Validity of Self-reported Endometriosis

A Comparison Across Four Cohorts

A.L. Shafrir; L.A. Wise; J.R. Palmer; Z.O. Shuaib; L.M. Katuska; P. Vinayak; M. Kvaskoff; K.L. Terry; S.A. Missmer

Hum Reprod. 2021;36(5):1268-1278.

Abstract and Introduction

Abstract

Study Question: How accurately do women report a diagnosis of endometriosis on self-administered questionnaires?

Summary Answer: Based on the analysis of four international cohorts, women self-report endometriosis fairly accurately with a > 70% confirmation for clinical and surgical records.

What is Known Already: The study of complex diseases requires large, diverse population-based samples, and endometriosis is no exception. Due to the difficulty of obtaining medical records for a condition that may have been diagnosed years earlier and for which there is no standardized documentation, reliance on self-report is necessary. Only a few studies have assessed the validity of self-reported endometriosis compared with medical records, with the observed confirmation ranging from 32% to 89%.

Study Design, Size, Duration: We compared questionnaire-reported endometriosis with medical record notation among participants from the Black Women's Health Study (BWHS; 1995–2013), Etude Epidémiologique auprès de femmes de la Mutuelle Générale de l'Education Nationale (E3N; 1990–2006), Growing Up Today Study (GUTS; 2005–2016), and Nurses' Health Study II (NHSII; 1989–1993 first wave, 1995–2007 second wave).

Participants/Materials, Setting, Methods:Participants who had reported endometriosis on self-administered questionnaires gave permission to procure and review their clinical, surgical, and pathology medical records, yielding records for 827 women: 225 (BWHS), 168 (E3N), 85 (GUTS), 132 (NHSII first wave), and 217 (NHSII second wave).

Table I. Population characteristics and validation study eligibility of the Black Women's Health Study, Etude Epidémiologique aupres de femmes de la Mutuelle Générale d l'Education Nationale, Growing Up Today Study, and Nurses' Health Study II.
	BWHS	E3N	GUTS	NHSII first wave	NHSII second wave
Enrollment years	1995	1989–1991	1996 & 2004	1989	1989
Age range at baseline (yrs)	21–69	39–66	9–17	25–42	25–42
Baseline population (N)	59,001	98,995	15,044	116,429	116,429
Post-high school education (%)	83%	87%	98%	100%	100%
Questionnaire cycles of endometriosis self-report	1995–2013	1990–2005	2005–2016	1989–1993	1989–2007
Total self-reported endometriosis cases (N)	1,605	2,104	491	1,766	9,452
Endometriosis case type for validation¹	Incident	Incident	Incident & prevalent	Incident	Incident & prevalent
Eligible endometriosis cases (N)²	1,605	558	491	1,766	711
Endometriosis cases selected for validation study (N)	1,605	200	380	200	711

BWHS, Black Women's Health Study; E3N, Etude Epidémiologique aupres de femmes de la Mutuelle Générale d l'Education Nationale; GUTS, Growing Up Today Study; NHSII, Nurses' Health Study II.
¹Participants were considered to have prevalent endometriosis if they reported their endometriosis had been diagnosed before baseline. Incident endometriosis cases were diagnosed after baseline.
²Number of self-reported endometriosis cases eligible for inclusion in the cohort's case validation study.

Table II. Physician, surgical, and pathology record receipt and confirmation proportions by cohort.
Cohort	BWHS	E3N	GUTS	NHSII first wave	NHSII second wave
Baseline population	59 001	98 995	15 044	116 429	116 429
Years in which endometriosis was self-reported	1995–2013	1990–2005	2005–2016	1989–1993	1989–2007
Years when participants were contacted for validation	2008–2016	2007	2011–2017	1996	2009–2011
Eligible women who self-reported endometriosis (N)	1605	558	491	1766	711
Contacted for medical record review (N)	1605	200	380	200	711
Unable to contact/never responded¹	1128	—	139	16	169
Denied diagnosis on consent form	200	—	64	3	77
Confirmed diagnosis but not access to medical records²	—	—	61	32	15
Permission obtained to review medical records³	277 (19.7%)	183 (91.5%)	116 (36.7%)	149 (75.6%)	360 (56.8%)
Medical records never received	52	0	27	17	132
Inadequate information received⁴	0	15	4	0	11
Relevant medical records received and reviewed	225/277 (81.2%)	168/183 (91.8%)	85/116 (73.3%)	132/149 (88.6%)	217/360 (60.3%)
Found no clinical diagnosis and no surgery performed	18	—	4	12	3
Clinical diagnosis noted but no surgery performed⁵	28	—	16	14	4
Surgically confirmed	134	137	63	98	185
Clinical diagnosis noted but disconfirmed at surgery⁶	0	—	2	8	2
Found no clinical diagnosis and disconfirmed at surgery	45	—	0	0	8
Pathology-confirmed but not visualized at surgery	0	—	0	0	9
Pathology-confirmed but no surgical report obtained	0	—	0	0	6
Overall confirmation proportion ⁷	162/225 (72.0%)	137/168 (81.5%)	81/85 (95.3%)	112/132 (84.8%)	206/217 (94.9%)
Surgically confirmed proportion⁸	134/179 (74.9%)	137/168 (81.5%)	63/65 (96.9%)	98/106 (92.5%)	185/204 (90.7%)
Clinically confirmed proportion⁹	18/28 (64.3%)	—	16/20 (80.0%)	14/26 (53.8%)	4/7 (57.1%)

¹Number of participants we were either unable to contact or never responded to repeated mailings.
²These participants confirmed their endometriosis diagnosis but either denied access to their medical records or did not respond to requests for access.
³The percentage providing permission to obtain medical records was calculated out of the total contacted minus those who denied their endometriosis diagnosis.
⁴Reasons inadequate information was received for medical records included no information on disease history and symptoms or medical records not relating to primary care physician, surgeon or gynecologic visits.
⁵Evidence found in the medical records that the participant had been told by her clinician that she most likely had endometriosis but no evidence that she ever had surgery to confirm her diagnosis.
⁶The eight surgically disconfirmed endometriosis cases in the NHSII first wave were all clinically confirmed (found documentation that the woman was told by her clinician that she most likely had endometriosis) and included in the overall and the clinically confirmed proportion.
⁷The numerator of this measure includes those who were surgically confirmed and clinically confirmed.
⁸The denominator of this measure includes those who had evidence of surgery in their medical records.
⁹The denominator of this measure includes those who did not have evidence of surgery in their medical records.

Table III. Differences in surgical and physician confirmation proportions by self-reported laparoscopic confirmation. ¹
Cohort	GUTS	NHSII first wave	NHSII second wave
	Reported Laparoscopic Confirmation
Medical records received and reviewed (N)	64	105	210
Found no clinical diagnosis and no surgery performed	1	0	3
Clinical diagnosis noted but no surgery performed²	3	0	3
Surgically confirmed	59	97	180
Clinical diagnosis noted but disconfirmed at surgery³	1	8	2
Found no clinical diagnosis and disconfirmed at surgery	0	0	8
Pathology-confirmed but not visualized at surgery	0	0	9
Pathology-confirmed but no surgical report obtained	0	0	5
Overall confirmation proportion ⁴	63/64 (98.4%)	105/105 (100%)	199/210 (94.8%)
Surgically confirmed proportion⁵	59/60 (98.3%)	97/105 (92.4%)	180/199 (90.5%)
Clinically confirmed proportion⁶	3/4 (75.0%)	—	3/6 (50.0%)
	Did Not Report Laparoscopic Confirmation ⁷
Medical records received and reviewed (N)	20	27	7
Found no clinical diagnosis and no surgery performed	3	12	0
Clinical diagnosis noted but no surgery performed²	13	14	1
Surgically confirmed	3	1	5
Clinical diagnosis noted but disconfirmed at surgery	1	0	0
Found no clinical diagnosis and disconfirmed at surgery	0	0	0
Pathology-confirmed but not visualized at surgery	0	0	0
Pathology-confirmed but no surgical report obtained	0	0	1
Overall confirmation proportion	17/20 (85.0%)	15/27 (55.6%)	7/7 (100%)
Surgically confirmed proportion^5,8	3/4 (75.0%)	1/1 (100%)	5/5 (100%)
Clinically confirmed proportion⁶	13/16 (81.3%)	14/26 (53.8%)	1/1 (100%)

¹Participants who reported laparoscopic confirmation of their endometriosis diagnosis on self-administered questionnaires.
²Evidence in the medical records that the participant had been told by her clinician that she most likely had endometriosis but no evidence that she ever had surgery to confirm her diagnosis.
³The eight surgically disconfirmed cases in the NHSII first wave were all clinically confirmed (found documentation that the woman was told by her clinician that she most likely had endometriosis) and included in the physician confirmation proportion.
⁴The numerator of this measure included those who were surgically confirmed and clinically confirmed.
⁵The denominator of this measure includes those who had evidence of surgery in their medical records.
⁶The denominator of this measure includes those who did not have evidence of surgery in their medical records.
⁷Total N does not add up to 21 for GUTS as one participant was missing laparoscopic confirmation status self-report and therefore could not be stratified.
⁸Evidence of surgery was found for 11 of the participants who did not self-report having had a laparoscopic confirmation. For the one participant from NHSII first wave and five participants from NHSII second wave, all had hysterectomies at which the presence of endometriosis was documented. For the four GUTS participants, three of them had self-reported a clinical diagnosis that preceded the data of the medical record documentation of laparoscopic surgery and one had a tubal ligation during which endometriosis was visualized.

Authors and Disclosures

A.L. Shafrir^1,2,*, L.A. Wise³, J.R. Palmer^4,5, Z.O. Shuaib⁶, L.M. Katuska⁷, P. Vinayak⁸, M. Kvaskoff^9,10, K.L. Terry^2,8,11 and S.A. Missmer^1,2,8,12

¹Division of Adolescent and Young Adult Medicine, Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA ²Boston Center for Endometriosis, Brigham and Women's Hospital and Boston Children's Hospital, Boston, MA, USA ³Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA ⁴Slone Epidemiology Center, Boston University, Boston, MA, USA ⁵Section of Hematology-Oncology, Boston University School of Medicine, Boston, MA, USA ⁶Massachusetts Department of Public Health, Boston, MA, USA ⁷Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA ⁸Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, USA ⁹CESP, Fac de médecine—Univ. Paris-Sud, Fac. de médecine—UVSQ, INSERM, Université Paris-Saclay, Villejuif Cedex, France ¹⁰Gustave Roussy, Espace Maurice Tubiana, Villejuif Cedex, France ¹¹Department of Obstetrics and Gynecology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA ¹²Department of Obstetrics, Gynecology, and Reproductive Biology, College of Human Medicine, Michigan State University, Grand Rapids, MI, USA

*Correspondence address
Boston Children's Hospital, 1 Autumn Street, 5th Floor, Boston, MA 02215, USA. E-mail: amy.shafrir@childrens.harvard.edu

Authors' roles
S.A.M. designed the study with critical discussions from L.A.W., J.R.P., and M.K., A.L.S., L.A.W., J.R.P., Z.O.S., L.M.K., P.V., M.K., and S.A.M. contributed to the data collection and execution of the study with A.L.S., Z.O.S., L.M.K., P.V., and M.K. contributing to the statistical analyses. A.L.S., L.A.W., J.R.P., M.K., K.L.T., and S.A.M. contributed to the interpretation of the data. A.L.S. drafted the original manuscript version and all authors contributed to reviewing and editing the final manuscript draft.

Conflict of interest
L.A. Wise has served as a fibroid consultant for AbbVie, Inc for the last 3 years and has received in-kind donations (e.g. home pregnancy tests) from Swiss Precision Diagnostics, Sandstone Diagnostics, Kindara.com, and FertilityFriend.com for the PRESTO cohort. SA Missmer serves as an advisory board member for AbbVie and a single working group service for Roche; neither are related to this study. No other authors have a conflict of interest to report. Funders had no role in the study design, conduct of the study or data analysis, writing of the report, or decision to submit the article for publication.