Severe mental illness and non-specific abdominal pain in the emergency department: a multi-institutional database study

Abdominal pain frequently leads to emergency department (ED) visits, with non-specific abdominal pain (NSAP) being a common diagnosis. Patients with severe mental illness (SMI) face higher risks due to atypical disease presentations and elevated comorbidity rates. Studies show that patients with both SMI and NSAP have increased ED revisit rates and delayed diagnoses. This study examines ED management, unscheduled ED revisit rates, and short-term adverse outcomes in patients with both SMI and NSAP using data from the Chang Gung Research Database from 01 January 2007, to 31 December 2017. Diagnoses were confirmed through the International Classification of Diseases (ICD) codes and medical records, with a 1:3 matching ratio for the non-SMI group using a Greedy algorithm. The outcomes assessed were ED management, 72-hour unscheduled ED revisits, and 7-day adverse events. From seven hospitals, 233,671 patients were initially included over 11 years; 98,722 were excluded, leaving 134,949 for analysis. The SMI group showed higher comorbidity rates, more frequent 72-hour unscheduled ED revisits, and greater use of analgesics but were less likely to receive laboratory tests or CT scans. Non-SMI patients were more likely to be admitted to the hospital and receive invasive procedures within 7 days after index discharge. There were no significant differences in intensive care unit (ICU) admissions, abdominal surgery, or in- hospital mortality between the groups. This study indicates that while patients with SMI and NSAP have higher 72-hour ED revisit rates, they do not experience higher shortterm adverse outcomes. Although NSAP is generally safe for all patients, the higher unscheduled revisit rate highlights the need for tailored healthcare interventions to reduce health disparities in this vulnerable group. Future efforts should focus on strategies to improve healthcare for individuals with SMI and NSAP.