Mental Health and Substance Use-Related Hospitalizations Among Women of Reproductive Age in Illinois and Wisconsin

Mental health and substance use are growing public health concerns, but established surveillance methods do not measure the burden of these conditions among women of reproductive age. We developed a standardized indicator from administrative data to identify inpatient hospitalizations related to mental health or substance use (MHSU) among women of reproductive age, as well as co-occurrence of mental health and substance use conditions among those hospitalizations.

We used inpatient hospital discharge data from 2012-2014 for women aged 15-44 residing in Illinois and Wisconsin. We identified MHSU-related hospitalizations through the principal International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis and first-listed ICD-9-CM external cause of injury code (E code). We classified hospitalizations as related to 1 of 3 mutually exclusive categories: a mental disorder, a substance use disorder, or an acute MHSU-related event. We defined co-occurrence as the presence of both mental health and substance use codes in any available diagnosis or E-code field.

Of 1 173 758 hospitalizations of women of reproductive age, 150 318 (12.8%) were related to a mental disorder, a substance use disorder, or an acute MHSU-related event, for a rate of 135.6 hospitalizations per 10 000 women. Of MHSU-related hospitalizations, 115 163 (76.6%) were for a principal mental disorder, 22 466 (14.9%) were for a principal substance use disorder, and 12 709 (8.5%) were for an acute MHSU-related event; 42.4% had co-occurring mental health codes and substance use codes on the discharge record.

MHSU-related disorders and events are common causes of hospitalization for women of reproductive age, and nearly half of these hospitalizations involved co-occurring mental health and substance use diagnoses or events. This new indicator may improve public health surveillance by establishing a systematic and comprehensive method to measure the burden of MHSU-related hospitalizations among women of reproductive age.