Subcarinal angle and biomarkers associated with mortality in ICU COPD patients

This retrospective cohort study analyzed 108 patients with chronic obstructive pulmonary disease (COPD) admitted to the intensive care unit (ICU). The intervention or exposure was subcarinal angle (SCA) values measured on posterior–anterior chest X-rays (PA-CXRs), with comparisons made between survivor and non-survivor groups. The primary outcome was mortality, and secondary outcomes included congestive heart failure, creatinine levels, C-reactive protein (CRP) levels, albumin levels, Acute Physiology and Chronic Health Evaluation II (APACHE-II) scores, and age.

Main results showed that congestive heart failure was associated with mortality (p = 0.011). Higher creatinine levels (p = 0.034), elevated CRP levels (p = 0.01), hypoalbuminemia (p = 0.018), narrower SCA values (p = 0.025), and higher APACHE-II scores (p = 0.001) were also associated with mortality. Effect sizes and absolute numbers were not reported. Safety and tolerability data were not provided in the input.

Key limitations include the observational design, which precludes causal inferences, and the lack of reported effect sizes or absolute numbers. The sample size of 108 is relatively small, and follow-up duration was not specified. Funding or conflicts of interest were not reported.

In practice, SCA measured on routine chest radiographs may serve as a simple and readily available radiographic marker for mortality risk assessment in critically ill COPD patients. However, clinicians should interpret these associations cautiously, as they do not establish causation and require validation in larger, prospective studies.