A US population-based study of uterine fibroid diagnosis incidence, trends, and prevalence: 2005 through 2014

Background: Despite considerable public health burden, uterine fibroid population-based incidence estimates are few. Secular trends over time are even more limited.

Objective: We sought to evaluate the incidence, 10-year secular trends, and prevalence of uterine fibroid diagnoses and describe the proportion of symptomatic women.

Study design: We performed a retrospective population-based cohort study of women, aged 18-65 years, enrolled 2005 through 2014 in Kaiser Permanente Washington. Uterine fibroid diagnoses identified by International Classification of Diseases, Ninth Revision codes and potential covariates were extracted from computerized databases. Women with prior hysterectomy and, for incidence estimates, women with prior fibroid diagnoses were excluded. Linear trends in incidence rates over the 10-year study period were evaluated using Poisson regression models. Rates and trend tests were examined for all women, by age groups, and by race/ethnicity.

Results: Associated International Classification of Diseases, Ninth Revision symptom-related codes were observed in 90% of incident cases. Incidence rates for fibroid diagnoses were highest for the age group 45-49 years, 240.3 per 10,000 woman-years in 2014, and for black women across all years. Overall age-adjusted estimated incidence rates declined during the 10-year study interval, from 139.4 per 10,000 woman-years in 2005 to 101.4 in 2014 (P value trend .0008). Overall prevalence in 2014 was 9.6%, and was highest among women aged 50-54 years (15.9%). Black women had higher prevalence (18.5%) than other racial/ethnic groups.

Conclusion: We found a decreasing trend of new uterine fibroid diagnoses among predominantly symptomatic women ages 18-65 years in a recent 10-year interval. This finding was due, perhaps in part, to secular trends of decreasing hysterectomies. Nonetheless, uterine fibroids remain a common health burden, with a prevalence of nearly 10%. Rates are disproportionately high and occur at younger ages for black women, and possibly for other non-white racial/ethnic groups. These findings are of concern, as current available long-term medical therapies remain limited.