Hospital utilization and costs for adults with and without MCC, 2003–2014

Figure 1 presents trends in the percentage of nonmaternal hospital inpatient stays among adult patients with and without multiple chronic conditions (MCC) for 2003–2012 (actual values) and for 2013 and 2014 (projected values).

Figure 1

Percentage of hospital inpatient stays by presence of multiple chronic conditions, 2003–2014. Abbreviation: MCC, multiple chronic conditions. Note: The denominator used to calculate the percentages was all nonmaternal, adult hospital stays. For (more...)

• The percentage of nonmaternal hospital stays for adults with MCC increased over time and was substantially higher than the percentage of stays for adults without MCC.
  In 2003, 63.5 percent of nonmaternal, adult stays were for patients with MCC, about 1.7 times higher than stays for patients without MCC (36.5 percent). By 2014, the percentage of stays for patients with MCC is projected to be 3.5 times higher than the percentage of stays for patients without MCC (78.1 vs. 22.0 percent).

Figure 2 presents trends in the cost of nonmaternal hospital inpatient stays among adult patients with and without MCC for 2003–2012 (actual values) and for 2013 and 2014 (projected values). All costs are inflation adjusted to 2014 dollars.

Figure 2

Average inflation-adjusted hospital costs by presence of multiple chronic conditions, 2003–2014. Abbreviation: MCC, multiple chronic conditions. Note: Inflation-adjusted costs are presented in 2014 dollars.

• Hospital stays for adults with MCC were consistently more expensive than stays for adults without MCC, and the difference remained stable over time.
  Average inflation-adjusted hospital costs for nonmaternal stays of adults with MCC were approximately $2,000, or 18 percent, higher than for stays of adults without MCC throughout the 2003–2014 time period. Average hospital costs for adults with MCC were about $12,000 in 2003 (in 2014 dollars) and were projected to increase to $14,500 in 2014. Average hospital costs for adults without MCC were about $9,800 in 2003 and were projected to increase to $12,200 in 2014.

Hospital utilization and costs for adults with MCC by patient age, 2003–2014

Figure 3 presents trends in the percentage of nonmaternal hospital inpatient stays among adult patients with MCC by patient age group for 2003–2012 (actual values) and for 2013 and 2014 (projected values).

Figure 3

Percentage of hospital inpatient stays among adults with multiple chronic conditions by patient age, 2003–2014. Note: The denominator used to calculate each age-specific percentage with multiple chronic conditions (MCC) was all nonmaternal, adult (more...)

• The percentage of hospital stays for adults with MCC increased with age and over time for each age group.
  The percentage of nonmaternal hospital stays that were for adults with MCC was lowest among patients aged 18–44 years at 29.6 percent in 2003 and was projected to increase to 45.4 percent in 2014 (a 53.3 percent increase). The percentage of stays that were for adults with MCC was about 1.8 times higher among patients aged 45–64 years than among those aged 18–44 years, at 59.9 percent in 2003 and projected to increase to 76.2 percent in 2014 (a 27.2 percent increase). Finally, the percentage of stays that were for adults with MCC was about 1.3 times higher among patients aged 65 years and older than among those aged 45–64 years (and 2.3 times higher than among those aged 18–44 years), at 81.0 percent in 2003 and projected to increase to 91.3 percent in 2014 (a 12.7 percent increase).

Figure 4 presents trends in the cost of nonmaternal hospital inpatient stays for adults with MCC by patient age group for 2003–2012 (actual values) and for 2013 and 2014 (projected values). All costs are inflation adjusted to 2014 dollars.

Figure 4

Average inflation-adjusted hospital costs among adults with multiple chronic conditions by patient age, 2003–2014. Note: Inflation-adjusted costs are presented in 2014 dollars. Source: Agency for Healthcare Research and Quality (AHRQ), Center (more...)

• Among hospital stays for adults with MCC, patients aged 45 years and older had higher average hospital costs than those aged 18–44 years.
  Average inflation-adjusted costs for nonmaternal hospital stays of adults with MCC were more than $2,000 higher for patients in the two older age groups (45–64 years and 65 years and older) than those in the youngest age group (18–44 years) across the entire 2003–2014 time period. Average hospital costs for patients aged 45–64 years with MCC were $12,700 in 2003 (in 2014 dollars) and were projected to increase to $15,300 in 2014. Average hospital costs for patients aged 65 years and older with MCC were $12,100 in 2003 and were projected to increase to $14,400 in 2014. Average hospital costs for patients aged 18–44 years with MCC were $9,700 in 2003 and were projected to increase to $12,100 in 2014.

Hospital utilization and costs for adults with MCC by patient age and sex, 2003–2014

Table 1 presents the percentage of nonmaternal hospital stays and average hospital costs among adult patients with MCC by patient age group (as presented in Figures 3 and 4) and by patient sex and age group in 2003 and 2012 (actual values) and in 2014 (projected values). The average annual percentage change from 2003 to 2012 (actual change) and from 2012 to 2014 (projected change) is provided.

Table 1

Percentage of hospital stays and inflation-adjusted average hospital costs among adults with multiple chronic conditions by patient age and sex, 2003–2014.

• Growth in the percentage of hospital stays among adults with MCC has slowed in recent years, and this slower rate of growth is projected to continue through 2014.
  The percentage of nonmaternal hospital stays among adult patients with MCC increased by an average of 2.0 percent per year between 2003 and 2012, but the growth rate varied during that time span. Between 2003 and 2008, the percentage of hospital stays among adult patients with MCC increased by at least 2.0 percent per year, but beginning in 2009 the growth rate slowed to less than 2.0 percent per year. The percentage of stays among adults with MCC is projected to continue to increase from 2012 to 2014 at an average rate of 1.6 percent per year. This slowdown in growth of the projected percentage of stays for adults with MCC is expected for both sexes and all age groups.
  Overall, the percentage of nonmaternal hospital stays for adults with MCC grew fastest for younger adults. From 2003 to 2012, average annual growth in the percentage of hospital stays among adults with MCC was 1.8 times higher for patients aged 18–44 years than for patients aged 45–64 years and 3.4 times higher than for patients aged 65 years and older. Although projected growth between 2012 and 2014 in the percentage of stays for adults with MCC is lower than was actual growth between 2003 and 2012, it continues to reflect more rapid growth among the youngest age group (3.5 percent average annual increase among patients aged 18–44 years vs. 1.6 and 0.7 percent average annual increase among patients aged 45–64 years and 65 years and older, respectively).
  Although the overall percentage of hospital stays for adults with MCC was lowest for females aged 18–44 years, the average annual percentage increase was highest for this group compared with the other sex and age groups.
• Growth in average hospital costs has fluctuated over time but has generally increased in recent years, and this faster rate of growth is projected to continue through 2014.
  Mean hospital costs for nonmaternal stays among adults with MCC, adjusted for inflation, increased by an average of 1.5 percent per year between 2003 and 2012. Average hospital costs for this group grew relatively slowly (about 1.0 percent or less per year) from 2003 to 2005, moderately (around 2.0–4.0 percent per year, depending on the age/sex group) from 2006 to 2008 (with a slowdown in 2007), and slowly again in 2009 and 2010. Since 2011, the rate of growth in average hospital costs for adult patients with MCC has been moderate, and growth is projected to continue at a moderate pace from 2012 to 2014 (at an average annual rate of 2.9 percent). This moderate growth in projected costs is expected for all sex and age groups.

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 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 approximately 14,000 ICD-9-CM diagnosis codes.

CCS categorizes ICD-9-CM diagnoses into a manageable number of clinically meaningful categories.⁵ 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.

Case definition

For this report, hospital stays for patients with multiple chronic conditions (MCC) were defined as those with two or more chronic conditions. Chronic conditions were identified using the set of chronic conditions developed by the U.S. Department of Health and Human Services (HHS) Interagency Workgroup on MCC and the Office of the Assistant Secretary of Health.⁶ As reported by Goodman and colleagues (2013), 20 chronic conditions were identified with definitions for five selected HHS health data systems, including the HCUP Nationwide Inpatient Sample (NIS). For the HCUP inpatient databases, the 20 chronic conditions were defined using the Agency for Healthcare Research and Quality (AHRQ) Clinical Classifications Software (CCS), which groups together highly related diagnoses of the same condition. One condition, autism spectrum disorder, was defined for the NIS using ICD-9-CM diagnosis codes rather than CCS categories. Steiner and Friedman (2013) implemented these chronic condition definitions in a recent analysis of MCC using the 2009 NIS.⁷ The 20 chronic conditions and corresponding clinical coding criteria are provided in Table 2.

Table 2

Chronic conditions and clinical coding criteria.

Consistent with Steiner and Friedman (2013), we identified chronic conditions on the basis of the clinical coding criteria (listed in Table 2) indicated in either a principal or a secondary diagnosis code field on the discharge record. A chronic condition was counted only once per discharge regardless of the number of diagnosis codes (principal and secondary) that indicated the condition.

Maternal discharges were excluded from the analysis. Maternal discharges were identified as those with a major diagnostic category (MDC) code of 14, pregnancy, childbirth, and puerperium.

Average annual percentage change

Average annual percentage change was calculated using the following formula:

Types of hospitals included in the HCUP State Inpatient Databases

This analysis used State Inpatient Databases (SID) limited to 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). Community hospitals include obstetrics and gynecology, otolaryngology, orthopedic, cancer, pediatric, public, and academic medical hospitals. Excluded for this analysis are long-term care facilities such as 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 was included in the analysis.

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 1 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 based on hospital accounting reports from the Centers for Medicare & Medicaid Services (CMS).⁸ Costs 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-wide cost-to-charge ratio is used. 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 were weighted to produce annual costs. Quarterly and annual costs were adjusted for inflation using the Gross Domestic Product (GDP) from the U.S. Department of Commerce, Bureau of Economic Analysis (BEA), with 2014 as the index base.⁹ That is, all costs are expressed in 2014 dollars.