Inpatient Operating Room Procedures in Hospitals in the United States in 2007

Hospital care is a major portion of healthcare expenditures, representing 30.7% of all healthcare expenditures in the United States. Because operating room (OR) procedures, a major reason for hospital use, are highly invasive and expensive, understanding OR procedures provides information about how healthcare resources are used, according to researchers. The researchers continued by noting that, to date, there have been relatively few studies on the epidemiology and resource use of OR procedures in general. They recently conducted a study designed to provide an overview of inpatient OR procedures in the United States, describing the volume of inpatient OR procedures, associated resource use, the most frequent and expensive OR procedures, and trends in inpatient OR procedure use from 1997 to 2007.

tudy results were reported in Archives of Surgery [2010;145(12):1201-1208]. The study utilized data from the Nationwide Inpatient Sample (NIS) for the Agency for Healthcare Research and Quality’s Healthcare Cost and Utilization Project. The 2007 NIS included data from 1044 hospitals drawn from a sampling frame of a census of hospitals from 40 states that composed 90% of all discharges in the United States. The discharges were from short-term, acute care, and nonfederal hospitals. The NIS included up to 15 procedure codes from the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). The OR procedures included in the analysis were defined using procedure classes, which categorize each ICD-9-CM procedure code as major therapeutic, major diagnostic, minor therapeutic, or minor diagnostic. Major procedures are valid OR procedures according to diagnosis-related groups as determined by physician panels that classified procedure codes based on whether the procedure would be performed in an OR in most hospitals.

There were approximately 15 million OR procedures performed in hospitals in the United States in 2007 (a rate of 495 OR procedures per 10,000 population); the OR procedures were performed as part of 10.4 million hospitalizations. Although 26.4% of all hospitalizations involved an OR procedure, the stays related to OR procedures accounted for 46.8% of hospital costs ($161 billion). Individuals 45 to 64 years of age received the most procedures (32.1% of all procedures). Of the total OR procedures, 61.7% were performed on females for a rate of 603 procedures/10,000 females compared with 381 procedures per 10,000 males (P<.001). There were no differences in procedure rates based on community median household income or by rural or urban residence of the patients, but procedure rates in the West were lower than those in other regions (P=.02). Compared with non-OR patients, patients who underwent OR procedures were less severely ill; 20.5% of OR patients fell into the group with the highest severity of illness compared with 24.6% of non-OR patients (P<.001).

More than half of OR patients (53.8%) were admitted electively to the hospital compared with 14.2% for non-OR patients. The mean length of stay was longer for OR-related stays compared with non-OR stays (5.3 days vs 4.3 days; P<.001). Mean cost per stay was nearly 2.5 times higher for stays related to OR procedures compared with non-OR stays ($15,400 vs $6300, respectively; P<.001). The 15 most expensive procedures accounted for 51.2% of all hospital costs related to OR procedures and 24.0% of all hospital costs. Between 1997 and 2007, volumes for 4 of those 15 most costly procedures increased: 20% for percutaneous transluminal coronary angioplasty (PTCA), 46% for cesarean delivery, 46% for knee replacement, and 45% for spinal fusion. The researchers noted, however, that “PTCA experienced a significant reversal in its steady climb, decreasing 20% in 1 year after a 56% increase in the prior decade.” In summary, the researchers said that “procedures in the OR represent a large portion of hospital costs, and these costs are concentrated in few procedure types.”