Identification of patients operated on for menorrhagia
The first step consisted in identifying within the PMSI-MCO database all the hospitalizations of 35-55 year-old women who had a first surgical management of menorrhagia in France from 1st January 2009 until 30th June 2014. Detailed information’s regarding the algorithm used has already been described21. Briefly, stays for surgical treatment (with a CCAM code figuring in the Sup. Table 1) as PD or RD in patients with menorrhagia (with an ICD-10 code figuring in the Sup. Table 2) were selected. Patients already operated on for menorrhagia surgery were excluded, to include incident patients only. Any patient identified as presenting comorbidities, concomitant conditions (breast or colorectal cancer), treatments potentially causes of bleeding (Willebrand disease, myoma respectively, C and L of new terminology5), as well as patients with gynecological cancers, alcoholic liver, gynecological and pelvic infections and inflammation, endometriosis, uro-gynaecological prolapse, fistulas, polyps and dysplasia, infertility, pregnancy, spina bifida, iatrogenic causes (I of new terminology5) or blood diseases were excluded as they would introduce bias.
Stays were classified into one of four categories of surgical techniques to treat AUB-O,E,N according to the CCAM code (Online supporting material 1): (i) second-generation (2G) endometrial ablation techniques such as radiofrequency ablation or balloon thermodestruction,(ii) first-generation (1G) endometrial ablation and/or resection techniques, such as loop resection and/or roller ball, (iii)curettage and (iv) hysterectomy. Thanks to their unique anonymous identifier, all patients were followed from their initial surgery for at least 18 months and up to date point (31/12/2015) or death, in order to detect any severe complications or failure.