Patterns of health service use before and after diagnosis of endometriosis: a data linkage prospective cohort study
Authors: Mishra Gita D , Gete Dereje G , Baneshi Mohammad R , Montgomery Grant , Taylor Jessica , Doust Jenny , Abbott Jason 
Published: February 2025

Abstract

STUDY QUESTION
What are the patterns of health service use (HSU) before and after endometriosis diagnosis?

SUMMARY ANSWER
Women with endometriosis had higher rates of visits to general practitioners (GPs), specialists, and diagnostic imaging before and after diagnosis compared to those without the condition; however, after diagnosis, their visits to GPs and specialists other than obstetricians/gynaecologists decreased compared to before, while visits to obstetricians/gynaecologists and use of diagnostic imaging increased.

WHAT IS KNOWN ALREADY
Women with endometriosis have higher rates of healthcare use compared to those without the condition; however, no longitudinal study has examined patterns of HSU over a prolonged period before and after diagnosis.

STUDY DESIGN, SIZE, DURATION
The Australian Longitudinal Study on Women’s Health linked to a national administrative health record. A total of 30 473 women, born in 1973–1978 and 1989–1995, from two cohorts with data collected from 1996 to 2021, as online or postal questionnaires.

PARTICIPANTS/MATERIALS, SETTING, METHODS
Women with endometriosis were identified using the self-report surveys and their administrative health records. A control group of women without endometriosis was randomly selected and age-matched with women with endometriosis. The final sample included 9545 women from the 1973–1978 cohort (1909 cases, 7636 controls) and 7510 from the 1989–1995 cohort (1502 cases, 6008 controls). Women’s HSU was assessed using the Medicare Benefits Schedule database. A random intercept zero-inflated negative binomial model was used to compare outcomes between cases and controls, addressing skewed data, over-dispersion, and excess zeros.

MAIN RESULTS AND THE ROLE OF CHANCE
In both cohorts, women with endometriosis had a higher level of HSU, both before and after diagnosis, compared with those without the condition. For the 1973–1978 cohort, women with endometriosis had a higher rate of visits to GPs before and after diagnosis (adjusted incidence rate ratio: 1.19, 95% CI 1.14, 1.23 and 1.24, 95% CI 1.19, 1.30, respectively), specialists other than obstetricians/gynaecologists (1.50, 95% CI 1.40, 1.61, and 1.36, 95% CI 1.27, 1.46), and for diagnostic imaging (1.15, 95% CI 1.10, 1.21, and 1.20, 95% CI 1.15, 1.26). The average number of these visits remained consistent in the early years, peaked around 3 years before diagnosis, and then partly declined post-diagnosis, to later stabilize at a higher level than those without the condition. Following the diagnosis, women with endometriosis had a higher number of visits to obstetricians/gynaecologists (1.11, 95% CI 1.05, 1.17) than their matched controls, with a marked increase in the first 6 years post-diagnosis, but gradually returned to same levels as the control group. After diagnosis, women with endometriosis had a lower rate of visits to GPs (0.95, 95% CI 0.93, 0.98) and specialists other than obstetricians/gynaecologists (0.88, 95% CI 0.82, 0.93) compared to before their diagnosis, while they had a higher rate of visits to obstetricians/gynaecologists (1.09, 95% CI 1.01, 1.18) and diagnostic imaging (1.07, 95% CI 1.01, 1.14). Similar patterns of HSU were observed in the 1989–1995 cohort, regardless of whether surgically confirmed or clinically suspected cases of endometriosis were used, though the evidence for changes in specific HSU before and after diagnosis was weaker.

LIMITATIONS, REASONS FOR CAUTION
Approximately half of the women with endometriosis were clinically suspected cases without laparoscopic confirmation, which may result in an overestimation of prevalence and introduce the risk of misdiagnosis, potentially influencing clinical management and research findings.

WIDER IMPLICATIONS OF THE FINDINGS
The continued high level of HSU among women with endometriosis, even over a decade after diagnosis, suggests that they have substantially greater healthcare needs than other women. The distinct patterns of the use of healthcare in the years before and after endometriosis diagnosis can support efforts to improve diagnosis, management, and treatment outcomes for patients and to reduce healthcare costs.

STUDY FUNDING/COMPETING INTEREST(S)
The Australian Longitudinal Study on Women’s Health is funded by the Australian Government Department of Health and Aged Care. G.D.M. and G.M. are Australian National Health and Medical Research Council Leadership Fellows (GNT2009577 and GNT1177194). D.G.G. was funded by MRFF EndoAIMM (RFEHP100126). Funding sources had no role in the study design, data analysis, interpretation, or manuscript writing. The authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER
N/A.