44.1%) underwent PPCI. Of these, 407 (17.1%) patients developed fever in the 1st week of admission, and 123 (5.2%) had late fever. At the 1-year follow-up, 202 (8.5%) patients experienced MACCE. After adjustment for traditional cardiovascular risk factors and PPCI, the risk of MACCE in patients with late fever was 76.4% higher than that in patients without fever (HR 1.764, 95% CI 1.081-2.879; p = 0.023), while early fever was not associated with prognosis (p = 0.226). First-day BT (HR 1.127 per 1 °C, 95% CI 0.696-1.824) and peak first-week BT (HR 1.170 per 1 °C, 95% CI 0.840-1.632) showed no significant association with the outcome. Between patients who received PPCI and those who did not, there was no significant difference in the rate of late fever. Baseline levels of the inflammatory marker interleukin-6 were significantly different between patients with various onset phases of fever. Conclusions Delayed post-infarction fever onset independently predicts 1-year MACCE. Temperature monitoring beyond the acute phase may enhance risk stratification, potentially guiding targeted anti-inflammatory strategies. These findings emphasize the temporal dynamics of post-infarction fever as a novel prognostic marker.