Risk factors for pulmonary embolism: a case-control study

Pulmonary embolism (PE) is characterized by a high rate of misdiagnosis and poor prognosis. This descriptive epidemiological study aimed to identify modifiable risk factors for PE through an age- and sex-matched case-control study.

The case group consisted of patients diagnosed with PE at Beijing Anzhen Hospital, within a 3-year period. Age- and sex-matched controls were randomly selected from individuals who participated in health check-ups at the same institute during the same period. Clinical variables, including histories of hypertension, diabetes, body mass index (BMI), smoking, systolic blood pressure (SBP), and obstructive sleep apnea-hypopnea syndrome (OSAHS), were analyzed in 129 case-control pairs.

In univariate analysis, significant risk factors for PE included OSAHS, smoking, triglycerides, and estimated glomerular filtration rate (eGFR). In multivariate analysis, using a conditional logistic regression model, OSAHS [P=0.01; odds ratio (OR), 3.100; 95% confidence interval (CI): 1.202-7.994], hypertension (P=0.02; OR, 2.212; 95% CI: 1.107-4.420), and smoking (P<0.001; OR, 7.167; 95% CI: 3.302-15.556) were identified as independent risk factors for PE. No significant associations were observed between triglycerides or eGFR and PE. Additionally, a negative correlation between arterial partial pressure of carbon dioxide (PCO₂) and PE was observed in the multivariate analysis (P=0.02; OR, 0.946; 95% CI: 0.904-0.990). A risk model and scoring system with strong discriminatory power were developed (adjusted OR, 1.129; 95% CI: 1.021-1.248).

The findings suggest that OSAHS, hypertension, and smoking are strongly associated with PE, while arterial PCO₂ may exhibit a protective correlation with PE risk.