Women with endometriosis have decreased health-related quality of life until late fertile age: a population-based cohort analysis at ages 31 and 46 years.

STUDY QUESTION

What is the health-related quality of life (HRQoL) at fertile and late fertile age in women with history of endometriosis?

SUMMARY ANSWER

Women with endometriosis have lower HRQoL until late fertile age and depression, infertility, pain, and poor general health seem to contribute to this impairment, whereas BMI, education, smoking, parity, current use of contraceptives, and contact to tertiary care have positive association with HRQoL in this population.

WHAT IS KNOWN ALREADY

Women with endometriosis are known to have decreased HRQoL at fertile age, however, studies concerning late fertile age and beyond are lacking.

STUDY DESIGN, SIZE, DURATION: This study utilized Northern Finland Birth Cohort 1966, which is a unique, population-based dataset comprising all expected births in 1966. The present study included data from two collection time points, at ages 31 (fertile age) and 46 years (late fertile age), including both questionnaire and clinical measures. The endometriosis diagnosis was obtained from self-reported questionnaires as well as through a data linkage to the Finnish Institute for Health and Welfare Care Register for Health Care (CRHC) to obtain International Classification of Diseases (ICD) code data from years 1972-2020.

PARTICIPANTS/MATERIALS, SETTING, METHODS: Altogether, 419 women with and 3279 women without endometriosis were identified. The diagnosis for endometriosis was based on either CRHC-derived ICD data (n = 298) and/or self-reported history of endometriosis diagnosed by a physician (n = 283). HRQoL was assessed with the 15D instrument, which is a generic, comprehensive, and standardized tool to measure HRQoL. The 15D score and the dimensional level values range from 0 to 1, score 1 indicating full health and 0 indicating death. The questionnaire was completed by 252 women with endometriosis at 31 years and 302 women at age 46 years. The corresponding numbers in the reference group were 2057 and 2626, respectively. Several confounding factors were also considered.

MAIN RESULTS AND THE ROLE OF CHANCE

In women with endometriosis, HRQoL was lower both at fertile and at late fertile age when compared with women without endometriosis, yet the total score did not reach clinical significance, set as ±0.015 change in HRQoL total score (age 31 years: 0.944 vs 0.951, P = 0.04; age 46 years: 0.916 vs 0.924, P = 0.03). At age 31 years, the 15D single index scores on 'sleeping', 'depression', and 'distress' were impaired in women with endometriosis, whereas 'sleeping' was impaired at age 46 years in affected women. The HRQoL decreased both in endometriosis and reference groups over time from age 31 to 46 years. In the non-adjusted analysis, women with endometriosis had their HRQoL score in the lowest quartile as often as the women without endometriosis at 31 or 46 years (OR [95% CI] 1.33 [1.00-1.78]); age 46 years (1.28 [0.98-1.66]). However, when the adjusted risk model took into account BMI, education, and smoking, there was a significant risk for lower HRQoL in endometriosis cases at both time points (age 31 years: OR [95% CI] 1.42 [1.06-1.91]; age 46 years: 1.42 [1.06-1.89]) and at age 31 years when parity and contraceptive use were considered in the model (OR [95% CI] 1.40 [1.03-1.91]). Depression, infertility, pain, and poor general health seemed to contribute to impaired HRQoL. Moreover, in the subgroup analysis, women with self-reported endometriosis had a higher risk for lower HRQoL scores at fertile and late fertile age than women with a hospital-based disease code when compared with reference population.

LIMITATIONS, REASONS FOR CAUTION: Given the well-known lack of awareness and diagnostic delay in endometriosis, there may be undiagnosed cases of endometriosis among the reference group that may have led to underestimations of the differences between the study groups. Moreover, we were not able to identify the type of intervention during hospitalization in the present dataset. Also, the ethnicity of this study population is rather homogenous and thus may not be generalized in other ethnicities.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first population-based data to show women with endometriosis presenting low HRQoL at fertile and even at late fertile age, although with only mild decrease compared to non-endometriosis cases. HRQoL-items like 'sleeping', 'depression', and 'distress' were affected giving the idea that these items should be targeted in patient care, noting that depression, infertility, pain, and poor general health contributed to lower HRQoL. On the other hand, supporting fertility, hormonal treatments and access to tertiary care may offer solutions to improve HRQoL in women suffering from endometriosis.

STUDY FUNDING/COMPETING INTEREST(S): The study has been funded with grants received from the Finnish Society of Obstetrics and Gynaecology (S.V.), University of Oulu (S.V.), Paulo Foundation (S.V.), Gedeon Richter (S.V.), Sigrid Jusélius Foundation (T.T.P.), and Oulu University Hospital (T.T.P., H.-R.R., L.M.-P.). The NFBC1966 31-year follow-up received financial support from the University of Oulu Grant no. 65354, Oulu University Hospital Grant no. 2/97 and 8/97, Ministry of Health and Social Affairs Grant no. 23/251/97, 160/97 and 190/97, the National Institute for Health and Welfare, Helsinki Grant no. 54121 and the Regional Institute of Occupational Health, Oulu, Finland Grant no. 50621 and 54231. The NFBC1966 46-year follow-up received financial support from University of Oulu Grant no. 24000692, Oulu University Hospital Grant no. 24301140 and European Regional Development Fund (ERDF) Grant no. 539/2010 A31592. Authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.