Long-term combination oral contraceptives linked to surgery for Crohn's

Last Updated: 2016-03-14

By Laura Newman

NEW YORK (Reuters Health) - Use of combination birth control pills for more than three years was associated with an increased risk for first Crohn's disease-related surgery, reveals a Swedish National Register study.

The study did not find a significant relationship between current use of oral contraceptives, but the authors wrote that this "may be explained by prior observation in this registry that a substantial percentage of women (approximately 25%) either completely stopped using oral contraceptives or switched to nonhormonal type, particularly intrauterine devices within six months of first oral contraceptive prescription."

"For every 83 patients with Crohn's disease on combination oral contraceptives (OCs) for one or more years, one extra Crohn's disease surgery was required," study leader Dr. Hamed Khalili of Massachusetts General Hospital, Boston, told Reuters Health in a telephone interview.

The researchers had previously shown a link between oral contraceptives and Crohn's disease (CD). The present study, published online February 23 in Gastroenterology, focused on CD progression, i.e., need for surgery and steroid use.

Using Swedish National Patient Register data from 2002 through 2013 and the Swedish Prescribed Drug Register, with data between 2005 and 2013, the research team reviewed birth control pill use and the first CD-related surgery and first steroid prescription in 4,036 women with CD who had no prior surgery at baseline. In this group, 482 surgeries were identified with a median follow-up of 58 months.

In comparison with women who were not taking combination OCs, multivariable-adjusted hazard ratios of surgery came to 1.14 for past users, 1.30 for current users, and 1.68 for users of more than three years. Steroid prescriptions were not linked with past or current use of oral contraceptives.

Based on the findings, Dr. Khalili told Reuters Health, "These medications (combination birth control pills) should be avoided in women with Crohn's."

Dr. Sunanda V. Kane, of the Mayo Clinic, Rochester, Minnesota, viewed the findings differently. In an email to Reuters, she wrote: "The historical data about the risk of OCs causing and/or exacerbating Crohn's disease are conflicting. This is a nice population-based study that was able to follow women prospectively with a hard outcome, i.e. surgery. The authors note their own limitation of the absence of data on disease severity and smoking status, two variables that would influence the clinical course of disease."

Dr. Kane added, "The information from this study may help with discussions regarding contraceptive choices, but should not discourage women from using OCs in the appropriate setting. There are compelling reasons to prescribe OCs, not just for effective contraception. A multitude of different formulations are available and because of a higher thrombotic risk or concomitant liver disease, it is recommended that women avoid those forms with a high estrogen level. Since it is not typically a gastroenterologist that prescribes an OC, the information from this study must be put into clinical context - clinical course and the risk for surgery is still going to be driven predominantly by those clinical variables that are well known, like smoking, uncontrolled inflammation, need for steroids."

Dr. Kane added, "The dataset could not assess for pregnancy desire in addition to the other confounders I already alluded to. They can't confirm that the pills used were the same - combination pills still have different estrogen doses and different progestin types and doses. They compared combination to progestin only, but don't give the number of women on progestin methods and duration of use. These may seem to be trivial points to a gastroenterologist, but when talking about contraceptive health these are important."

Dr. Daniel Grossman, of the University of California, San Francisco, also responded via email to Reuters Health: "The main finding of the paper (past use or current use of OCs and association with surgery or steroid use) was not statistically significant. The only significant finding was related to OC use of more than three years."

Dr. Grossman did not find the findings compelling because as an observational study, "the researchers were not able to control for many known and unknown confounders (including smoking history), which may have affected the results."

Additionally, he pointed out, "For women with ulcerative colitis or Crohn's disease who are considered at increased risk for venous thromboembolism due to extensive disease, surgery, immobilization, steroid use, or other reasons, the risks associated with use of combined oral contraceptives are felt to outweigh the benefits, and other contraceptive options should be considered."

Dr. Grossman continued, "I don't think this study would affect my management. There are a lot of reasons why pills are not the best option for many women - especially those who value efficacy above all else. For them, an (intrauterine device) or implant would be the best method. But for women who prefer the pill for specific reasons and who do not have other contraindications, I think it would be fine to continue using the pill."

Criticisms aside, Dr. Grossman called the findings "interesting" and "deserving of more research." However, he underscored, "They should not cause every woman with Crohn's to stop taking her pills. Unintended pregnancy is also risky for women with Crohn's."

The Crohn's and Colitis Foundation of America and other organizations supported this research.

SOURCE: http://bit.ly/1UbMw1P

Gastroenterology 2016.