Yu Chen: Department of Cardiology, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China.
Yan-Kun Shi: Department of Cardiology, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China.
Shi-Zhong Fu: Department of Infectious Diseases, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China.
Zhuo-Dong Li: Department of Thoracocardiac Surgery, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China.
Sheng-Yu Yang: Department of Urology, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China.
Xiao-Ying Zhou: Department of pediatrics, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China.
Zhu Yan: Department of Cardiology, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China.
Chun-Ping Bao: Department of Cardiology, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China.
Xin-Ming Xu: Department of Quality Control, 920th Hospital of Joint Logistics Support Force, PLA, No. 212 Daguan Rd, Kunming, 650032, Yunnan, China. kzxxm@126.com.
Xin Zhang: Department of Pulmonary and Critical Care Medicine, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China. derekzhang2008@163.com.
Li-Xia Yang: Department of Cardiology, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China. doctorylixia@aliyun.com.
BACKGROUND: Exposure to high altitude increases the risk of myocardial ischemia (MI) and subsequent cardiovascular death. Nomogram is a graphical regression model, but there are no reports on using nomogram to predict myocardial ischemia under high altitude exposure. Our goal was to establish prediction models based on pre-high-altitude physical exposure examination data and identify key risk factors. METHODS: We prospectively enrolled a total of 2,855 healthy individuals who underwent physical examination at the 920th Hospital of Joint Logistics Support Force and were scheduled to undergo high-altitude (3000-3500 m) training within six months. These participants were randomly divided into a training cohort (75%) and a validation cohort (25%). In the training set, single-factor analysis of variance and Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis were used to select variables, and two nomograms were established based on clinical features (CF) and clinical features + blood tests (CF + BT), respectively. The performance of the nomograms was evaluated using the area under the receiver operating characteristic curve (ROC), the concordance index (C-index), and calibration curves. RESULTS: The C-index for the prediction models CF and CF + BT were 0.652 and 0.804, respectively. In the training cohort, the AUC for prediction models CF and CF + BT were 0.61 and 0.80, respectively. In the validation cohort, the AUC for prediction models CF and CF + BT were 0.61 and 0.81, respectively. CONCLUSION: We have successfully established two nomogram models to predict myocardial ischemia under high-altitude exposure and identified some risk factors.
