RESUMEN
Dienogest (DNG) is a progestin with highly selective progesterone activity and known to be effective in the treatment of endometriosis. This prospective cohort study in patients who had been treated with DNG 2 mg (Visanne®) for endometriosis was conducted to assess the safety and effectiveness of DNG in a large Korean cohort. This study included 3356 patients with endometriosis from 73 centers in Korea. All patients were treated with DNG 2 mg daily and were followed up for at least 6 months after initial visit. Any adverse events were recorded including severity, onset/closing date, outcomes, treatments, and the causality with DNG. Effectiveness of DNG was measured by changes in visual analogue scale (VAS) from baseline at the end of follow-up. The mean age of the subjects was 34.96 years, and the mean duration of treatment was 285.44 days. Incidence of adverse drug reaction (ADR) was 13.27% (413/3113). The most frequently reported ADR were "abnormal uterine bleeding" 4.14% (129/3113), "increased weight" 2.57% (80/3113), and "headache" 1.22% (38/3113). The number of patients (%) with favorable bleeding patterns was observed to increase as the duration of treatment increases. Amenorrhea was observed in 29.63%, 41.25%, 46.26%, and 53.20% of patients at 3 months, 6 months, 12 months, and more than 12 months follow-up period, respectively. The mean (±SD) VAS change from baseline at the last follow-up visit was -28.19 ± 28.39 mm (P value < 0.0001). This large cohort study confirms, in routine clinical practice, that DNG is safe and effective for treatment of endometriosis.