Current or past HRT users had a an approximately 1.5 greater risk of acute pancreatitis
Acute pancreatitis is a sudden inflammation that occurs over a short period of time. In the majority of cases, acute pancreatitis is caused by gallstones or heavy alcohol use. Other causes include medications, infections, trauma, metabolic disorders, and surgery. In up to 30% of people with acute pancreatitis, the cause is unknown.
Several case reports have suggested that women's use of exogenous sex hormones is associated with acute pancreatitis; however, relevant epidemiologic data are sparse.
Dr. Viktor Oskarsson, Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, and colleagues examined the association between postmenopausal hormone replacement therapy and risk of acute pancreatitis.
In this prospective study, researchers examined data on 31,494 postmenopausal women, aged 48 to 83 years, from the population-based Swedish Mammography Cohort.
All participants completed a questionnaire in 1997 assessing their use of hormone replacement therapy this study ran from 1997 to 2010.
At the start of the study 13,113 (42%) of the women were current users of HRT and 3,360 (12%) were previous users and the remainder had never used the therapy. Of the current users of HRT, 6795 (52%) used systemic therapy for hot flashes, 4148 (32%) used local therapy for vaginal dryness, and 2170 (16%) used both therapies.
A total follow-up of 389, 456 person-years, researchers found 237 cases of incident acute pancreatitis. The age-standardized incidence rates per 100 000 person-years were 71 cases among women who had ever used hormone replacement therapy and 52 cases among women who had never used such hormones.
After taking account of factors likely to influence the results, the team found that women who currently or previously had used HRT had an approximately 1.5 greater risk of acute pancreatitis than those who had never used the therapy. The risk seemed higher among women who used systemic therapy (1.92) and among those with duration of therapy of more than 10 years (1.87).
The researchers write “Use of postmenopausal hormone replacement therapy was associated with increased risk of acute pancreatitis. Physicians should consider this potential increase in risk when prescribing such therapy.”
Dr. Oskarsson writes "There are no contemporary data that might explain our finding that the risk was sustained among past users of [HRT] or that the risk seemed to increase with duration of use.” "These findings, though speculative, may suggest that exogenous estrogen induces some persistent change in the pancreas for which the duration of exposure may be important."
This study appears in CMAJ.