OBJECTIVES: Recent research suggests mental health disorder prevalence is increasing in the United States (US). Trends of anxiety, depression, and substance use (ADSU)-related inpatient hospitalizations from 2016-2020 were analyzed to better understand the impact of this increase on healthcare resource utilization.

METHODS: A multi-year cross-sectional analysis was conducted using the Healthcare Cost and Utilization Project’s (HCUP) National Inpatient Sample (NIS), a nationally representative sample of the US hospitalized population derived from hospital billing data. Adult (18+) inpatients with an ADSU International Classification of Diseases 10^th version-clinical modification (ICD-10-CM) diagnosis code from 2016-2020 were included. Annual counts, prevalence, and absolute and percentage changes in ASDU-related hospitalizations were calculated by year and for 2016-2020 and weighted to obtain national estimates. Three cohorts were assessed based on the position of the ADSU diagnosis code in the hospitalization claim record: 1) first two, 2) first five, and 3) any position; earlier positioning suggests the diagnosis code was a greater contributing reason for the hospitalization.

RESULTS: Hospitalizations with ADSU diagnosis codes in the first two or first five positions decreased 14% (-285,787) and 8% (-363,409) from 2016-2020, respectively (both p<0.001). However, hospitalization rate changes were <1% from 2016-2020 for both cohorts, with the first two cohort rate hovering around 6-7% and the first five cohort around 16%. When the diagnosis position was expanded to any, there was a 3% increase (+318,384) (p<0.001) in ADSU-related hospitalizations from 2016-2020, reflecting a 5% increase in the hospitalization rate from 38% in 2016 to 43% in 2020. Among the first five cohort, the suicidal ideation code increased 61% (+241,000) from 2016-2020.

CONCLUSIONS: Results indicate ADSU are not key drivers of US hospitalization rate changes. However, the rise in any ADSU and suicidal ideation codes suggest appropriate ADSU management may be needed to avoid future increased healthcare resource burden.