Incidence and characterization of diagnosed endometriosis in a geographically defined population.

OBJECTIVE: We examined whether widespread use of laparoscopy was accompanied by increased diagnosis of asymptomatic endometriosis, inflated rates of diagnosis, or changes in the clinical spectrum of disease.
DESIGN: Population-based cohort.
SETTING: Olmsted County, Minnesota. PATIENT(S): All participants were women residents, aged > or =15 years. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): We estimated the likelihood that women with a surgical procedure during which endometriosis could be visualized would receive a surgical diagnosis, as well as the proportions of all diagnoses, regardless of setting, that were [1] assigned without surgery, [2] refuted by surgery, [3] surgically confirmed, and [4] asymptomatic. The incidence of diagnosed endometriosis for 1987 to 1999 was compared with published rates for 1970 to 1979. RESULT(S): Of 8,229 women aged > or =15 years with > or =1 surgery during which endometriosis could be visualized, 11.5% received a surgical diagnosis of endometriosis. The incidence of diagnosed endometriosis, regardless of setting, was 1.9 per 1,000 person-years (10% were without relevant surgery, 6% had surgery but no surgical evidence, 85% had surgical evidence); 85% of surgically confirmed diagnoses had presenting symptoms. Using definitions comparable with those in the 1970 to 1979 study, the 1987 to 1999 incidence was 2.46 per 1,000 versus 2.49 per 1,000 for 1970 to 1979; 88% of symptomatic incident diagnoses were surgically confirmed versus 65% for 1970 to 1979. CONCLUSION(S): Widespread use of laparoscopy does not appear to have contributed to dramatically increased rates of endometriosis diagnoses but rather to a smaller proportion of diagnoses being assigned without surgical confirmation.