Endometriosis · Diagnosis

Incidence of endometriosis by study population and diagnostic method: the ENDO study

Buck Louis GM, Hediger ML, Peterson CM, Croughan M, Sundaram R, Stanford J, Chen Z, Fujimoto VY, Varner MW, Trumble A, Giudice LC, ENDO Study Working Group

Published July 2, 2011 Fertility and Sterility, 96(2), 360-365
DOI 10.1016/j.fertnstert.2011.05.087 PMID 21719000 PMC PMC3143230
Read our synopsis

RRM Academy Synopsis

Endometriosis in surgery patients ranged from 0.7% to 41% by method

Endometriosis incidence depended on the diagnostic method used, a matched cohort of 495 surgery patients and 131 local women found. In surgery patients, 0.7% had disease found only on histology, with none seen at surgery (1 of 143 biopsied). MRI alone found 7%, and visualized disease 41%. MRI found it in 11% of women sampled from the population.

Key Findings

  • Among surgery patients, 0.7% had disease found only on histology, with none seen at surgery (1 of 143). MRI only found 7% (7 of 96) and any visualization 41% (192 of 473).
  • Among the 32 surgery patients with visualization, histology and MRI all available, 34% (11 of 32) had endometriosis diagnosed by all three methods.
  • By the point-score algorithm, 58% of surgery patients with endometriosis had minimal disease (107 of 185) and 15% had mild disease (27 of 185).
  • Surgeon and algorithm staging agreed for 60% of women across all stages, rising to 84% when staging was grouped as minimal/mild versus moderate/severe.
  • In the population cohort, MRI-diagnosed endometriosis incidence was 11% (14 of 127).

Interpretation

The ENDO Study is an observational matched cohort: women having surgery at Utah and California centers, compared with women sampled from the same areas. Each diagnostic method ran on a different subset of women, so each rate has its own denominator. Biopsies were optional for surgeons, and a random sample of 96 surgery patients had MRI. The population group had MRI only and no staging. The authors could not assess false positives there and call 11% likely an underestimate. Surgery patients were menstruating women aged 18 to 44, and the population group was matched to them on age and area.

RRM Context

Restorative reproductive medicine evaluates the cause before it treats. The method of evaluation sets what a clinician can find, and the same surgery cohort produced very different incidence figures by method. The population group adds an MRI estimate of at least 11% in women with no surgical diagnosis. Excision is the surgical standard.

Abstract

Objective

To estimate the incidence of endometriosis in an operative cohort of women seeking clinical care and in a matched population cohort to delineate more fully the scope and magnitude of endometriosis in the context of and beyond clinical care.

Design

Matched-exposure cohort design.

Setting

Surgical centers in the Salt Lake City, Utah, and San Francisco, California, areas.

Patients

The operative cohort comprised 495 women undergoing laparoscopy/laparotomy between 2007 and 2009, and the population cohort comprised 131 women from the surgical centers' catchment areas.

Interventions

None.

Main Outcome Measures

Incidence of endometriosis by diagnostic method in the operative cohort and by pelvic magnetic resonance imaged (MRI) disease in the population cohort.

Results

Endometriosis incidence in the operative cohort ranged by two orders of magnitude by diagnostic method: 0.7% for only histology, 7% for only MRI, and 41% for visualized disease. Endometriosis staging was skewed toward minimal (58%) and mild disease (15%). The incidence of MRI-diagnosed endometriosis was 11% in the population cohort.

Conclusions

Endometriosis incidence is dependent on the diagnostic method and choice of sampling framework. Conservatively, 11% of women have undiagnosed endometriosis at the population level, with implications for the design and interpretation of etiologic research.

Topics

By this author

Related research

Endometriosis › Diagnosis › Imaging
Germaine M Buck Louis, C Matthew Peterson, Rajeshwari Sundaram, Zhian Chen, Michael W Varner, Linda C Giudice, Victor Y Fujimoto, Mary L Hediger, Joseph B Stanford
G Louis, R Sundaram, Z Chen, Mike Varner, M Varner, L Giudice, V Fujimoto, M Hediger, Joe Stanford, Joey Stanford, J Stanford
PMID 21719000 21719000 DOI 10.1016/j.fertnstert.2011.05.087 10.1016/j.fertnstert.2011.05.087 Buck Louis et al. 2011, Buck Louis 2011

Cite this article

Buck Louis, G. M., Hediger, M. L., Peterson, C. M., Croughan, M., Sundaram, R., Stanford, J., Chen, Z., Fujimoto, V. Y., Varner, M. W., Trumble, A., Giudice, L. C., & ENDO Study Working Group (2011). Incidence of endometriosis by study population and diagnostic method: the ENDO study. Fertility and Sterility, 96(2), 360-365. https://doi.org/10.1016/j.fertnstert.2011.05.087