Incidence of venous thromboembolism following initiation of non-steroidal anti-inflammatory drugs in U.S. women.
OBJECTIVE
To evaluate the risk of venous thromboembolism (VTE, i.e. deep vein thrombosis or pulmonary embolism, or both) following new use of NSAIDs in a long-term cohort of U.S. women.


METHODS
We investigated initiation of coxibs and traditional NSAIDs (excluding aspirin) and incident VTE in 39 876 women enrolled in the Women's Health Study from 1993-95 and followed with yearly questionnaires until 2012. We defined initiation as the first reported use of NSAIDs for ≥4 days per month. Incident VTE was confirmed by an end point committee. We estimated hazard ratios (HRs) and risk differences (RDs, expressed as percentages) comparing NSAID initiation with non-initiation and acetaminophen initiation (active comparator) via standardization using a propensity score that incorporated age, BMI, calendar time, and relevant medical, behavioural, and socioeconomic variables updated over time.


RESULTS
The HR (95% CI) for risk of VTE in the as treated analyses comparing initiation with non-initiation, was 1.5 (1.2, 1.8) for any NSAID, 1.3 (1.1, 1.7) for traditional NSAIDs, and 2.0 (1.3, 3.1) for coxibs, with 2-year RDs 0.11, 0.08 and 0.32, respectively. When comparing the risk of VTE after initiation of any NSAID with that after acetaminophen initiation, the HRs were 0.9 (0.6, 1.5), 0.9 (0.5, 1.5) and 1.4 (0.6, 3.4), with 2-year RDs 0.03, -0.01, and 0.13, respectively.


CONCLUSION
New use of NSAIDs was associated with increased VTE risk compared with non-use, but the association was null or diminished when compared with acetaminophen initiation. Elevated VTE risks associated with NSAID use in observational studies may in part reflect different baseline risks among individuals who need analgesics and may overstate the risk patients incur compared with pharmacologic alternatives.
['Kinsey|Tracy L|TL|', 'Stürmer|Til|T|', 'Funk|Michele Jonsson|MJ|', 'Poole|Charles|C|', 'Simpson|Ross J|RJ|', 'Glynn|Robert J|RJ|']
D000082:Acetaminophen D018712:Analgesics, Non-Narcotic D000894:Anti-Inflammatory Agents, Non-Steroidal D052246:Cyclooxygenase 2 Inhibitors D005260:Female D006801:Humans D015994:Incidence D000069451:Long Term Adverse Effects D008875:Middle Aged D017891:Pharmacoepidemiology D011655:Pulmonary Embolism D018570:Risk Assessment D014481:United States D020246:Venous Thrombosis
venous thromboembolism non-steroidal anti-inflammatory drugs deep vein thrombosis pulmonary embolism NSAIDs pharmacoepidemiology