Lifetime prevalence and clinical correlates of nonsuicidal self-injury in youth inpatients with eating disorders: a retrospective chart review

BACKGROUND: Youths with eating disorders (EDs) engaging in nonsuicidal self-injury (NSSI) are at higher suicide risk because EDs and NSSI are associated with suicidality. However, epidemiologic data on NSSI lacks in the vulnerable group of youth ED inpatients. METHODS: This retrospective chart review included patients up to 18 years of age with an ICD-10 diagnosis of anorexia nervosa, restricting type (AN-R), anorexia nervosa, binge-purge type (AN-BP), and bulimia nervosa (BN), treated at the child and adolescent inpatient department of the University Hospital in Berlin, Germany, between 1990 and 2015. Across and within ED subgroups, lifetime NSSI prevalence, methods of self-harm, and clinical correlates were evaluated. Independent correlations of demographic and clinical factors with NSSI were identified via multivariable regression models. RESULTS: Of 382 inpatients (median = 15.6 (range = 9–18) years, females = 97.1%), 21.5% reported lifetime NSSI, consisting of cutting = 86.6%, scratching = 12.2%, and hitting = 8.5%. NSSI was more frequent in BN (47.6%) and AN-BP (39.3%) than AN-R (8.3%) (Φ = 0.43). Across ED subgroups, NSSI was associated with a higher prevalence of psychiatric comorbidities (AN-R: Φ = 0.55; AN-BP: Φ = 0.69; BN: Φ = 0.78), suicidal ideation (AN-R: Φ = 0.30; AN-BP: Φ = 0.38; BN: Φ = 0.29), and psychiatric medication use (AN-R: Φ = 0.23; AN-BP: Φ = 0.64; BN: Φ = 0.60). In multivariable regression analyses, NSSI was independently associated with a higher prevalence of psychiatric comorbidities (AN-R: OR = 2.93 [1.42, 6.04]; AN-BP: OR = 2.67 [1.13, 6.31]; BN: OR = 3.75 [1.71, 8.23]). Additionally, independent correlates with NSSI in AN-R included a higher prevalence of suicidal ideation (OR = 0.21 [0.72, 0.64]) and less weekly weight gain (OR = 0.03 [0.02, 0.43]), while in BN, NSSI was correlated with longer inpatient treatment duration (OR = 1.01 [1.00, 1.02]). CONCLUSIONS: There is a high lifetime prevalence of NSSI among youth with AN and BN requiring inpatient treatment, especially those with binge-purge behaviors. Treatment programs must be tailored to address psychiatric comorbidities and suicidality to improve patient care and suicide prevention. Trial registration: This study was not considered a clinical trial but a retrospective chart review based on routinely assessed clinical parameters. The study includes data from human participants, however: (1) no intervention and no prospective assignment to interventions were performed, and (2) no evaluation of an intervention on participants was accomplished. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13034-022-00446-1.