DHSC Statsheet Delaware Health Statistics Center Division of Public Health Department of Health and Social Services November 30, 2007 Methicillin-Resistant Staphylococcus Aureus (MRSA) Associated Hospitalizations in Delaware Hospitalizations of patients with an MRSA infection are associated with: 1) longer stays; 2) higher charges; and 3) greater risk of mortality. The number of hospital discharges with a secondary diagnosis of MRSA has risen from 20 in 1994 to 874 in 2005. MRSA infections have received increasing attention as the number of people diagnosed with both healthcare- and community-acquired infections has risen. An October JAMA report estimated that community-acquired MRSA accounted for 14 percent of all MRSA infections in 20054. Though distinguishing between healthcare- and community-acquired types of MRSA cannot be determined by hospital discharge data alone, the most serious cases of MRSA that require hospitalization are captured by the data, providing a valid insight to the trend in MRSA hospitalizations. Each hospital discharge record has one primary and up to eight secondary diagnoses. Because MRSA infections can only be listed as a secondary diagnosis, MRSA associated hospitalizations were identified by the presence of ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) discharge diagnosis code V09.0 in any one of the secondary diagnoses. As shown in Figure 1, the number of MRSA discharges in Delaware hospitals more than tripled from 2000 to 2005, with a 64 percent increase from 2004 to 2005. In 2005, the 874 hospitalizations associated with MRSA infections represented .8 percent of all hospital discharges, a proportion similar to national estimates3. Patient Characteristics Males accounted for 51 percent of MRSA associated discharges in 2005, though females comprised the majority of all non-MRSA discharges (see Table 1). The age distribution for MRSA discharges differed from non-MRSA discharges; proportionately there were fewer patients under 1, and more patients ages of 18-44 and 45-64. The majority (68.4 percent) of MRSA associated hospitalizations were admitted from the emergency department; admissions from physicians accounted for 26.8 percent of MRSA discharges. Similar to the results found in national studies1, MRSA associated hospitalizations in Delaware had longer average stays and higher total charges than non-MRSA hospitalizations. The average length of stay was almost 3 days longer for MRSA hospitalizations. The average charge for MRSA hospitalizations was $21,471 compared to an average of $16,531 for non-MRSA hospitalizations. The proportion of in-hospital deaths was not significantly higher for MRSA associated discharges, though differences existed in patients discharged to their home, other health care facilities, and home health care. Patients with an MRSA infection were less likely to be discharged home, and more likely to be discharged to either another health care facility or home health care, than patients without an MRSA infection. Diagnoses In 2005, the most common primary diagnosis associated with an MRSA infection was skin and subcutaneous tissue infections, which accounted for almost one third of all MRSA associated discharges (see Table 2). Complications of surgical procedures or medical care was the second most frequently occurring primary diagnosis, comprising 8 percent of all MRSA discharges, followed by pneumonia and complications of device, implant, or graft, both of which accounted for just over 6 percent of the total MRSA hospitalizations. In 1995, septicemia was the most common primary diagnosis and skin and subcutaneous tissue infections accounted for only 4.3 percent of all MRSA associated discharges. In 2000, that proportion was stable at 4.9; by 2005 it had increased to 32.8 percent and was the principal diagnosis most frequently associated with a secondary diagnosis of MRSA. Procedures Each hospital discharge record can have anywhere from zero to six listed procedures. In 2005, 31 percent of MRSA associated discharges had no procedures; out of the remaining 69 percent, there were 1330 total procedures performed. The most commonly performed procedures were incision and drainage of the skin and subcutaneous tissue, other vascular catheterization, and debridement of wound (see Table 3). Both incision and drainage and debridement of wound are related to the surgical treatment of skin infections and account for almost one-quarter of all procedures performed during an MRSA associated hospitalization. CCS Primary Diagnoses Frequency Percent 1 Skin and subcutaneous tissue infections 287 32.8 2 Complications of surgical procedures or medical care 70 8.0 3 Pneumonia (except that caused by tuberculosis or STD) 55 6.3 4 Complication of device; implant or graft 55 6.3 5 Septicemia (except in labor) 43 4.9 6 Infective arthritis and osteomyelitis (except that caused by tuberculosis or STD) 30 3.4 7 Chronic obstructive pulmonary disease and bronchiectasis 26 3.0 8 Other connective tissue disease 20 2.3 9 Respiratory failure; insufficiency; arrest (adult) 19 2.2 10 Urinary tract infections 19 2.2 Table 3. Most Common All-listed Procedures for Discharges with a Secondary Diagnosis of MRSA CCS All-listed Procedures Frequency Percent 1 Incision and drainage; skin and subcutaneous tissue 185 13.9 2 Other vascular catheterization; not heart 161 12.1 3 Debridement of wound; infection or burn 125 9.4 4 Other diagnostic procedures (interview ; evaluation; consultation) 98 7.4 5 Respiratory intubation and mechanical ventilation 68 5.1 6 Other non-OR therapeutic procedures on skin and breast 54 4.1 7 Other therapeutic procedures on muscles and tendons 47 3.5 8 Hemodialysis 38 2.9 9 Partial excision bone 30 2.3 10 Diagnostic ultrasound of heart (echocardiogram) 28 2.1 References: 1. Elixhauser A, Steiner C. Infections with Methicillin-Resistant Staphylococcus Aureus (MRSA) in U.S. Hospitals, 1993-2005. July 2007. U.S. Agency for Healthcare Research and Quality. 2. Kuehnert MJ, Hill HA, Kupronis BA, Tokars JI, Solomon SL, Jernigan DB. Methicillin-resistant– Staphylococcus aureus Hospitalizations, United States. Emerg Infect Dis. Vol. 11, No. 6, June 2005. [accessed 11.1.07]. Available from http://www.cdc.gov/ncidod/EID/vol11no06/04-0831.htm. 3. Noskin GA, Rubin RJ, Schentag J, Kluytmans J, Hedblom E, Smulders M, Lapetina E, Gemmen E. The Burden of Staphylococcus aureus Infections on Hospitals in the United States: An Analysis of the 2000 and 2001 Nationwide Inpatient Sample Database. Arch Intern Med, Aug 8/22, 2005; 165: 1756 - 1761. 4. Klevens RM, Morrison MA, Nadle J, Petit S, Gershman K, Ray S, Harrison LH, Lynfield R, Dumyati G, Townes JM, Craig AS, Zell ER, Fosheim GE, McDougal LK, Carey RB, Fridkin SK. Invasive Methicillin-Resistant Staphylococcus aureus Infections in the United States. JAMA 2007 298: 1763-1771. 5. Crowcroft NS, Catchpole M. Mortality from methicillin resistant Staphylococcus aureus in England and Wales: analysis of death certificates. BMJ, Dec 2002; 325: 1390 - 1391. Printed copies of tables, graphs, and charts can by obtained by contacting: Delaware Health Statistics Center Delaware Division of Public Health 417 Federal Street Dover, Delaware 19901 (302) 744-4541 Doc # 35-05-20/07/11/09