AHRQ Stats: MRSA in California

In 2013, 8 percent of patients in California with MRSA (methicillin-resistant Staphylococcus aureus) acquired the infection during a hospital stay. (Source: Agency for Healthcare Research and Quality, Healthcare Cost and Utilization Project Statistical Brief #212, Hospital-, Health Care-, and Community-Acquired MRSA: Estimates From California Hospitals, 2013.)

Hospital-, Health Care-, and Community-Acquired MRSA: Estimates From California Hospitals, 2013 #212

Hospital-, Health Care-, and Community-Acquired MRSA: Estimates From California Hospitals, 2013

Janet P. Sutton, Ph.D., and Claudia A. Steiner, M.D., M.P.H.

Introduction

Methicillin-resistant Staphylococcus aureas (MRSA) is a bacterium that is resistant to many of the most commonly prescribed beta-lactam antibiotics, including penicillin, amoxycillin, oxacillin, and methicillin. Severe cases of MRSA may result in endocarditis, osteomyelitis, septicemia, or even death. Each year MRSA accounts for approximately 11,000 deaths in the United States.¹ Costs associated with a MRSA infection are high, with an average hospital length of stay of 10 days and average hospital costs of $14,000. The average length of stay and hospital costs associated with MRSA are approximately 2 times higher than those of other hospital stays.²

MRSA typically is classified as hospital acquired; health care acquired, community onset; or community acquired, community onset. Hospital-acquired MRSA usually is the result of a nosocomial infection, often acquired following a surgical or invasive medical procedure during a hospital stay. Health care-acquired MRSA develops outside the hospital while the patient is in the community and has had recent contact or received treatment in a health care facility, such as an inpatient hospital, ambulatory surgical center, dialysis center, or nursing facility.³ Community-acquired MRSA occurs among community-dwelling individuals without recent hospitalization or encounters with the health care system.

Centers for Disease Control and Prevention data indicate that between 2005 and 2011 the incidence of hospital-acquired MRSA dropped by more than 50 percent. During this same period the incidence of community-acquired MRSA decreased by only 5 percent.⁴

This HCUP Statistical Brief examines inpatient hospital stays with MRSA in California in 2013. Inpatient stays are categorized by clinical condition associated with MRSA—pneumonia, septicemia, cellulitis or skin ulcers, complications following surgery or medical care, and other clinical conditions. Patients with a MRSA-associated hospital admission who acquired the infection during the course of the hospitalization are then compared with those who acquired the infection following receipt of treatment or care in a health care facility in the past 90 days or who acquired the infection in the community. Health care facilities include inpatient hospital settings, emergency departments, and ambulatory surgery facilities. Differences greater than 10 percent are noted in the text.

Findings

Hospital inpatient stays with MRSA, California, 2013
Figure 1 presents data on the percentage of MRSA-related inpatient stays in California hospitals by clinical condition. If a patient had more than one stay in the year, each inpatient stay is counted separately.

Highlights

In 2013, over 1 out of 100 inpatient stays at California hospitals—a total of 37,627 stays—had a principal or secondary MRSA diagnosis.

A total of 42 percent of MRSA-related hospitalizations included a cellulitis or skin ulcers diagnosis. About 17 percent of stays had MRSA pneumonia, and 16 percent had MRSA septicemia.

Over 17 percent of patients with a MRSA diagnosis were hospitalized with MRSA two or more times during the year.

Only 8 percent of patients developed MRSA during a hospital stay. About 42 percent of patients with a MRSA-related hospital stay had been hospitalized, were seen in the emergency department, or had undergone ambulatory surgery in the 90 days prior to the MRSA stay. About 50 percent of patients were hospitalized with community-acquired MRSA.

Half of patients with community-acquired MRSA had a diagnosis of cellulitis or skin ulcers. Among patients with hospital-acquired MRSA, the largest proportion (38 percent) were diagnosed with pneumonia.

Figure 1. MRSA-associated inpatient stays in California hospitals by clinical condition associated with MRSA, 2013

Abbreviation: MRSA, methicillin-resistant Staphylococcus aureas
Source: Agency for Healthcare Research and Quality (AHRQ), Center for Delivery, Organization, and Markets, Healthcare Cost and Utilization Project (HCUP), State Inpatient Database (SID), California, 2013

Figure 1 is a pie chart that shows the percentage of MRSA-associated hospital stays in California in 2013 by clinical condition associated with MRSA. Septicemia: 15.9; pneumonia: 17.0; cellulitis and skin ulcers: 41.9; complications of surgery or medical care: 7.4; other: 17.8.

In California in 2013, 1 out of every 100 inpatient stays involved MRSA.

Approximately 1.2 percent of the over 3.1 million hospital stays that occurred in California in 2013—a total of 37,627 stays—had either a principal or a secondary MRSA diagnosis. Thus, in California, just over 1 out of every 100 hospital stays in 2013 involved MRSA.

Over 40 percent of MRSA hospital stays were associated with a diagnosis of cellulitis or skin ulcers.

MRSA cellulitis and skin ulcers accounted for 41.9 percent of all MRSA inpatient stays. MRSA pneumonia and septicemia accounted for 17.0 percent and 15.9 percent of MRSA stays, respectively. Complications following surgery or medical care accounted for 7.4 percent of MRSA hospital stays.

Unspecified bacterial infection was the leading diagnosis among MRSA-associated hospital stays categorized as involving other clinical conditions.

Among MRSA stays with other clinical conditions (i.e., those without a diagnosis of septicemia, pneumonia, cellulitis or skin ulcers, or complications of surgery or medical care), approximately 10.2 percent had a diagnosis involving an unspecified bacterial infection. Nutritional, endocrine, and metabolic disorders accounted for 3.5 percent of other MRSA hospital stays, and fluid and electrolyte disorders, anemia, and diabetes mellitus with complications each accounted for about 3 percent of other MRSA hospital. Data are not shown.

Figure 2 displays the number of single and multiple hospitalizations among patients with a MRSA-associated admission that occurred during 2013. The subsequent analyses track patients across multiple MRSA hospitalizations. Patients are counted once rather than counting each hospital stay.

Figure 2. Percentage distribution of the number of MRSA-associated hospital stays among patients with at least one MRSA admission in California, 2013

Abbreviation: MRSA, methicillin-resistant Staphylococcus aureas
Note: Patients were categorized according to their total number of inpatient stays with a MRSA diagnosis with no restriction on the number of days between MRSA admissions. Source: Agency for Healthcare Research and Quality (AHRQ), Center for Delivery,
Organization, and Markets, Healthcare Cost and Utilization Project (HCUP), State Inpatient Database (SID), California, 2013

Figure 2 is a pie chart that shows the percentage distribution of MRSA-associated hospital stays among patients with at least one MRSA admission in California in 2013. Patients with 1 MRSA hospitalization: 82.8; 2 MRSA hospitalizations: 12.4; 3+ MRSA hospitalizations: 4.8.

More than 1 out of 6 patients with a MRSA-associated admission were hospitalized on two or more occasions.

During 2013, 12.4 percent of patients with MRSA experienced two hospitalizations and 4.8 percent of patients had three or more MRSA-associated admissions. Accounting for multiple hospitalizations, a total of 31,448 patients were admitted to a California hospital with a MRSA-associated diagnosis in 2013.

Table 1 presents data on the demographic characteristics of the 31,448 patients who were hospitalized with a MRSA diagnosis in 2013.