Non-steroidal anti-inflammatory drugs and venous thromboembolism in women

Non-steroidal anti-inflammatory drugs (NSAIDs) might increase the risk of venous thromboembolism (VTE), and risks might differ by type of NSAID. Compared with men, women have a higher incidence of VTE at younger age, and they more often use NSAIDs.

To assess risks of VTE in young and middle-aged women in association with use of NSAIDs.

In a nationwide case–control study (Thrombo Embolism Hormone Study) performed in Sweden 2003–2009, we included as cases 1433 women, 18 to 64 years of age with a first time VTE. Controls were 1402 randomly selected women, frequency matched by age. Information was obtained by telephone interviews and DNA analyses of blood samples. We calculated adjusted odds ratios (ORs) with 95% confidence intervals (CIs) adjusting for degree of immobilization, chronic disease, smoking, body mass index, use of hormonal contraception, hormone therapy or other NSAIDs.

Use of NSAIDs was not associated with increased risks of VTE (OR = 0.98, 95% CI 0.80–1.19). The OR was 0.88 for propionic acid derivatives (95% CI 0.72–1.10), 1.18 for acetic acid derivatives (95% CI 0.82–1.70) and 1.76 for coxibs (95% CI 0.73–4.27). For users of acetic acid derivatives and coxibs, the ORs increased by cumulative dose. Carriership of the prothrombin gene mutation or factor V Leiden had only minor effects on the results.

We found no increased risks of VTE in association with use of NSAIDs. Users of high cumulative doses of acetic acid derivatives and coxibs had the highest risks, suggesting a relationship with cyclooxygenase selectivity and dose.