Effects of long-term postoperative dienogest use for treatment of endometriosis on bone mineral density

Objective: This study was conducted to evaluate the effects of long-term postoperative dienogest (DNG) use for the treatment of endometriosis on bone mineral density (BMD). Study design: Sixty reproductive-aged women who underwent conservative surgery for endometriomas and received postoperative DNG (2 mg/day) for at least 12 months to prevent recurrence were analyzed. BMD was measured before and after DNG treatment by using dual energy X-ray absorptiometry, and changes in BMD were evaluated. Results: Mean patient age was 30.5 years, and mean duration of DNG treatment was 18.6 months. BMD at the lumbar spine significantly decreased after the first 6 months (-2.2%), and 1 year (-2.7%) of DNG treatment, compared to baseline. The proportion of women who had significantly decreased BMD at the lumbar spine after 1 year was 75% (45/60). In addition, BMD at the femur neck also decreased significantly after 1 year (-2.8%). BMDs after 2 years were not different from those after 1 year at both sites in 24 women who received DNG for >= 2 years. In addition, there were no differences in baseline characteristics between women who had significantly reduced BMD at the lumbar spine after 1 year (N =45) and women who did not (N = 15). Conclusion: This study suggests that long-term postoperative DNG treatment might have an adverse effect on BMD in reproductive-aged women. Bone loss mostly occurs during the first 6 months of treatment with DNG. A clinical trial is warranted to establish the effects of long-term DNG treatment on bone mass. (C) 2017 Elsevier B.V. All rights reserved.