General findings

In 2007, of the 95 million visits made to the emergency department (ED) by adults in the U.S., 12.0 million (12.5 percent) were related to MHSA (table 1)—4.1 million of which had mental health or substance abuse conditions listed as a primary diagnosis. Nearly 41 percent (4.8 million visits) of these MHSA-related ED visits resulted in hospital admission—an admission rate that is over two and a half times that for ED visits related to other conditions (figure 1).

Table 1

Characteristics of ED Visits Related to Mental Health and Substance Abuse Conditions among Adults, 2007.

Figure 1

MHSA-related ED visits were three to four times more likely to result in hospitalization than other types of ED visits, 2007. Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Emergency Department (more...)

Table 1 shows that the majority of MHSA-related ED visits were for women (53.9 percent). The largest percentage of MHSA-related ED visits (46.6 percent) were for younger adults ages 18 to 44 years, followed by 45 to 64 year olds (34.5 percent). Adults 65 years and older accounted for nearly one in five (18.9 percent) MHSA-related ED visits. Compared with ED visits for other conditions, those related to MHSA were more likely to be for 45 to 64 year olds (34.5 percent versus 25.8 percent) and less likely to be for adults 18 to 44 years (46.6 percent versus 52.4 percent) and 65 years and older (18.9 percent versus 21.8 percent).

Medicare, healthcare insurance for those 65 years and older or those on Social Security Disability Insurance, was billed more frequently for MHSA-related ED visits (30.1 percent), followed by private insurance (25.7 percent), uninsured (20.6 percent), and Medicaid (19.8 percent). In contrast, private insurance was billed more frequently for most other types of ED visits (34.5 percent), followed by Medicare (24.7 percent), uninsured (20.6 percent), and Medicaid (14.9 percent).

Types of MHSA-related ED visits

Table 1 shows the distribution of MHSA-related ED visits, including those related to only mental health conditions (i.e., not substance abuse condition), those related to only substance abuse conditions (i.e., not mental health conditions), and those related to co-occurring MHSA conditions. Over 7.6 million ED visits related to mental health conditions only, accounting for 63.7 percent of all MHSA-related ED visits. Nearly 3.0 million ED visits related to substance abuse conditions only, accounting for 24.4 percent of all MHSA-related ED visits. Over 1.4 million visits related to co-occurring MHSA conditions, accounting for 11.9 percent of MHSA-related ED visits.

Patient and payer characteristics of types of MHSA-related ED visits

Table 1 shows that ED visits related to mental health conditions were more likely to be for women (65.4 percent), while ED visits related to substance abuse conditions (29.3 percent) and co-occurring MHSA conditions (43.0 percent) were less likely to be for women and more likely to be for men. Regardless of the type of condition, MHSA-related ED visits were more likely to be for younger adults 18 to 44 years.

ED visits related to co-occurring MHSA conditions were disproportionately more likely to be for 18–44 year olds—58.8 percent of ED visits for co-occurring MHSA conditions were for 18–44 year olds (versus 42.7 percent for mental conditions only and 50.7 percent for substance abuse conditions only). ED visits related to mental health conditions were disproportionately more likely to be for the oldest adults 65 years and older (25.3 versus 9.1 and 5.2 percent related to substance abuse conditions and co-occurring MHSA conditions, respectively).

Medicare was billed more frequently for mental health-related ED visits (37.2 percent), followed by private insurance (27.5 percent) and Medicaid (18.3 percent). Fewer mental health-related ED visits were billed as uninsured (13.8 percent). In contrast, the largest percentage of substance abuse-related ED visits was billed as uninsured (35.6 percent). Private insurance accounted for 22.2 percent of substance abuse-related ED visits, followed by Medicaid (20.7 percent) and Medicare (16.3 percent). Nearly one-fourth of ED visits for co-occurring MHSA conditions were billed as uninsured (26.3 percent) or to Medicaid (25.7 percent) or private insurance (23.4 percent). Medicare accounted for 20.3 percent of ED visits related to co-occurring MHSA conditions.

Admission status for MHSA-related ED visits, by age and expected payer

Figure 1 highlights that ED visits related to co-occurring MHSA conditions were the most likely to result in hospital admission (57.1 percent), followed by visits related to mental health conditions (39.3 percent), and substance abuse conditions (36.6 percent). Figures 2 and 3 show that visits related to co-occurring MHSA conditions were more likely to result in hospital admission than either visits related to mental health only or substance abuse only within age and payer groups.

Figure 2

Admission rates for MHSA-related ED visits increased with age, 2007. Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Emergency Department Sample, 2007

Figure 3

Uninsured MHSA-related ED visits were two to four times less likely to result in hospitalization than visits billed to other payers, 2007. Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Emergency (more...)

Admission rates increased with age, regardless of the type of MHSA-related ED visits (figure 2). ED visits for adults 18 to 44 years with mental health conditions were the least likely to result in hospital admission (20.3 percent), while ED visits for adults 65 years and older with co-occurring MHSA conditions were the most likely to result in admission (82.0 percent).

Hospital admission rates varied by expected payer (figure 3). ED visits billed to Medicare were more likely to result in admission, regardless of the type of MHSA condition (58.9, 58.0, and 70.8 percent, related to mental health only, substance abuse only, and co-occurring MHSA, respectively). ED visits billed as uninsured were the least likely to result in hospital admission, regardless of the type of MHSA condition (15.1, 23.8, and 41.3 percent related to mental health only, substance abuse only and co-occurring MHSA, respectively).

Number and distribution of ED visits for the most frequent all-listed MHSA conditions, by age and expected payer

As shown in table 2, the most common all-listed reason for a MHSA-related ED visit was mood disorder (42.7 percent of MHSA-related ED visits), followed by anxiety disorders (26.1 percent), alcohol disorders (22.9 percent), drug disorders (17.6 percent), schizophrenia and other psychoses (9.9 percent), and intentional self-harm (6.6 percent). The top five conditions accounted for 96.0 percent of all MHSA-related cases in the ED, taking into account that there may be multiple diagnoses on an ED record. Some variation was noted by age and expected payer. For example, among adults 65 years and older, mood disorders accounted for over half of the ED visits (52.0 percent) followed by anxiety disorders (28.8 percent), and schizophrenia and other psychoses (11.4 percent). Although mood disorders were the most frequent condition for all age groups and most payers, alcohol-related conditions were the most frequent condition among the uninsured.

Table 2

Most Common All-Listed MHSA Conditions Seen During an ED Visit, 2007.

Figure 4 shows the age distribution for specific MHSA-related ED visits by condition. ED visits for intentional self-harm (69.0 percent) and drug abuse conditions (63.1 percent) were disproportionately more likely to be for young adults 18–44 years old—accounting for almost 500,000 ED visits and over 1.3 million ED visits in 2007, respectively.

Figure 4

The youngest adults disproportionately accounted for ED visits related to intentional self-harm and drug abuse conditions, 2007. Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Emergency Department (more...)

Figure 5 shows that the payer distribution for each of the MHSA condition specific ED visits varied considerably. For example, ED visits related to mood disorders and those related to schizophrenia and other psychoses were disproportionately more likely to be billed to Medicare (36.6 and 47.4 percent, respectively). ED visits related to drug abuse, alcohol abuse, and intentional self-harm were more frequently billed as uninsured than any other payer (33.3, 31.9, and 29.3 percent, respectively).

Figure 5

Expected payer was associated with specific MHSA-related ED visits, 2007. Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project, Nationwide Emergency Department Sample, 2007; based on all-listed diagnoses. Missing (more...)

Diagnoses, ICD-9-CM, and Clinical Classifications Software (CCS)

The principal diagnosis is that condition established after study to be chiefly responsible for the patient’s admission to the hospital. Secondary diagnoses are concomitant conditions that coexist at the time of admission or that develop during the stay. All-listed diagnoses include the principal diagnosis plus these additional secondary conditions.

ICD-9-CM is the International Classification of Diseases, Ninth Revision, Clinical Modification, which assigns numeric codes to diagnoses. There are about 13,600 ICD-9-CM diagnosis codes.

CCS categorizes ICD-9-CM diagnoses and procedures into clinically meaningful categories.⁶ This “clinical grouper” makes it easier to quickly understand patterns of diagnoses and procedures. Mental health conditions include CCS 650–659, 662, and 670. Substance abuse conditions include CCS 661 and 662.

Case definition

All-listed CCS diagnosis and external cause of injury codes used to identify mental health and substance abuse cases included:

650.

Adjustment disorders

651.

Anxiety disorders

652.

Attention-deficit, conduct, and disruptive behavior disorders

655.

Disorders usually diagnosed in infancy, childhood, or adolescence including pervasive development disorders, tic disorders, and elimination disorders

656.

Impulse control disorders, not elsewhere classified

657.

Mood disorders

658.

Personality disorders

659.

Schizophrenia and other psychotic disorders

660.

Alcohol-related disorders

661.

Drug-related disorders

662.

Intentional self-harm/suicide and intentional self-inflicted injury

670.

Miscellaneous disorders, including eating disorders, mental disorders in pregnancy, dissociative disorders, factitious disorders, sleep disorders, and somatoform disorders

Although dementia (CCS=653) and intellectual disability/developmental disorders (CCS=654) are listed in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, these diagnoses, which are frequently characterized by the development of multiple cognitive impairments related to medical conditions, frequently require more medical than psychiatric treatment and thus are excluded from the analysis.

Treat-and-release ED visits

Treat-and-release ED visits were those ED visits in which patients are treated and released from that ED (i.e., they are not admitted to that specific hospital). While the majority of treat-an-release patients (92.2%) were discharged home, some were transferred to another acute care facility (1.5%), left against medical advice (1.7%), went to another type of long-term or intermediate care facility (nursing home or psychiatric treatment facility) (1.6%), referred to home health care (0.5%) or died (0.2%), or discharged alive but the destination is unknown (2.2%).

ED visits resulting in hospital admission

ED visits resulting in a hospital stay included those patients initially seen in the ED and then admitted to the same hospital.

Types of hospitals included in HCUP

HCUP is based on data from community hospitals, defined as short-term, non-Federal, general and other hospitals, excluding hospital units of other institutions (e.g., prisons). HCUP data include OB-GYN, ENT, orthopedic, cancer, pediatric, public, and academic medical hospitals. They exclude long-term care, rehabilitation, psychiatric, and alcoholism and chemical dependency hospitals, but these types of ED visits are included if they are from community hospitals.

Unit of analysis

The unit of analysis is the ED visit, not a person or patient. This means that a person who visits the ED multiple times in one year will be counted each time as a separate ED visit.

Payer

Payer is the primary expected payer for the ED visit. To make coding uniform across all HCUP data sources, payer combines detailed categories into more general groups:

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Medicare includes fee-for-service and managed care. Medicare is a Health Insurance Program for people age 65 or older, some disabled people under age 65 (social security disability insurance), and people of all ages with End-Stage Renal Disease (permanent kidney failure treated with dialysis or a transplant).

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Medicaid includes fee-for-service and managed care Medicaid patients.

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Private insurance includes Blue Cross, commercial carriers, and private HMOs and PPOs.

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Other includes Workers’ Compensation, TRICARE/CHAMPUS, CHAMPVA, Title V, and other government programs.

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Uninsured includes an insurance status of “self-pay” and “no charge.”

When more than one payer is listed for a hospital discharge, the first-listed payer is used.