Objective: This work aims to determine whether discontinuation of hormone therapy (HT) in perimenopausal and postmenopausal women is associated with an increased risk of initiating antidepressant therapy.
Methods: A population-based cohort study was conducted using data from the Swedish Prescribed Drug Register and the Total Population Register for the period July 2005 to June 2009. We included women aged 45 to 70 years who had used HT continuously for more than 6 months before July 2008. Women with previous use of antidepressants since July 2005 were excluded. We compared the incidence rates of initiating antidepressant therapy during HT and after withdrawal of HT. The women were followed from July 2008 until the first dispensing of antidepressants, restart of HT, migration, death, or end of the study period, whichever occurred first. Poisson regression analysis was used to estimate the incidence rate ratios adjusting for potential confounders (age, calendar time, duration of HT use, and number of HT prescriptions).
Results: Of the 101,911 women enrolled in the cohort, 39.8% discontinued HT during follow-up. Discontinuation of HT was associated with an increased risk of antidepressant use (incidence rate ratio, 1.24; 95% CI, 1.11-1.38). Women 65 years or older and women who had used HT for 3 years or more had the highest risk estimates, but effect modification by age and duration was not significant.
Conclusions: We found a slightly increased risk in the use of antidepressant therapy after discontinuation of HT.
From the 1Center for Pharmacoepidemiology, Department of Medicine, Karolinska Institutet, Stockholm, Sweden; 2Medical Products Agency, Uppsala, Sweden; and 3Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
Received March 7, 2012; revised and accepted May 23, 2012.
Funding/support: None reported.
Financial disclosure/conflicts of interest: Dr. Helle Kieler reports financial activities outside the submitted work, such as institutional grants for Post-Authorization safety studies from the Medical Products Agency, Abbott, AstraZeneca, Pfizer, and Merck Sharp and Dohme, as well as institutional grants for travel/accommodations meeting from Astellas. Dr. Morten Andersen reports financial activities outside the submitted work, such as personal grants for a pharmacoepidemiology course from Medicademy and the Danish Association of the Pharmaceutical Industry, as well as institutional grants for pharmacoepidemiological studies from AstraZeneca, Pfizer, and Merck Sharp and Dohme. The other authors did not report any potential conflicts of interest.
This article represents the views of the authors and not necessarily those of Medical Products Agency where one of the authors is employed.
Address correspondence to: Anna Citarella, PhD, Center for Pharmacoepidemiology, Karolinska Institutet, T2, Karolinska University Hospital, SE 171 76 Stockholm, Sweden. E-mail: firstname.lastname@example.org