Nonsteroidal anti-inflammatory drugs increase the risk of pulmonary embolism

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used with an easy over-the-counter availability. NSAIDs are associated with an increased risk for arterial thrombosis, particularly for Cox-2-selective drugs (COXIBs), but their effect on venous thrombotic events is less well established. The objective of this study was to assess the risk of different types of NSAIDs on pulmonary embolism (PE). Methods: A case-control study was conducted using data from the PHARMO Record Linkage System, a population-based registry of pharmacy records linked with hospital discharge records in the Netherlands. Cases were patients hospitalized with a primary diagnosis of PE between 1998 and 2006. Up to four controls were matched to each case. All patients had at least 1 year of exposure history prior to the index date (date of admission). Logistic regression analysis was used to assess the strength of the association between use of NSAIDs and PE. Results: The study population comprised of 4.495 cases and 16.802 controls. The median age of the cases was 60 years (range 18-96) and 57% were females. Use of NSAIDs was more prevalent among cases (10%) than controls (4%). After adjustment for confounding factors, such as surgery, trauma, and malignancy, this association persisted: OR 3.11, 95%CI 2.71-3.57. Past use (> 6 months prior to index date) of NSAIDs was less strongly associated with PE (OR 1.17, 95%CI 1.08-1.27). Stratification according to type of NSAID showed a higher risk for traditional NSAIDS than for COXIBs (adjusted OR of 3.32 (95%CI 2.86-3.85) and 1.74 (95%CI 1.21-2.51), respectively). Conclusion: NSAIDs were associated with an increased risk of PE, with a higher risk for traditional NSAIDs compared with COXIBs. This risk of PE was highest with current use of NSAIDs. Considering the common use of these drugs, the attributable risk in the population could be considerable. Disclosure of interest: none declared.