Psychosocial Assessment of Self-Harm Patients and Risk of Repeat Presentation: An Instrumental Variable Analysis Using Time of Hospital Presentation

• Published in: PloS one Vol. 11; no. 2; p. e0149713
• Main Authors: Carroll, Robert, Metcalfe, Chris, Steeg, Sarah, Davies, Neil M., Cooper, Jayne, Kapur, Nav, Gunnell, David
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 26.02.2016; Public Library of Science (PLoS)
• Subjects: Adult; Bias; Cohort Studies; Collaboration; Confidence intervals; Control equipment; Data collection; Data processing; Demographic aspects; Diagnosis; Emergency medical services; Epidemiology; Estimates; Female; Hospitalization - statistics & numerical data; Hospitals; Humans; Indication; Likelihood Functions; Male; Medical research; Medicine; Medicine and Health Sciences; Mental health care; Patients; People and Places; Physical Sciences; Poisoning; Population studies; Psychometrics; Regression Analysis; Research and Analysis Methods; Risk; Risk analysis; Risk assessment; Risk reduction; Self destructive behavior; Self injurious behavior; Self-Injurious Behavior - psychology; Self-Injurious Behavior - therapy; Statistical analysis; Studies; Time Factors; Time of use; Trends; United Kingdom; United Kingdom > UK
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0149713

Clinical guidelines have recommended psychosocial assessment of self-harm patients for years, yet estimates of its impact on the risk of repeat self-harm vary. Assessing the association of psychosocial assessment with risk of repeat self-harm is challenging due to the effects of confounding by indication. We analysed data from a cohort study of 15,113 patients presenting to the emergency departments of three UK hospitals to investigate the association of psychosocial assessment with risk of repeat hospital presentation for self-harm. Time of day of hospital presentation was used as an instrument for psychosocial assessment, attempting to control for confounding by indication. Conventional regression analysis suggested psychosocial assessment was not associated with risk of repeat self-harm within 12 months (Risk Difference (RD) 0.00 95% confidence interval (95%CI) -0.01 to 0.02). In contrast, IV analysis suggested risk of repeat self-harm was reduced by 18% (RD -0.18, 95%CI -0.32 to -0.03) in those patients receiving a psychosocial assessment. However, the instrument of time of day did not remove all potential effects of confounding by indication, suggesting the IV effect estimate may be biased. We found that psychosocial assessments reduce risk of repeat self-harm. This is in-line with other non-randomised studies based on populations in which allocation to assessment was less subject to confounding by indication. However, as our instrument did not fully balance important confounders across time of day, the IV effect estimate should be interpreted with caution.