Duration of untreated illness in eating disorders: a comprehensive systematic review and meta-regression

Abstract

Abstract Introduction Eating disorders (EDs) substantially impair physical health, psychological well-being, and social functioning. Shorter untreated illness duration has been proposed to be associated with better outcomes, though evidence for this relationship remains mixed. Nonetheless, delays in accessing treatment remain common and contribute to prolonged suffering and risk of lasting harm. This study aimed to estimate the duration of untreated eating disorder (DUED) and examine potential moderators. Methods A PRISMA 2020-compliant systematic review and meta-analysis was conducted. Searches were performed from inception to March 2026 in PubMed, Embase, PsycINFO, and CINAHL. Random-effects models were used to estimate pooled DUED of available studies, with subgroup and meta-regression analyses to explore moderators. Study quality and risk of bias were assessed using National Institutes of Health (NIH) tools. Results Of 2,776 records identified, 29 studies (n = 17,433) were included. The pooled DUED of available studies was 21.9 months (95% CI 18.0–25.8), with substantial heterogeneity (I² = 99.7%). In subgroup analyses, DUED was longer in bulimia nervosa than anorexia nervosa (41.5 vs. 19.9 months). Meta-regression identified mean age as a significant moderator (β = 1.91, 95% CI 1.1 to 2.7, p < 0.001), indicating longer delays in older individuals. DUED also differed across country, continent, age group, and study design, while decade subgroup estimates were lower in studies from the 2020s than the 2010s. Conclusion Individuals with EDs experience substantial delays before accessing treatment, with untreated illness exceeding 20 months on average. Older age was associated with longer DUED, suggesting potential gaps in detection and help-seeking among adults. DUED varies across demographic, geographic and methodological factors. While decreasing DUED over time is encouraging, these findings highlight the need for earlier identification and streamlined care pathways to reduce delays and improve outcomes in people with ED.