Healthcare Cost and Utilization Project (HCUP) Statistical Briefs [Internet].

Highlights

• In the past decade, average inflation-adjusted hospital costs for all discharges combined grew by 2 percent annually, while total hospital discharges and average length of a hospital stay remained relatively stable.
• Average hospital costs (in 2013 dollars) increased from $9,100 in 2003 to $10,600 in 2011, and they are projected to be $11,000 in 2013. Total hospital discharges remained relatively stable at 37 to 38 million discharges per year. The average length of a hospital stay remained relatively stable at 4.7 to 4.8 days, and it is projected to be 4.6 days in 2013.
• Across five general types of hospital service lines, average hospital costs grew by more than 2 percent on average per year for three: surgical, injury, and maternal and neonatal hospitalizations. Discharge volume changed relatively little for all hospital service lines except mental health, which grew by more than 1 percent on average per year. Average length of stay decreased slightly for all hospital service lines except maternal and neonatal, which had slight growth.
• The most costly hospital stays were for surgery and injury (projected at $22,500 and $15,100, respectively, in 2013). Discharge volume was highest for medical stays, projected at 17.8 million in 2013 (about half of all stays). Length of stay was longest for mental health and shortest for maternal and neonatal (projected at 6.7 and 3.2 days, respectively, in 2013).

Average hospital costs, total discharges, and average length of stay by hospital service line, 2003–2013

Table 1 summarizes the average hospital costs, total discharges, and average length of stay for all inpatient hospitalizations and hospitalizations for five component hospital service lines in 2003 and 2011 (actual values) and for 2013 (projected values). The average annual percentage change from 2003 to 2011 (actual change) and from 2011 to 2013 (projected change) is presented.

Table 1

Average hospital costs (inflation-adjusted), total discharges, and average length of stay by hospital service line, 2003–2013.

• Average hospital costs increased by 2 percent per year between 2003 and 2011, and they are projected to continue to increase at about this same rate through 2013.
  Average hospital costs, which were adjusted for inflation, increased by an average of 2.0 percent per year between 2003 and 2011. These costs are projected to continue to increase at about this same rate per year (1.9 percent) through 2013. In 2003, average hospital costs (in 2013 dollars) were $9,100, and they are projected to reach $11,000 per stay in 2013.
  Average hospital costs grew for all hospital service lines. Between 2003 and 2011, hospital costs grew by more than 2 percent per year for three service lines: maternal and neonatal (2.5 percent), surgical (2.4 percent), and injury (2.2 percent).
• Total hospital discharges remained relatively stable between 2003 and 2011, and they are projected to decrease slightly through 2013.
  The overall number of hospital discharges changed minimally at 0.1 percent average annual growth between 2003 and 2011. Discharges are projected to decrease by an average of 0.5 percent per year from 2011 through 2013. There were 37.4 million total hospital discharges in 2003, and this is projected to be virtually unchanged in 2013 at 37.3 million discharges.
  Four of the five hospital service lines experienced relatively little change in hospital discharges between 2003 and 2011, ranging from −0.7 percent average change per year for maternal and neonatal discharges to 0.6 percent average change per year for medical discharges. Only mental health discharges experienced noteworthy growth at 1.9 percent per year, which is projected to continue at 1.4 percent growth per year through 2013. The other service lines are expected to experience a slight to moderate decrease in discharges.
• Average length of stay remained relatively stable between 2003 and 2011, and it is projected to decrease somewhat through 2013.
  The average length of a hospital stay changed minimally at −0.1 percent average change per year from 2003 through 2011. Length of stay is projected to decrease by an average of 0.8 percent per year from 2011 through 2013. In 2003, the average length of a hospital stay was 4.8 days; this is projected to be 4.6 days in 2013.
  Four of the five hospital service lines—medical, surgical, injury, and mental health—experienced a slight decrease in length of stay between 2003 and 2011, which is projected to continue or decrease further through 2013. Only the maternal and neonatal service line experienced an increase in the length of stay, from 3.0 days in 2003 to 3.2 days in 2011 (0.6 percent annual growth); the average length of stay is also projected at 3.2 days in 2013 (0.4 percent annual growth).

Figures 1–3 show the 2003–2013 actual and projected trend in average hospital costs (Figure 1), total discharges (Figure 2), and average length of stay (Figure 3) for the five hospital service lines.

Figure 1

Average hospital costs (inflation-adjusted) by service line, quarterly values 2003–2013. Note: Inflation-adjusted costs are presented in fourth quarter 2013 dollars. Source: Agency for Healthcare Research and Quality (AHRQ), Center for Delivery,(more...)

Figure 2

Total discharges by service line, quarterly values 2003–2013. Source: Agency for Healthcare Research and Quality (AHRQ), Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project (HCUP), State Inpatient Databases(more...)

Figure 3

Average length of stay by service line, quarterly values 2003–2013. Source: Agency for Healthcare Research and Quality (AHRQ), Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project (HCUP), State Inpatient Databases(more...)

• Average hospital costs were highest for the surgical service line and lowest for the maternal and neonatal service line.
  Average hospital costs, adjusted for inflation, differed substantially by hospital service line. The surgical service line had the highest costs (in 2013 dollars) at $17,600 in 2003, which are projected to be $22,500 in 2013. The injury service line had the second-highest hospital costs overall at $12,100 in 2003, which are projected to be $15,100 in 2013. The other three service lines had average hospital costs below $10,000: medical ($9,400 projected in 2013), mental health ($6,600 projected in 2013), and maternal and neonatal ($4,500 projected in 2013).
• Total discharges were highest for the medical service line and lowest for the injury and mental health service lines.
  The medical service line had the highest number of hospital discharges overall. Although there was some seasonal data fluctuation, it averaged around 16 to 17 million total discharges per year (4 to 4.5 million discharges per quarter). The surgical and maternal and neonatal service lines each had about 8 million total discharges per year (around 2 million discharges per quarter). The mental health and injury service lines had the fewest discharges at approximately 1.8 to 2 million discharges per year (400,000 to 450,000 discharges per quarter).
• Average length of stay was longest for the mental health service line and shortest for the maternal and neonatal service line.
  The average length of a hospital stay was longest for the mental health service line at 7.4 days in 2003, which is projected to continue to be the longest at 6.7 days in 2013. The surgical service line had a length of stay of 5.8 days in 2003, which is projected to be 5.5 days in 2013. The medical and injury service lines had similar lengths of stay around 4.9 to 5.0 days in 2003, which are projected to be about 4.6 to 4.7 days in 2013. The maternal and neonatal service line had the shortest length of stay at around 3.0 days in 2003, which is projected to continue to be the shortest at 3.2 days in 2013.

Case definition

Coding criteria for the five hospital service lines are provided inTable 2 and are based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes, Clinical Classifications Software (CCS) categories, and diagnosis-related groups (DRGs) (see definitions below). Each discharge was assigned to a single hospital service line hierarchically, based on the following order: maternal and neonatal, mental health, injury, surgical, and medical.

Table 2

Coding criteria for the five hospital service lines analyzed in this research.

Diagnoses, ICD-9-CM Clinical Classifications Software (CCS), and Diagnosis-Related Groups (DRGs)

Theprincipal 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 develop during the stay.All-listed diagnoses include the principal diagnosis plus these additional secondary conditions.

ICD-9-CM assigns numeric codes to diagnoses. There are approximately 14,000 ICD-9-CM diagnosis codes.

CCS categorizes ICD-9-CM diagnoses into a manageable number of clinically meaningful categories.⁶ This “clinical grouper” makes it easier to quickly understand patterns of diagnoses. CCS categories identified as “Other” typically are not reported; these categories include miscellaneous, otherwise unclassifiable diagnoses that may be difficult to interpret as a group.

DRGs comprise a patient classification system that categorizes patients into groups that are clinically coherent and homogeneous with respect to resource use. DRGs group patients according to diagnosis, type of treatment (procedures), age, and other relevant criteria. Each hospital stay has one assigned DRG.

Average annual percentage change

Average annual percentage change is calculated using the following formula:

Types of hospitals included in HCUP

HCUP is based on data from community hospitals, which are defined as short-term, non-Federal, general, and other hospitals, excluding hospital units of other institutions (e.g., prisons). HCUP data include obstetrics and gynecology, otolaryngology, orthopedic, cancer, pediatric, public, and academic medical hospitals. Excluded are long-term care, rehabilitation, psychiatric, and alcoholism and chemical dependency hospitals. However, if a patient received long-term care, rehabilitation, or treatment for psychiatric or chemical dependency conditions in a community hospital, the discharge record for that stay will be included in the State Inpatient Databases (SID).

Unit of analysis

The unit of analysis is the hospital discharge (i.e., the hospital stay), not a person or patient. This means that a person who is admitted to the hospital multiple times in one year will be counted each time as a separate “discharge” from the hospital.

Costs and charges

Total hospital charges were converted to costs using HCUP Cost-to-Charge Ratios (CCRs) based on hospital accounting reports from the Centers for Medicare & Medicaid Services (CMS).⁷Costs will reflect the actual expenses incurred in the production of hospital services, such as wages, supplies, and utility costs;charges represent the amount a hospital billed for the case. For each hospital, a hospital-specific CCR is used. The CCRs are at the hospital level and are not sensitive to possible differences by hospital service line. Hospital charges reflect the amount the hospital billed for the entire hospital stay and do not include professional (physician) fees. For the purposes of this Statistical Brief, costs are reported to the nearest hundred.

Quarterly cost data from the HCUP Projections⁸ were weighted to produce annual costs. Quarterly and annual costs were inflation adjusted using the Gross Domestic Product (GDP) from the U.S. Department of Commerce, Bureau of Economic Analysis (BEA), with either the 2013 annual (Table 1) or 2013 fourth quarterly value (Figure 1) as the index base.⁹ That is, all costs are expressed in 2013 dollars.