Taking a Deeper Dive Into OSFED Subtypes: A Meta-Analysis and Systematic Review

Objective: To compare all other specified feeding or eating disorders (OSFED) groups (atypical anorexia nervosa [AN], purging disorder [PD], night eating syndrome [NES], subthreshold bulimia nervosa [sub-BN], and subthreshold binge-eating disorder [sub-BED]) to threshold eating disorders (EDs [AN, BN, and BED]) and control groups (CGs) on measures of eating and general psychopathology.

Method: We conducted a comprehensive search in PsycINFO, Medline, Embase, and CINAHL on all published studies from January 2013 to February 2024 using DSM-5 diagnostic criteria via clinical interviews or well-established diagnostic tools. We also undertook a quality appraisal using an adapted version of the Downs and Black criteria and registered the review with PROSPERO (ID: CRD42022314495).

Results: Overall, our meta-analyses (n = 33 eligible studies) indicated that the combined OSFED and several specific OSFED subtypes displayed comparable levels of eating psychopathology to full-threshold EDs. Our systematic review (n = 33 eligible studies) found individuals with OSFED to have comparable levels of eating and general psychopathology to full-threshold EDs, but higher levels of eating and general psychopathology than CGs. These findings were specifically attributed to atypical AN and NES. There was a lack of evidence available for sub-BN and sub-BED. Studies mainly met the quality appraisal criteria. The main limitations identified in the included studies were insufficient reporting of their statistical power (78%) and no adjusting for potential confounding factors (67%).

Discussion: Findings support the conceptualization of atypical AN, and NES as clinically significant EDs with similar severity to full-threshold EDs.