Ambulatory surgery, or outpatient surgery, is a planned surgical episode where the patient requires less than a 24-hour hospital stay. The use of ambulatory surgery as an alternative to inpatient surgery has become more common, and outpatient surgeries account for a growing proportion of surgeries performed in hospitals. In 2002, outpatient surgeries accounted for 63 percent of all surgeries performed in community hospitals nationally, compared with only 16 percent in 1980.1 The overall increase in ambulatory surgeries can be explained primarily by two major factors. First, advances in surgical technology and anesthesia have made surgery easier on patients and increased the demand for outpatient care. Second, health care policies have created economic incentives that encourage ambulatory surgery.2
Ambulatory Surgery in U.S. Hospitals, 2003 summarizes information about hospital-based ambulatory surgeries for 17 States based on data from two databases maintained by the Agency for Healthcare Research and Quality (AHRQ): the State Ambulatory Surgery Databases (SASD) and the State Inpatient Databases (SID). These data sources are used to examine a cross section of surgeries performed in inpatient and outpatient settings in order to assess differences in the utilization and cost of various surgical procedures across these settings. This report provides insight for individuals interested in gaining a better understanding of characteristics of ambulatory surgeries. Additionally, comparisons between surgeries performed in the outpatient and inpatient settings are noted. This Fact Book addresses the following:
In addition, this Fact Book provides detailed statistics on:
| In the 17 States covered in this report, nearly 52 percent of surgical encounters occurred in the outpatient hospital setting, ranging from 42 percent to 66 percent. |
Based on data from the 17 States examined for this report, more than 3.9 million ambulatory surgical visits took place in 2003, totaling $18.3 billion in aggregate charges. These visits resulted in over 4.9 million surgeries. Overall, 52 percent of surgical visits and stays were ambulatory in nature, but this percentage varied by State—from 42 percent to 66 percent in the 17 States covered in this report. In 2003, this translated to approximately 4,100 ambulatory surgical visits per 100,000 individuals, compared with 3,800 inpatient surgical stays per 100,000 individuals.3 The majority of ambulatory surgical visits occurred in large, metropolitan, private not-for-profit, non-teaching hospitals. Almost 13 percent took place in non-Federal government hospitals and 9 percent in for-profit hospitals.
| Almost 4,100 ambulatory surgical visits per 100,000 individuals took place in acute care hospitals compared with 3,800 inpatient surgical visits per 100,000 individuals. |
Females had more ambulatory surgeries than males in 2003. Of the 3.9 million ambulatory surgical visits studied in this report, 59 percent were performed on females. The gender distribution of ambulatory and inpatient surgical encounters was very similar, with more females than males obtaining surgeries in both settings.
The distribution of ambulatory surgical visits varied by age group. Patients ages 18 to 44 accounted for nearly 33 percent of these visits—more than any other age group. Most inpatient surgical stays occurred among patients 65 and older.
In 2003, about 90 percent of ambulatory surgeries were for therapeutic reasons, while the remaining surgeries were for diagnostic reasons. Lens and cataract surgery was the most common ambulatory surgery and resulted in nearly 9 percent of all outpatient surgeries. Removal of the tonsils and/or adenoids and myringotomy (ear tube surgery), procedures generally performed on children and adolescents, accounted for 4 and 3 percent, respectively, of all ambulatory surgeries. Lumpectomy and diagnostic dilatation and curettage (D&C)—two surgeries primarily or exclusively performed on women—each resulted in approximately 3 percent of all ambulatory surgeries.
Three of the 10 most common ambulatory surgery procedures were related to treating or diagnosing musculoskeletal system disorders: other therapeutic procedures on the muscles and tendons, other operating room (O.R.) therapeutic procedures on the joints, and excision of the semilunar cartilage of the knee. Other common ambulatory surgeries included hernia repair and cholecystectomy (surgical removal of the gallbladder).
| Lens and cataract surgery was the most commonly performed ambulatory surgery in 2003. |
| About 9 in 10 ambulatory surgeries were performed for therapeutic purposes while only 1 in 10 was used to diagnose disorders. |
In 2003, procedures related to the musculoskeletal system were performed in nearly 26 percent of all ambulatory surgeries. Ambulatory surgeries accounted for the majority of surgeries performed on the musculoskeletal system, eye, integumentary system, ear, and nose, mouth, and pharynx. In fact, surgeries related to the eye, ear, and nose, mouth, and pharynx were 90 to 98 percent outpatient. Conversely, surgeries performed to treat and/or diagnose disorders of the digestive, nervous, cardiovascular, male genital, heme and lymphatic, respiratory, and endocrine systems, as well as obstetrical surgeries, were primarily inpatient.
In 2003, lens and cataract surgery was the most common ambulatory surgery performed for males and females. In total, 4 of the 10 most common ambulatory surgeries were performed on both males and females, with lens and cataract surgery being the most common. The next three included other therapeutic procedures on muscles tendons, other O.R. procedures on the joints, and tonsillectomy and/or adenoidectomy. However, there was some variation in which outpatient surgical procedures were utilized most frequently by gender. For example, hernia repair, excision of the semilunar cartilage of the knee, myringotomy, other O.R. therapeutic procedures on the nose, mouth, and pharynx, and arthroscopy were among the top 10 procedures for males but not for females. Cholecystectomy, decompression of the peripheral nerve, and other O.R. therapeutic procedures on the skin and breast were top 10 surgeries performed on females but not performed as often on males. Three of the top 10 surgeries for females related to female-specific procedures—lumpectomy, diagnostic D&C, and other excision of the cervix and uterus. Transurethral excision, drainage, or removal of a urinary obstruction—a male-specific procedure—was among the top 10 ambulatory surgeries performed on males.
The most common surgeries performed in ambulatory settings varied considerably by age. Only 3 ambulatory surgeries were commonly performed across each age group: hernia repair, other therapeutic procedures on muscles and tendons, and other O.R. therapeutic procedures on joints. Other excision of the cervix and uterus, diagnostic D&C, and lumpectomy accounted for 3 of the most common ambulatory surgeries performed on patients ages 18 to 44. Approximately 1 in 5 surgeries performed on patients ages 45 to 64 were used to treat or diagnose musculoskeletal system disorders. Nearly 32 percent of ambulatory surgeries for patients ages 65 and older involved cataract and lens procedures—the most common surgery performed in an outpatient setting for this age group.
| The most common ambulatory surgery performed for both genders was lens and cataract surgery. This procedure was also common among patients 65 and older, accounting for nearly 32 percent of all ambulatory surgery procedures in this population. |
In 2003, the average charge for an ambulatory surgical visit was $5,600, compared with $28,300 for an inpatient surgical stay. Five of the 10 surgeries associated with the most expensive ambulatory surgical visits involved the treatment and diagnosis of cardiovascular disorders: percutaneous coronary angioplasty (PTCA), insertion of a cardiac pacemaker or defibrillator, other O.R. heart procedures, endovascular repair of an aneurysm, and other O.R. procedures on vessels other than the head and neck. Two of the 10 most expensive ambulatory surgeries were related to musculoskeletal system disorders: spinal fusion and laminectomy. Open prostatectomy—a procedure performed only on men—was the fifth most expensive ambulatory surgery. Collectively, the most expensive ambulatory surgeries were not very common, and represented less than 4 percent of all outpatient surgical visits.
| The average charge for an ambulatory surgical visit was $5,600, compared with $28,300 for an inpatient surgical stay. |
| Collectively, the 10 costliest ambulatory surgeries were performed in less than 4 percent of all ambulatory surgical visits. |
In 2003, private insurance was billed for approximately 55 percent of ambulatory surgical visits compared with 46 percent of inpatient surgical stays. Government insurance programs (Medicare and Medicaid) were billed for about one-third of ambulatory surgical visits. In contrast, nearly half of all inpatient surgical stays were billed to the government. Less than 4 percent of ambulatory surgical visits were uninsured.
In 2003, Medicare, the federally sponsored health care program for the elderly and disabled, served approximately 14.6 million individuals in the 17 States examined, most of whom were 65 years and older.4 Medicare was billed for approximately 24 percent of ambulatory surgeries, while only 13 percent of the population in these states was covered by Medicare. The most common ambulatory surgery billed to Medicare was lens and cataract surgery. Approximately 75 percent of outpatient surgeries related to lens and cataract procedures were billed to Medicare. Transurethral excision, drainage, or removal of a urinary obstruction, and decompression of the peripheral nerve were among the top 10 ambulatory surgeries billed to Medicare, but were not top 10 outpatient surgeries billed to other payer groups.Medicare was billed for 40 percent and 24 percent, respectively, of all ambulatory surgeries related to these procedures.
| Lens and cataract surgery was the most common ambulatory surgery billed to Medicare. |
Medicaid, the federally and State-sponsored health care program for low-income people, served about 12.7 million individuals in the 17 States examined.4 In 2003, approximately 12 percent of the population in these states was covered by Medicaid, and this program was billed for 12 percent of all ambulatory surgical visits.Women and children continue to comprise a large portion of Medicaid's enrollment, which resulted in Medicaid being billed for a large share of certain surgeries.
Two of the top 10 ambulatory surgeries billed to Medicaid are primarily performed in children: myringotomy (ear tube surgery) and removal of the tonsils and adenoids. Medicaid was billed for 27 percent of outpatient myringotomies and for 23 percent of outpatient surgeries involving the removal of the tonsils and adenoids. Other excision of the cervix and uterus, diagnostic D&C, and lumpectomy were 3 of the most common ambulatory surgeries billed to Medicaid in 2003.
In 2003, more than 78.3 million individuals in the 17 States examined had private health insurance through commercial insurance plans.4 These plans included employer-sponsored health plans and selfpurchased plans. Commercial health plans were billed for approximately 55 percent of all ambulatory surgical visits. Almost 13 percent of all ambulatory surgeries billed to private insurers were for the treatment and diagnosis of musculoskeletal system disorders. An even larger proportion of charges associated with these surgeries, more than 50 percent, were billed to private insurers. Approximately 3 out of 4 ambulatory surgeries involving diagnostic D&C and other excision of the cervix and uterus were billed to private insurers. Private insurers were billed for 71 percent of ambulatory surgeries involving the removal of the tonsils and adenoids.
| Private insurers were billed for approximately 3 out of 4 ambulatory surgeries involving dilation and curettage (D&C) and other excision of the cervix and uterus. |
In 2003, about 14.9 million individuals, about 14 percent of the population in the 17 states evaluated, had no health insurance.4 However, only 3 percent of ambulatory surgical visits were performed on uninsured patients. Approximately 1 in 6 ambulatory surgeries performed on uninsured people were related to other O.R. therapeutic procedures on the skin and breast. Nine of the 10 most common ambulatory surgeries performed on the uninsured were the same surgical procedures commonly performed on patients ages 18 to 44.
Improvements in technologies have influenced a transition from inpatient to outpatient surgical settings. Examples of surgical procedures that reflect evolving patterns of care because of advances in technology include:
Approximately 16 percent of appendectomies were performed in an ambulatory setting. Over 98 percent of all appendectomies were performed on patients younger than 65, with more than 6 in 10 outpatient appendectomies performed on patients ages 18 to 44. Unlike in younger age groups, the proportion of inpatient appendectomies was significantly higher than the proportion of outpatient appendectomies performed on patients 65 and older. There were also gender differences in the use of inpatient or ambulatory settings for appendectomies. Although the number of inpatient appendectomies performed on males and females was virtually equal, the proportion of females receiving these procedures in an outpatient setting was somewhat higher than in the inpatient setting—53 percent versus 47 percent.
Approximately two-thirds of all appendectomies were billed to private insurers. However, this rate also varied by setting, with a greater proportion of outpatient appendectomies billed to private insurers, as compared with inpatient appendectomies.
Half of all surgeries involving a cholecystectomy were performed on an outpatient basis. On average, patients receiving a cholecystectomy in an ambulatory setting were about 8 years younger than those receiving an inpatient cholecystectomy. Outpatient cholecystectomies were most often performed on patients ages 18 to 44, followed closely by patients ages 45 to 64. Although the percentage of outpatient cholecystecomies was higher or equal to the percentage of inpatient cholecystecomies performed on patients younger than 65, this was not the case for the elderly. The proportion of inpatient cholecystectomies performed on patients 65 and older (34 percent) was over twice that of outpatient cholecystectomies (14 percent).
More than 3 out of 4 outpatient cholecystectomies were performed on females, while this group accounted for 2 out of 3 cholecystectomies performed on an inpatient basis. Compared with inpatient cholecystectomy procedures, the proportion of outpatient cholecystectomies billed to private insurers was considerably higher—66 percent versus 43 percent. Consequently, the proportion of outpatient procedures billed to Medicare was lower than the proportion of inpatient procedures billed to Medicare—15 percent versus 34 percent, respectively.
Nearly 89 percent of hernia repairs were performed on an outpatient basis. On average, patients who received a hernia repair in an ambulatory setting were 12 years younger than those patients receiving an inpatient hernia repair. In fact, more than 3 out of 4 outpatient hernia repairs were performed on patients younger than 65, while over half of all inpatient hernia repairs were performed on patients 65 and older. Consequently, the proportion of inpatient hernia repairs performed on patients 65 and older (54 percent) was more than twice the proportion performed in the outpatient setting for this age group (25 percent). Similarly, the occurrence of these surgeries among females was more than twice as high in the inpatient setting compared with the outpatient setting—24 percent versus 11 percent. Private insurers were billed for the highest proportion of outpatient hernia repairs (58 percent), which likely reflects the age differences among outpatient and inpatient hernia repairs. Medicare was billed for the highest proportion of inpatient hernia repairs (51 percent).
| Females accounted for about 1 in 10 outpatient hernia repairs; but in the inpatient setting, nearly 1 in 4 of these surgeries was performed on females. |
Only 3 percent of bariatric surgeries were performed on an outpatient basis. The mean age for bariatric surgery was approximately 42 years, regardless of inpatient or outpatient status, and almost all bariatric surgeries performed in an ambulatory setting occurred in patients ages 18 to 64.Moreover, nearly 83 percent of outpatient bariatric surgeries were performed on females, which is similar to the proportion of inpatient bariatric surgeries performed on females. Not surprisingly, private insurers were billed for 8 out of 10 outpatient bariatric surgeries, while only 5 percent of these surgeries were billed to government payers (Medicare and Medicaid). The rate of outpatient bariatric surgeries billed to uninsured patients was almost 5 times the rate of inpatient bariatric surgeries billed to this group.
| Uninsured patients represented almost 12 percent of outpatient bariatric surgeries, while only 2 percent of inpatient bariatric surgeries were uninsured. |
Certain surgical procedures are performed primarily or exclusively in children, women, or men. These include:
Nearly all (96 percent) of tonsillectomy and/or adenoidectomy procedures performed in children occurred in an ambulatory setting. The mean age for a tonsillectomy and/or adenoidectomy was approximately 7 years, regardless of whether the procedure took place in an inpatient or outpatient setting. Although the percentage of outpatient tonsillectomies and/or adenoidectomies performed in boys and girls was virtually equal, these procedures were performed more often as inpatient surgeries in boys (57 percent versus 43 percent). Outpatient tonsillectomies and/or adenoidectomies were most often billed to private insurance, but the proportion of outpatient surgeries billed to private insurers was considerably higher compared with the proportion of inpatient surgeries billed to this payer—67 percent versus 54 percent. Consequently, the proportion of outpatient procedures billed to Medicaid was lower than the proportion of inpatient procedures billed to Medicaid—28 percent versus 41 percent, respectively.
Nearly 22 percent of mastectomies in women were performed in an ambulatory setting. Over half of all outpatient mastectomies occurred in women ages 45 to 64, but the percentage of mastectomies performed in an ambulatory setting decreased significantly as women aged. The percentage of inpatient mastectomies performed on women ages 45 to 64 and women 65 and older was nearly equal. More than half of outpatient mastectomies were billed to private insurers, and Medicare was billed for almost one-third of these surgeries.
| About 22 percent of mastectomies were performed in an ambulatory setting. |
Less than 9 percent of hysterectomies were performed in an ambulatory setting. Over half of all hysterectomies were performed on women ages 18 to 44, followed by nearly 40 percent for women ages 45 to 64. However, this distribution differed significantly for women receiving this surgery in an outpatient venue. In fact, women ages 18 to 44 accounted for 67 percent of outpatient hysterectomies, while less than one-third of these outpatient surgeries were performed on women ages 45 to 64. Private insurers were billed for approximately 81 percent of outpatient hysterectomies. While 11 percent of outpatient hysterectomies were billed to government insurance programs (i.e., Medicare and Medicaid), nearly 22 percent of inpatient hysterectomies were billed to government payers.
About 20 percent of transurethral prostatectomies were performed in an ambulatory setting. Men receiving TURPs on an outpatient basis were slightly younger than men receiving inpatient TURPs (69 years versus 73 years, respectively). The percentage of outpatient TURPs performed on men ages 45 to 64 (31 percent) was considerably higher than the percentage of inpatient TURPs performed on this age group (19 percent). In contrast, the reverse was true for patients 65 and older, where the percentage of inpatient TURPs performed in this age group was 81 percent compared with 68 percent for outpatient TURPs. Because this procedure was performed most often on men 65 and older, Medicare was billed for the majority of both outpatient and inpatient TURP procedures. However, private insurers were billed for about 32 percent of hospital charges when this procedure was performed on an outpatient basis compared with only 18 percent of charges when performed in an inpatient setting.
The mission of the Agency for Healthcare Research and Quality (AHRQ) is to improve the quality, safety, efficiency, and effectiveness of health care for all Americans. To help fulfill this mission, AHRQ develops a number of powerful databases, including those created by the Healthcare Cost and Utilization Project (HCUP). HCUP is a Federal-State-Industry partnership designed to build a standardized, multi-State health data system. HCUP features databases, software tools, and statistical reports to inform policymakers, health system leaders, and researchers.
For data to be useful, they must be disseminated in a timely, accessible way. To meet this objective, AHRQ launched HCUPnet, an interactive, Internet-based tool for identifying, tracking, analyzing, and comparing statistics on hospital utilization, outcomes, and charges (http://hcupnet.ahrq.gov/). The online, menu-driven HCUPnet guides users in tailoring specific queries about hospital care online; with a click of a button, users receive answers within seconds.
To make HCUP data even more accessible, AHRQ disseminates HCUP Statistical Briefs, an online publication series that presents simple, descriptive statistics on a variety of specific, focused topics (http://www.hcup-us.ahrq.gov/reports/statbriefs.jsp). Statistical Briefs are made available regularly throughout the year and have covered topics such as hospitalizations among the uninsured, the national bill for hospital care by payer, and hospitalizations related to childbirth.
In addition, AHRQ produces the HCUP Fact Books to highlight statistics about hospital care in an easy-to-use, readily accessible format. Each Fact Book provides information about specific aspects of hospital care—the single largest component of the U.S. health care dollar. These national estimates are benchmarks against which States and others can compare their own data.
This Fact Book presents characteristics of hospital-based ambulatory surgeries in 2003. The State Ambulatory Surgery Databases (SASD) and the State Inpatient Databases (SID) are used to evaluate a cross-section of surgeries performed in inpatient and outpatient settings in order to examine differences in the utilization and cost of various surgical procedures in these settings. This report provides insight for individuals interested in gaining a better understanding of ambulatory surgery data and how these data compare with inpatient surgery data.
AHRQ welcomes questions and comments from readers of this report who are interested in obtaining more information about ambulatory surgeries in the United States.We also invite you to tell us how you are using this Fact Book and other HCUP data and tools and to share suggestions on how HCUP products might be enhanced to further meet your needs. Please E-mail us at hcup@ahrq.gov or send a letter to the address below.
Irene Fraser, Ph.D.
Director
Center for Delivery, Organization, and Markets
Agency for Healthcare Research and Quality
540 Gaither Road
Rockville, MD 20850
The State Ambulatory Surgery Databases (SASD) and the State Inpatient Databases (SID) are two in a family of databases and software tools developed as part of the Healthcare Cost and Utilization Project (HCUP). The SASD capture surgeries performed on the same day in which patients are admitted and released and contain clinical and resource use information included in a typical discharge abstract from hospital-based ambulatory surgery sites.i The SID contain clinical and resource use information from the universe of the inpatient discharge abstracts in participating States. This report includes data from 17 selected States who contributed to both the SASD and SID in 2003:
iData from freestanding ambulatory surgery sites have been excluded from this report.
Ambulatory surgery, or outpatient surgery, is a planned surgical episode where the patient requires less than a 24-hour stay. Outpatient procedures account for a growing proportion of surgeries performed in hospitals as the use of ambulatory surgeries as an alternative to inpatient surgery has become more common. Nationally, ambulatory surgeries accounted for 63 percent of all surgeries performed in community hospitals in 2002, compared with only 16 percent in 1980.1
Two major factors explain this overall growth in ambulatory surgeries (1) advances in surgical technology and anesthesia have made surgery easier on patients and increased the demand for outpatient care, and (2) health care policies have created economic incentives that encourage ambulatory surgery.2 For example, the Medicare program expanded coverage to ambulatory surgery centers and adopted a prospective payment system that created financial incentives for hospitals to shift patients to outpatient facilities.
As the number and type of surgeries performed in the outpatient setting have increased, so have concerns about cost, safety, and efficacy. There is particular concern about the safety of outpatient procedures for specific subgroups of patients, such as the elderly and children. A comparison of ambulatory surgery data to inpatient surgery data is essential for understanding the differences in utilization and costs for specific subpopulations and procedures.
This Fact Book summarizes hospital-based inpatient and outpatient surgery information from the State Inpatient Databases (SID) and the State Ambulatory Surgery Databases (SASD) maintained by the Agency for Healthcare Research and Quality (AHRQ). The SID contain the universe of the inpatient discharge abstracts in 38 Partner States. The SASD include surgeries performed on the same day in which patients are admitted and released and capture the vast majority of hospital-based ambulatory surgeries in 20 Partner States. This report examines 2003 inpatient and ambulatory surgery data from 17 selected States.
Because of their large size—13 million records in the 17 selected SID and 11 million records in the 17 selected SASD—these databases can provide information on relatively uncommon surgical procedures, as well as on subpopulations, such as specific or smaller age groups. The SID and SASD capture all types of patients discharged from hospitals, including the uninsured, those covered by public payers (Medicare and Medicaid), and those with private insurance. They also provide information on total hospital charges for all patients, unlike any other data source in the United States. This Fact Book addresses these central questions:
In addition, this Fact Book provides detailed statistics on:
A complete medical dictionary containing terms used in this Fact Book is available at http://www.nlm.nih.gov/medlineplus/mplusdictionary.html.