Objective: To determine the value of patient-reported symptoms in diagnosing endometriosis.
Design: A national case-control study.
Setting: Data from the UK General Practice Research Database for years 1992-2001.
Sample: A total of 5540 women aged 15-55 years, diagnosed with endometriosis, each matched to four controls without endometriosis.
Methods: Data were analysed to determine whether specific symptoms were highly indicative of endometriosis. Odds ratios for these symptoms were derived by conditional logistic regression analysis.
Main outcome measures: Symptoms associated with endometriosis.
Results: The prevalence of diagnosed endometriosis was 1.5%. A greater proportion of women with endometriosis had abdominopelvic pain, dysmenorrhoea or menorrhagia (73%) compared with controls (20%). Compared with controls, women with endometriosis had increased risks of abdominopelvic pain (OR 5.2 [95% CI: 4.7-5.7]), dysmenorrhoea (OR 8.1 [95% CI: 7.2-9.3]), menorrhagia (OR 4.0 [95% CI: 3.5-4.5]), subfertility (OR 8.2 [95% CI: 6.9-9.9]), dyspareunia and/or postcoital bleeding (OR 6.8 [95% CI: 5.7-8.2]), and ovarian cysts (OR 7.3 [95% CI: 5.7-9.4]), and of being diagnosed with irritable bowel syndrome (IBS) (OR 1.6 [95% CI: 1.3-1.8]) or pelvic inflammatory disease (OR 3.0 [95% CI: 2.5-3.6]). Women with endometriosis were also found to consult the doctor more frequently than the controls and were twice as likely to have time off work.
Conclusions: Specific symptoms and frequent medical consultation are associated with endometriosis and appear useful in the diagnosis. Endometriosis may coexist with or be misdiagnosed as pelvic inflammatory disease or IBS.