Risk factors associated with the false positive of cardiopulmonary exercise test in the diagnosis of coronary heart disease.

Purpose: Cardiopulmonary exercise test (CPET) is a common method for preliminary evaluating coronary heart disease (CHD), but it may experience false positive. The present study aimed to reveal the potential factors relating to the false positive of CPET, including blood glucose and lipids.

Methods: This observational cohort study included 103 subjects with false positive of CPET and 65 subjects with true positive of CPET. The baseline characteristics, blood glucose, and blood lipids between the true and false positive groups were compared. After adjusting for the age and sex, logistic regression analysis was performed to reveal the potential risk factors of false positive. Receiver operating characteristic curve analysis was performed to evaluate the potential of related factors in distinguishing between true and false positive results.

Results: Males, smokers, and patients with diabetes were less likely to suffer from false positive of CPET. Compared with the true positive group, the false positive group exhibited significantly higher levels of high-density lipoprotein (HDL) and apolipoprotein A1 (Apo-A1), and lower levels of fasting blood glucose (FBG) and glycosylated hemoglobin (GHb). After adjustment, FBG and GHb were protective factors of the true positive of CPET, and they both had moderate ability to distinguish false positive from true positive in females. However, their combination did not improve the discriminative effect more obviously than FBG alone.

Conclusions: Sex, smoking, diabetes, and blood glucose were associated with the false positive of CPET. FBG was valuable in predicting the risk of false positive of CPET in females with suspected CHD.

Trial registration: The present study is registered in Chinese Clinical Trial Register (ChiCTR2400089239).