Risk factors and prognosis of postoperative cardiac events in elderly patients with hip fractures: a retrospective cohort study

Background Postoperative cardiac events (PCEs) are life-threatening in elderly patients undergoing hip fracture surgery. This study aimed to analyze the risk factors for PCEs in these patients and to investigate the impact of PCEs on the outcomes. Methods A retrospective review of consecutive patients who underwent surgeries for hip fractures at the Seventh Medical Center, Chinese PLA General Hospital from January 2012 to December 2020 was performed. The patients were divided into a PCEs group or a non-PCEs group according to whether they experienced PCEs. Univariate and multivariate logistic regression analysis was employed to investigate the independent risk factors for PCEs. In addition, the all-cause mortality and cardiogenic mortality within 30 days and 1 year after surgery were compared between the two groups. Results We eventually recruited 1718 patients, and 169 patients (9.8%) experienced PCEs. Acute heart failure (66.9%, 113/169) was the most common PECs, followed by major arrhythmia (18.9%, 32/169) and acute coronary syndrome (14.2%, 24/169). Age > 80 years (OR = 1.515, 95% CI = 1.046–2.193, P  = 0.028), male sex (OR = 1.605, 95% CI = 1.130–2.279, P  = 0.008), a history of arrhythmia (OR = 1.942, 95% CI = 1.291–2.920, P  = 0.001), a blood transfusion volume over 2 U (OR = 1.489, 95% CI = 1.016–2.181, P  = 0.041) and an ASA classification of III or IV (OR = 1.869, 95% CI = 1.289–2.709, P  = 0.001) were independent risk factors for PCEs. The 30-day all-cause mortality rate and the proportion of cardiac deaths were12.4% (21/169) and 71.4% (15/21) in patients with PCEs, which were significantly higher than those of 3.2% (50/1549) and 30% (15/50) in patients without PCEs (both P  < 0.001), and the difference was retained at 1 year. Conclusions PCEs were not uncommon in elderly patients undergoing hip fracture surgery. Older age, male sex, a history of arrhythmia, a large volume of blood transfusion and a higher ASA classification were independent risk factors for PCEs, and patients with PCEs had higher short- and long-term mortality. Strengthening perioperative care should be considered to avoid potential PCEs in patients with the above risk factors.