title: Probability of hysterectomy after endometrial ablation.
abstract: OBJECTIVE
  To investigate risk factors for hysterectomy after endometrial ablation.
  
  
  METHODS
  This was a retrospective cohort analysis of data from Kaiser Permanente Northern California members, aged 25-60 years undergoing endometrial ablation from 1999 to 2004 and collected through 2007. Risk factors assessed included age, presence of leiomyomas, setting of procedure (inpatient or outpatient), and type of endometrial ablation procedure (first generation, radio frequency, hydrothermal, or thermal balloon). Univariable and survival analyses were performed to identify risk factors and estimate probability of hysterectomy.
  
  
  RESULTS
  From 1999 to 2004, 3,681 women underwent endometrial ablation at 30 Kaiser Permanente Northern California facilities. Hysterectomy was subsequently performed in 774 women (21%), whereas 143 women (3.9%) had uterine-conserving procedures. Age was a significant predictor of hysterectomy (P<.001). Cox regression analysis found that compared with women aged older than 45 years, women aged 45 years or younger were 2.1 times more likely to have hysterectomy (95% confidence interval 1.8-2.4). Hysterectomy risk increased with each decreasing stratum of age and exceeded 40% in women aged 40 years or younger. Overall, type of endometrial ablation procedure, setting of endometrial ablation procedure, and presence of leiomyomas were not predictors of hysterectomy. In analysis of individual procedure types, concomitant myomectomy was associated with a decreased risk of hysterectomy for patients receiving first-generation endometrial ablation (P=.002), and outpatient location for hydrothermal endometrial ablation increased hysterectomy risk (P<.001).
  
  
  CONCLUSIONS
  Age is more important than type of procedure or presence of leiomyomas in predicting subsequent hysterectomy after endometrial ablation. Women undergoing endometrial ablation at younger than 40 years of age are at elevated risk of hysterectomy, and rather than plateauing within several years of endometrial ablation, hysterectomy risk continues to increase through 8 years of follow-up.
  
  
  METHODS
  II.
authors.affiliation: From the Department of Obstetrics and Gynecology and Division of Research, Kaiser Permanente Northern California, San Francisco, California; and Department of Obstetrics and Gynecology, Indiana University School of Medicine, Bloomington, Indiana.
authors.forename: Mindyn K
authors.initials: MK
authors.lastname: Longinotti
authors.forename: Gavin F
authors.initials: GF
authors.lastname: Jacobson
authors.forename: Yun-Yi
authors.initials: YY
authors.lastname: Hung
authors.forename: Lee A
authors.initials: LA
authors.lastname: Learman
mesh_terms: D000328:Adult; D015331:Cohort Studies; D055356:Endometrial Ablation Techniques / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007044:Hysterectomy; D015993:Life Tables; D008595:Menorrhagia / Q000601:surgery*; D008875:Middle Aged; D011336:Probability; D012189:Retrospective Studies; D017211:Treatment Failure