PURPOSE: We sought to study the relationship between obstructive sleep apnea (OSA) and venous thromboembolism (VTE).
METHODS: We reviewed the electronic medical records of patients who had a sleep related illness or underwent a polysomnography (PSG) study at a tertiary university hospital. OSA was defined by one of the following criteria: Apnea Hypopnea index (AHI) of >=5 /hour or past medical history clearly listing a diagnosis of OSA. Charts were reviewed for baseline characteristics including demographics, body mass index (BMI), smoking status and co- morbid conditions. Primary outcome was the prevalence of VTE. Stratified multivariate analysis was performed on the cohort according to gender.
RESULTS: 1584 patients were included in this analysis. Females comprised 848 (46.5%) of patients. Majority of patients had documented PSG study (1338, 84%). Only 10.6% had historic or current malignancy. Of this cohort, 1124(71%) had OSA and 77(4.9%) had VTE. Patients with OSA trended towards higher prevalence of VTE than controls (5.4% vs. 3.5%; p=0.063). Patients with VTE were more likely to be older, have additional cardiovascular pathology and higher BMI in the obese range (defined as BMI≥ 30) than their counterparts. Patients with both OSA and obesity had the highest prevalence of VTE (6.5%). In gender-stratified multivariate analysis, we adjusted for obesity, malignancy, race, cardiovascular, lung or renal disease, stroke, and age. We found that OSA was an independent risk factor for VTE among females [odds ratio 2.69 (1.03-7.04) P=0.043] but not among males.
CONCLUSION: OSA is an independent risk factor for VTE among females and not among males. Our findings are limited by the retrospective design; however, we report the largest cohort to date in the literature.
CLINICAL IMPLICATIONS: OSA should be added to list of risk factors for VTE, especially among females. The combination of OSA and obesity seems to play a synergistic role in the development of VTE. Further studies are necessary to evaluate gender variation effect on OSA and VTE relationship.
DISCLOSURE: Ousama Dabbagh, Consultant fee, speaker bureau, advisory committee, etc. Ousama Dabbagh is on the speaker bureau : SANOFI -AVENTIS; No Product/Research Disclosure Information