Prolonged elevated heart rate and 28-day mortality in acute exacerbations of chronic obstructive pulmonary disease patients insights from the MIMIC-IV database

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) represent a significant global health burden, and severe exacerbations are associated with worse prognoses. We defined prolonged elevated heart rate (PeHR) as a heart rate exceeding 100 beats per minute for at least 11 h within any continuous 12-hour period. However, the relationship between PeHR and outcomes in patients with AECOPD remains unclear. We identified AECOPD patients in the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database and divided them into two groups according to the presence or absence of PeHR. The primary outcome was 28-day mortality. We evaluated the association between PeHR and 28-day mortality using multivariable Cox proportional-hazards models and propensity-score matching. A total of 931 patients with AECOPD were included, 49.6% of whom were male. PeHR occurred in 30.0% of patients. The overall mean age was 72.1 years, and patients with PeHR were younger than those without (71.1 vs. 72.5 years; P < 0.001). Twenty-eight-day mortality was significantly higher in the PeHR group compared with the non-PeHR group (30.3% vs. 15.8%; P < 0.001). In multivariable Cox regression, PeHR was an independent risk factor for 28-day mortality (hazard ratio, 2.16; 95% CI, 1.62-2.87; P < 0.001). After propensity-score matching, the increased mortality in the PeHR group persisted. Prespecified subgroup analyses showed generally consistent effect sizes across all subgroups. PeHR is independently associated with increased 28-day mortality in patients with AECOPD.