NOTE Antimicrobial stewardship program
NOTE
ar Layar
Impact of an antimicrobial stewardship program on patients with acute bacterial skin and skin structure infections Timothy R. Pasquale, Tamara L. Trienski, Deana E. Olexia, Joseph P. Myers, Michael J. Tan, Anthony K. Leung, Jose E. Poblete, and Thomas M. File Jr.
A
cute bacterial skin and skin structure infections (ABSSSIs) are an increasingly common reason for hospital admissions. 1,2 Such patients are commonly cared for by primary care clinicians and hospitalists. In recent years, hospitals have seen a 71% increase in the rate of hospitalizations due to ABSSSIs.2 Skin and soft-tissue infections are associated with substantial health care costs.1,3,4 In a matched cohort study, Hatoum et al.3 reported that patients with ABSSSIs spent a mean of 3.81 additional days in the hospital and incurred $14,794 in excess hospitalization charges compared with patients admitted without ABSSSIs. In a prospective, multicenter, observational study, Lipsky et al.5 found that patients with ABSSSIs had a mean length of stay (LOS) of 6.0 days. Jenkins and col-
Purpose. The impact of an antimicrobial stewardship program (ASP) on the management of therapy and hospital resources for patients with acute bacterial skin and skin structure infections (ABSSSIs) at a community teaching hospital was evaluated. Methods. A retrospective, observational chart review was performed to evaluate the impact of the ASP on patients admitted to Akron City Hospital with a diagnosis of ABSSSI between February 1 and August 20, 2012. Information on patient demographic characteristics, comorbidities, ABSSSI subtype, antibiotic therapy, microbiology, surgical interventions, and ASP recommendations was collected from medical records and the ASP intervention log. ASP recommendations were organized into five categories: dosage changes, de-escalation, antibiotic regimen change (i.e., change antibiotic regimen to a broad-spectrum antimicrobial or target a pathogen not being covered), infectious diseases (ID) formal consultation, and other.
Timothy R. Pasquale, Pharm.D., M.B.A., is Infectious Disease Clinical Specialist, Carolinas Healthcare System, Carolinas Medical Center, Charlotte, NC. Tamara L. Trienski, Pharm.D., is Clinical Lead Pharmacist, Antimicrobial Stewardship; and Deana E. Olexia, Pharm.D., is Clinical Staff Pharmacist, Summa Health System, Akron City Hospital, Akron, OH. Joseph P. Myers, M.D., is Vice President of Medical Affairs, Southwest Region, Summa Health System, Summa Barberton Hospital, Barberton, OH. Michael J. Tan, M.D., is Infectious Disease Physician; Anthony K. Leung, D.O., is Infectious Disease Physician; Jose E. Poblete, M.D., is Infectious Disease Physician; and Thomas M. File Jr., M.D., is Infectious Disease Physician, Summa Health System, Akron. Address correspondence to Dr. Pasquale (timothy.pasquale@ carolinashealthcare.org). Presented in part at the 50th Annual Meeting of the Infectious Diseases Society of America, San Diego, CA, October 2012.
1136
Am J Health-Syst Pharm—Vol 71 Jul 1, 2014
Results. A total of 62 patients were included in the study. A total of 85 recommendations were made to attending physicians for these 62 patients, with an acceptance rate of 95%. The most common interventions included dosage changes, deescalation, antibiotic regimen change, and ID consultation. When compared with historical data for 1149 patients, the intervention group had a significantly lower mean length of stay (LOS). The 30-day all-cause readmission rate was also significantly lower in the intervention group; however, the 30-day ABSSSI readmission rate did not differ significantly between groups. Conclusion. Interventions made by an ASP including a clinical pharmacist were associated with significant reductions in the mean LOS and 30-day all-cause readmission rate for patients with an ABSSSI compared with historical data. Am J Health-Syst Pharm. 2014; 71:1136-9
Dr. Pasquale has received funding from Forest Pharmaceuticals; has received speaker honorariums from Optimer Pharmaceuticals, Merck, and Cubist Pharmaceuticals; and has served on the pharmacy advisory board for Optimer Pharmaceuticals. Dr. Tan has received speaker honorariums from Cubist, Forest, Optimer, and Pfizer. Dr. Leung has served as a consultant for Merck and Vertex. Dr. File has served on the scientific advisory boards and as a consultant for Astellas, Bayer, Cubist, DaiichiSankyo, Durata, Forest, GlaxoSmithKline, Merck, Pfizer, and Tetraphase. The other authors have declared no potential conflicts of interest. Copyright © 2014, American Society of Health-System Pharmacists, Inc. All rights reserved, 1079-2082/14/0701-1136$06.00. DOI 10.2146/ajhp130677
NOTE Antimicrobial stewardship program
leagues6 concluded that frequent use of potentially unnecessary diagnostic studies, broad-spectrum antibiotic therapy, and prolonged treatment courses was common among adult patients hospitalized with ABSSSIs. Although ABSSSIs are among the most common infections requiring hospitalization, data regarding the use of ABSSSI-related resources and outcomes are lacking. An antimicrobial stewardship program (ASP) has the potential to improve the use of resources and outcomes for patients with ABSSSIs. In order to assess the impact of an ASP on the management of ABSSSIs, we evaluated the LOS and 30-day readmission rate for patients evaluated by the ASP at our community teaching hospital. Background Akron City Hospital (ACH) is a 577-bed, community teaching hospital within Summa Health System, which is a large integrated health care delivery system located in Akron, Ohio. In 2010, ACH initiated a comprehensive ASP. The ASP is led by a clinical pharmacist and an infectious diseases (ID) physician. The pharmacy department pays for 0.5 ID physician full-time equivalent for his or her participation in the ASP. The core antimicrobial stewardship strategy used is prospective audit with feedback. The clinical pharmacist and ID physician round daily, Monday through Friday, to review the identified patients and provide recommendations directly to physicians. Traditional targets of the ASP include patients receiving broad-spectrum antimicrobial therapy and high-cost antimicrobials. On February 1, 2012, an ABSSSItargeted approach to antimicrobial stewardship was incorporated as an additional method for the ASP to reduce costs. In 2011, the mean LOS for patients at ACH with ABSSSIs with an International Classification of Diseases, 9th Revision (ICD-9) codes
of 681–682.9 (cellulitis and abscess of finger and toe or other cellulitis and abscesses) was 6.2 days, and the 30-day ABSSSI readmission rate was 6.2%. The ASP clinical pharmacist identified patients via an emergency department admission list whose chief complaints were consistent with an ABSSSI. Patients without a formal ID consultation on admission were further evaluated by the ASP’s ID physician. The ID physician then reviewed patients’ clinical status and antimicrobial therapy regimen to provide feedback and recommendations to the attending physicians, most frequently a physician from the internal medicine service or a hospitalist. Methods A retrospective, observational chart review was performed to evaluate the impact of the ASP on patients admitted to ACH with a diagnosis of ABSSSI between February 1 and August 20, 2012. Patients were included in the analysis if the ASP intervened and the patient had a discharge ICD-9 code of 681–682.9. Information on patient demographic characteristics, comorbidities, ABSSSI subtype, antibiotic therapy, microbiology, surgical interventions, and ASP recommendations was collected from medical records and the ASP intervention log. ASP recommendations were organized into five categories: dosage changes, de-escalation (i.e., change antibiotic therapy to target a narrow spectrum of antimicrobial activity or decrease the number of antibiotics the patient was prescribed), antibiotic regimen change (i.e., change antibiotic regimen to a broad-spectrum antimicrobial or target a pathogen not being covered), ID formal consultation, and other. Chi-square analysis was performed on the frequency data to compare the intervention group with historical data, which included patients admitted to ACH in 2011 with ICD-9 codes of 681–682.9. The
Summa Health System institutional review board approved this study. Results During the study period, the ASP intervened on the care of 82 patients hospitalized with an ABSSSI. Of these, 62 had a discharge diagnosis consistent with ICD-9 codes 681–682.9 and were included in the analysis. The mean age of patients enrolled in the study was 55.8 years, 33 (53%) were men, 58 (94%) were Caucasian, and their mean Charlson comorbidity index7 score was 3. Other patient characteristics are listed in Table 1. The most common ABSSSI subtypes were cellulitis (76%, n = 47), major or deep abscess (26%, n = 16), and surgical-site infections (8%, n = 5). The most common locations of the ABSSSIs were lower extremity (52%, n = 32), groin or buttock (15%, n = 9), trunk or back (15%, n = 9), and upper extremity (11%, n = 7). Positive wound culture results were available for 26 patients (42%). The most common pathogens isolated were Staphylococcus aureus (61.5%), followed by streptococci (26.5%). Of the S. aureus isolates, 50% were methicillin-resistant S. aureus (MRSA) and 50% were methicillin-susceptible S. aureus (MSSA). Aerobic gram-negative organisms were isolated in 9 patients (35%). Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa were isolated in 5 patients (19%), 3 patients (12%), and 1 patient (3.8%), respectively. A total of 85 recommendations were made to attending physicians for these 62 patients, with an acceptance rate of 95%. For 53 patients (85%), the attending physicians were internists or hospitalists. The most common interventions included dosage changes (44%, n = 27), deescalation (37%, n = 23), antibiotic regimen change (24%, n = 20), and ID consultation (7%, n = 6). Of the 23 de-escalation interventions, 14 (61%) involved changes in antibi-
Am J Health-Syst Pharm—Vol 71 Jul 1, 2014
1137
NOTE Antimicrobial stewardship program
otic regimen from anti-MRSA agent plus a b-lactam to b-lactam monotherapy. The most common of these changes was altering initial therapy with piperacillin–tazobactam plus vancomycin to monotherapy with ampicillin–sulbactam or cefazolin after evaluation. ID consultation recommendations were requested for patients with extensive cellulitis, orbital cellulitis, an infected prosthetic device, or osteomyelitis. When compared with historical data for 1149 patients discharged with an ICD-9 code of 681–682.9, the intervention group had a reduced mean LOS (4.4 days versus 6.2 days, p < 0.001). The 30-day all-cause readmission rate was significantly lower in the intervention group compared with historical data (6.5% versus 16.71%, p = 0.05). However, the 30-day ABSSSI readmission rate did not differ significantly between groups (3.33% versus 6.27% for historical data, p = 0.483). Discussion This study demonstrated that ABSSSIs offer ASPs, in cooperation with primary care clinicians and hospitalists, an opportunity to notably impact outcomes and, consequently, costs. The ASP interventions at our
institution reduced the use of hospital resources (broad-spectrum antibiotic therapy, LOS, and 30-day readmissions) for patients admitted with ABSSSIs. Reducing resource utilization is important for many hospitals, as the rate of hospitalization due to skin and soft-tissue infections has reportedly increased.2 In a matched cohort study, patients hospitalized with ABSSSIs had a longer LOS, higher hospital charges, and greater mortality rates compared with their matched controls without ABSSSIs.3 In the age of cost-effective therapy, it is imperative to evaluate how patients with ABSSSIs are managed. A common recommendation made by the ASP at ACH was to de-escalate therapy from a broad-spectrum antimicrobial regimen (such as piperacillin–tazobactam plus vancomycin) to either cefazolin or ampicillin–sulbactam monotherapy for nonsuppurative cellulitis when there was a high likelihood of Streptococcus species as the etiology and a low likelihood of MRSA based on examination, patient history, and risk factors (e.g., recurrent cellulitis associated with prior lower-extremity surgery, especially if tinea pedis also present). Since the historical data were based on ICD-9 code alone,
Table 1.
Characteristics of the Intervention Group (n = 62) Characteristic Mean age (range), yr Male, no. (%) White, no. (%) Mean Charlson comorbidity index score, with age (range) Surgical intervention, no. (%) Polymicrobial infection, no. (%) Diabetes mellitus, no. (%) Congestive heart failure, no. (%) Peripheral vascular disease, no. (%) Cerebrovascular disease, no. (%) Myocardial infarction, no. (%) Renal disease, no. (%) Malignancy, no. (%)
1138
Value
55.8 (19–90) 33 (53) 58 (94)
3 (0–7) 20 (32) 12 (19) 22 (35) 7 (11) 2 (3) 6 (10) 4 (6) 7 (11) 7 (11)
Am J Health-Syst Pharm—Vol 71 Jul 1, 2014
we were unable to assess exact differences in the amount of antimicrobials used in our intervention patients versus historical controls. However, we feel that the large group of patients whose therapy was de-escalated equates to a notable reduction in antimicrobial use because of ASP intervention. The increased use of b-lactams to treat MRSA and Pseudomonas species as part of empirical therapy in patients with ABSSSIs was recently reported by Berger and colleagues.8 They found that the use of antibiotic therapy to treat MRSA increased from 30% in 2000 to 71% in 2009 (p < 0.01), while antibiotic therapy with an antipseudomonal agent increased from 16% in 2000 to 28% in 2009 (p < 0.01). The changes in empirical antibiotic regimens for patients with ABSSSIs correlate with changes in epidemiology. In the past two decades, community-acquired MRSA has emerged as a major cause of skin and skin structure infections. Several recent studies have found that community-acquired MRSA is the leading cause of skin and soft-tissue infections, with unprecedented levels of such infections in many regions.1,5,9 Furthermore, Jenkins et al.6 found that S. aureus or streptococci were identified in 97% of positive culture results. The most common pathogen was MRSA (44% of patients); however, the use of empirical therapy with broad-spectrum agents covering gram-negative and anaerobe organisms was common practice. In our experience, S. aureus was the most common pathogen encountered, with MRSA and MSSA occurring at equal frequencies. P. aeruginosa was present in only five patients. Although empirical broad-spectrum antibiotic therapy with coverage of MRSA and Pseudomonas species was commonly encountered, we demonstrated that opportunities exist for ASPs to intervene and improve antibiotic use.
NOTE Antimicrobial stewardship program
Our study illustrates how primary care physicians and hospitalists can participate in cooperation with ASPs to improve care of patients with ABSSSIs. As hospitalists assume an increasing role in the care of hospitalized patients, direct involvement or cooperation with an ASP is one way to facilitate this care.10 This study had several limitations. Its retrospective, observational, single-center design was suboptimal. Larger prospective studies involving multiple institutions and randomization are needed to ensure generalizability of the results. Another important limitation was that there was no way to determine the rationale physicians used in selecting the empirical antibiotic regimens for these patients. Further, ACH has a well-established ASP with productive provider relationships that may have been key to the success of the interventions. Finally, since the historical comparison was based on ICD-9 codes alone and not a case–control chart review of the patients admitted to ACH in 2011, confounding
factors that may have accounted for the reduction in LOS cannot be excluded. However, the number of patients represented by the historical data was very large, which may lessen this effect. Conclusion Interventions made by an ASP including a clinical pharmacist were associated with significant reductions in the mean LOS and 30-day all-cause readmission rate for patients with an ABSSSI compared with historical data. References 1. Zervos MJ, Freeman K, Vo L et al. Epidemiology and outcomes of complicated skin and soft-tissue infections in hospitalized patients. J Clin Microbiol. 2012; 50:238-45. 2. Hersh AL, Chambers HF, Maselli JH, Gonzales R. National trends in ambulatory visits and antibiotic prescribing for skin and soft-tissue infections. Arch Intern Med. 2008; 168:1585-91. 3. Hatoum HT, Akhras KS, Lin SJ. The attributable clinical and economic burden of skin and skin structure infections in hospitalized patients: a matched cohort study. Diagn Microbiol Infect Dis. 2009; 64:305-10.
4. Lipsky BA, Weigelt JA, Gupta V et al. Skin, soft-tissue, bone, and joint infections in hospitalized patients: epidemiology and microbiological, clinical, and economic outcomes. Infect Control Hosp Epidemiol. 2007; 28:1290-8. 5. Lipsky BA, Moran GJ, Napolitano LM et al. A prospective, multicenter, observational study of complicated skin and soft tissue infections in hospitalized patients: clinical characteristics, medical treatment, and outcomes. BMC Infect Dis. 2012; 12:227. 6. Jenkins TC, Sabel AL, Sarcone EE et al. Skin and soft-tissue infections requiring hospitalization at an academic medical center: opportunities for antimicrobial stewardship. Clin Infect Dis. 2010; 51:895903. 7. Charlson M, Szatrowski TP, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol. 1994; 47:1245-51. 8. Berger A, Edelsberg J, Oster G et al. Patterns of initial antibiotic therapy for complicated skin and skin structure infections (cSSSI) in US hospitals, 2000-2009. Infect Dis Clin Pract. 2013; 21:159-67. 9. Dukic VM, Lauderdale DS, Wilder J et al. Epidemics of community-associated methicillin-resistant Staphylococcus aureus in the United States: a meta-analysis. PLoS One. 2013; 8:e52722. 10. Rosenberg DJ. Infections, bacterial resistance, and antimicrobial stewardship: the emerging role of hospitalists. J Hosp Med. 2012; 7(suppl 1):S34-43.
Am J Health-Syst Pharm—Vol 71 Jul 1, 2014
1139
NOTE
ar Layar
Impact of an antimicrobial stewardship program on patients with acute bacterial skin and skin structure infections Timothy R. Pasquale, Tamara L. Trienski, Deana E. Olexia, Joseph P. Myers, Michael J. Tan, Anthony K. Leung, Jose E. Poblete, and Thomas M. File Jr.
A
cute bacterial skin and skin structure infections (ABSSSIs) are an increasingly common reason for hospital admissions. 1,2 Such patients are commonly cared for by primary care clinicians and hospitalists. In recent years, hospitals have seen a 71% increase in the rate of hospitalizations due to ABSSSIs.2 Skin and soft-tissue infections are associated with substantial health care costs.1,3,4 In a matched cohort study, Hatoum et al.3 reported that patients with ABSSSIs spent a mean of 3.81 additional days in the hospital and incurred $14,794 in excess hospitalization charges compared with patients admitted without ABSSSIs. In a prospective, multicenter, observational study, Lipsky et al.5 found that patients with ABSSSIs had a mean length of stay (LOS) of 6.0 days. Jenkins and col-
Purpose. The impact of an antimicrobial stewardship program (ASP) on the management of therapy and hospital resources for patients with acute bacterial skin and skin structure infections (ABSSSIs) at a community teaching hospital was evaluated. Methods. A retrospective, observational chart review was performed to evaluate the impact of the ASP on patients admitted to Akron City Hospital with a diagnosis of ABSSSI between February 1 and August 20, 2012. Information on patient demographic characteristics, comorbidities, ABSSSI subtype, antibiotic therapy, microbiology, surgical interventions, and ASP recommendations was collected from medical records and the ASP intervention log. ASP recommendations were organized into five categories: dosage changes, de-escalation, antibiotic regimen change (i.e., change antibiotic regimen to a broad-spectrum antimicrobial or target a pathogen not being covered), infectious diseases (ID) formal consultation, and other.
Timothy R. Pasquale, Pharm.D., M.B.A., is Infectious Disease Clinical Specialist, Carolinas Healthcare System, Carolinas Medical Center, Charlotte, NC. Tamara L. Trienski, Pharm.D., is Clinical Lead Pharmacist, Antimicrobial Stewardship; and Deana E. Olexia, Pharm.D., is Clinical Staff Pharmacist, Summa Health System, Akron City Hospital, Akron, OH. Joseph P. Myers, M.D., is Vice President of Medical Affairs, Southwest Region, Summa Health System, Summa Barberton Hospital, Barberton, OH. Michael J. Tan, M.D., is Infectious Disease Physician; Anthony K. Leung, D.O., is Infectious Disease Physician; Jose E. Poblete, M.D., is Infectious Disease Physician; and Thomas M. File Jr., M.D., is Infectious Disease Physician, Summa Health System, Akron. Address correspondence to Dr. Pasquale (timothy.pasquale@ carolinashealthcare.org). Presented in part at the 50th Annual Meeting of the Infectious Diseases Society of America, San Diego, CA, October 2012.
1136
Am J Health-Syst Pharm—Vol 71 Jul 1, 2014
Results. A total of 62 patients were included in the study. A total of 85 recommendations were made to attending physicians for these 62 patients, with an acceptance rate of 95%. The most common interventions included dosage changes, deescalation, antibiotic regimen change, and ID consultation. When compared with historical data for 1149 patients, the intervention group had a significantly lower mean length of stay (LOS). The 30-day all-cause readmission rate was also significantly lower in the intervention group; however, the 30-day ABSSSI readmission rate did not differ significantly between groups. Conclusion. Interventions made by an ASP including a clinical pharmacist were associated with significant reductions in the mean LOS and 30-day all-cause readmission rate for patients with an ABSSSI compared with historical data. Am J Health-Syst Pharm. 2014; 71:1136-9
Dr. Pasquale has received funding from Forest Pharmaceuticals; has received speaker honorariums from Optimer Pharmaceuticals, Merck, and Cubist Pharmaceuticals; and has served on the pharmacy advisory board for Optimer Pharmaceuticals. Dr. Tan has received speaker honorariums from Cubist, Forest, Optimer, and Pfizer. Dr. Leung has served as a consultant for Merck and Vertex. Dr. File has served on the scientific advisory boards and as a consultant for Astellas, Bayer, Cubist, DaiichiSankyo, Durata, Forest, GlaxoSmithKline, Merck, Pfizer, and Tetraphase. The other authors have declared no potential conflicts of interest. Copyright © 2014, American Society of Health-System Pharmacists, Inc. All rights reserved, 1079-2082/14/0701-1136$06.00. DOI 10.2146/ajhp130677
NOTE Antimicrobial stewardship program
leagues6 concluded that frequent use of potentially unnecessary diagnostic studies, broad-spectrum antibiotic therapy, and prolonged treatment courses was common among adult patients hospitalized with ABSSSIs. Although ABSSSIs are among the most common infections requiring hospitalization, data regarding the use of ABSSSI-related resources and outcomes are lacking. An antimicrobial stewardship program (ASP) has the potential to improve the use of resources and outcomes for patients with ABSSSIs. In order to assess the impact of an ASP on the management of ABSSSIs, we evaluated the LOS and 30-day readmission rate for patients evaluated by the ASP at our community teaching hospital. Background Akron City Hospital (ACH) is a 577-bed, community teaching hospital within Summa Health System, which is a large integrated health care delivery system located in Akron, Ohio. In 2010, ACH initiated a comprehensive ASP. The ASP is led by a clinical pharmacist and an infectious diseases (ID) physician. The pharmacy department pays for 0.5 ID physician full-time equivalent for his or her participation in the ASP. The core antimicrobial stewardship strategy used is prospective audit with feedback. The clinical pharmacist and ID physician round daily, Monday through Friday, to review the identified patients and provide recommendations directly to physicians. Traditional targets of the ASP include patients receiving broad-spectrum antimicrobial therapy and high-cost antimicrobials. On February 1, 2012, an ABSSSItargeted approach to antimicrobial stewardship was incorporated as an additional method for the ASP to reduce costs. In 2011, the mean LOS for patients at ACH with ABSSSIs with an International Classification of Diseases, 9th Revision (ICD-9) codes
of 681–682.9 (cellulitis and abscess of finger and toe or other cellulitis and abscesses) was 6.2 days, and the 30-day ABSSSI readmission rate was 6.2%. The ASP clinical pharmacist identified patients via an emergency department admission list whose chief complaints were consistent with an ABSSSI. Patients without a formal ID consultation on admission were further evaluated by the ASP’s ID physician. The ID physician then reviewed patients’ clinical status and antimicrobial therapy regimen to provide feedback and recommendations to the attending physicians, most frequently a physician from the internal medicine service or a hospitalist. Methods A retrospective, observational chart review was performed to evaluate the impact of the ASP on patients admitted to ACH with a diagnosis of ABSSSI between February 1 and August 20, 2012. Patients were included in the analysis if the ASP intervened and the patient had a discharge ICD-9 code of 681–682.9. Information on patient demographic characteristics, comorbidities, ABSSSI subtype, antibiotic therapy, microbiology, surgical interventions, and ASP recommendations was collected from medical records and the ASP intervention log. ASP recommendations were organized into five categories: dosage changes, de-escalation (i.e., change antibiotic therapy to target a narrow spectrum of antimicrobial activity or decrease the number of antibiotics the patient was prescribed), antibiotic regimen change (i.e., change antibiotic regimen to a broad-spectrum antimicrobial or target a pathogen not being covered), ID formal consultation, and other. Chi-square analysis was performed on the frequency data to compare the intervention group with historical data, which included patients admitted to ACH in 2011 with ICD-9 codes of 681–682.9. The
Summa Health System institutional review board approved this study. Results During the study period, the ASP intervened on the care of 82 patients hospitalized with an ABSSSI. Of these, 62 had a discharge diagnosis consistent with ICD-9 codes 681–682.9 and were included in the analysis. The mean age of patients enrolled in the study was 55.8 years, 33 (53%) were men, 58 (94%) were Caucasian, and their mean Charlson comorbidity index7 score was 3. Other patient characteristics are listed in Table 1. The most common ABSSSI subtypes were cellulitis (76%, n = 47), major or deep abscess (26%, n = 16), and surgical-site infections (8%, n = 5). The most common locations of the ABSSSIs were lower extremity (52%, n = 32), groin or buttock (15%, n = 9), trunk or back (15%, n = 9), and upper extremity (11%, n = 7). Positive wound culture results were available for 26 patients (42%). The most common pathogens isolated were Staphylococcus aureus (61.5%), followed by streptococci (26.5%). Of the S. aureus isolates, 50% were methicillin-resistant S. aureus (MRSA) and 50% were methicillin-susceptible S. aureus (MSSA). Aerobic gram-negative organisms were isolated in 9 patients (35%). Escherichia coli, Proteus mirabilis, and Pseudomonas aeruginosa were isolated in 5 patients (19%), 3 patients (12%), and 1 patient (3.8%), respectively. A total of 85 recommendations were made to attending physicians for these 62 patients, with an acceptance rate of 95%. For 53 patients (85%), the attending physicians were internists or hospitalists. The most common interventions included dosage changes (44%, n = 27), deescalation (37%, n = 23), antibiotic regimen change (24%, n = 20), and ID consultation (7%, n = 6). Of the 23 de-escalation interventions, 14 (61%) involved changes in antibi-
Am J Health-Syst Pharm—Vol 71 Jul 1, 2014
1137
NOTE Antimicrobial stewardship program
otic regimen from anti-MRSA agent plus a b-lactam to b-lactam monotherapy. The most common of these changes was altering initial therapy with piperacillin–tazobactam plus vancomycin to monotherapy with ampicillin–sulbactam or cefazolin after evaluation. ID consultation recommendations were requested for patients with extensive cellulitis, orbital cellulitis, an infected prosthetic device, or osteomyelitis. When compared with historical data for 1149 patients discharged with an ICD-9 code of 681–682.9, the intervention group had a reduced mean LOS (4.4 days versus 6.2 days, p < 0.001). The 30-day all-cause readmission rate was significantly lower in the intervention group compared with historical data (6.5% versus 16.71%, p = 0.05). However, the 30-day ABSSSI readmission rate did not differ significantly between groups (3.33% versus 6.27% for historical data, p = 0.483). Discussion This study demonstrated that ABSSSIs offer ASPs, in cooperation with primary care clinicians and hospitalists, an opportunity to notably impact outcomes and, consequently, costs. The ASP interventions at our
institution reduced the use of hospital resources (broad-spectrum antibiotic therapy, LOS, and 30-day readmissions) for patients admitted with ABSSSIs. Reducing resource utilization is important for many hospitals, as the rate of hospitalization due to skin and soft-tissue infections has reportedly increased.2 In a matched cohort study, patients hospitalized with ABSSSIs had a longer LOS, higher hospital charges, and greater mortality rates compared with their matched controls without ABSSSIs.3 In the age of cost-effective therapy, it is imperative to evaluate how patients with ABSSSIs are managed. A common recommendation made by the ASP at ACH was to de-escalate therapy from a broad-spectrum antimicrobial regimen (such as piperacillin–tazobactam plus vancomycin) to either cefazolin or ampicillin–sulbactam monotherapy for nonsuppurative cellulitis when there was a high likelihood of Streptococcus species as the etiology and a low likelihood of MRSA based on examination, patient history, and risk factors (e.g., recurrent cellulitis associated with prior lower-extremity surgery, especially if tinea pedis also present). Since the historical data were based on ICD-9 code alone,
Table 1.
Characteristics of the Intervention Group (n = 62) Characteristic Mean age (range), yr Male, no. (%) White, no. (%) Mean Charlson comorbidity index score, with age (range) Surgical intervention, no. (%) Polymicrobial infection, no. (%) Diabetes mellitus, no. (%) Congestive heart failure, no. (%) Peripheral vascular disease, no. (%) Cerebrovascular disease, no. (%) Myocardial infarction, no. (%) Renal disease, no. (%) Malignancy, no. (%)
1138
Value
55.8 (19–90) 33 (53) 58 (94)
3 (0–7) 20 (32) 12 (19) 22 (35) 7 (11) 2 (3) 6 (10) 4 (6) 7 (11) 7 (11)
Am J Health-Syst Pharm—Vol 71 Jul 1, 2014
we were unable to assess exact differences in the amount of antimicrobials used in our intervention patients versus historical controls. However, we feel that the large group of patients whose therapy was de-escalated equates to a notable reduction in antimicrobial use because of ASP intervention. The increased use of b-lactams to treat MRSA and Pseudomonas species as part of empirical therapy in patients with ABSSSIs was recently reported by Berger and colleagues.8 They found that the use of antibiotic therapy to treat MRSA increased from 30% in 2000 to 71% in 2009 (p < 0.01), while antibiotic therapy with an antipseudomonal agent increased from 16% in 2000 to 28% in 2009 (p < 0.01). The changes in empirical antibiotic regimens for patients with ABSSSIs correlate with changes in epidemiology. In the past two decades, community-acquired MRSA has emerged as a major cause of skin and skin structure infections. Several recent studies have found that community-acquired MRSA is the leading cause of skin and soft-tissue infections, with unprecedented levels of such infections in many regions.1,5,9 Furthermore, Jenkins et al.6 found that S. aureus or streptococci were identified in 97% of positive culture results. The most common pathogen was MRSA (44% of patients); however, the use of empirical therapy with broad-spectrum agents covering gram-negative and anaerobe organisms was common practice. In our experience, S. aureus was the most common pathogen encountered, with MRSA and MSSA occurring at equal frequencies. P. aeruginosa was present in only five patients. Although empirical broad-spectrum antibiotic therapy with coverage of MRSA and Pseudomonas species was commonly encountered, we demonstrated that opportunities exist for ASPs to intervene and improve antibiotic use.
NOTE Antimicrobial stewardship program
Our study illustrates how primary care physicians and hospitalists can participate in cooperation with ASPs to improve care of patients with ABSSSIs. As hospitalists assume an increasing role in the care of hospitalized patients, direct involvement or cooperation with an ASP is one way to facilitate this care.10 This study had several limitations. Its retrospective, observational, single-center design was suboptimal. Larger prospective studies involving multiple institutions and randomization are needed to ensure generalizability of the results. Another important limitation was that there was no way to determine the rationale physicians used in selecting the empirical antibiotic regimens for these patients. Further, ACH has a well-established ASP with productive provider relationships that may have been key to the success of the interventions. Finally, since the historical comparison was based on ICD-9 codes alone and not a case–control chart review of the patients admitted to ACH in 2011, confounding
factors that may have accounted for the reduction in LOS cannot be excluded. However, the number of patients represented by the historical data was very large, which may lessen this effect. Conclusion Interventions made by an ASP including a clinical pharmacist were associated with significant reductions in the mean LOS and 30-day all-cause readmission rate for patients with an ABSSSI compared with historical data. References 1. Zervos MJ, Freeman K, Vo L et al. Epidemiology and outcomes of complicated skin and soft-tissue infections in hospitalized patients. J Clin Microbiol. 2012; 50:238-45. 2. Hersh AL, Chambers HF, Maselli JH, Gonzales R. National trends in ambulatory visits and antibiotic prescribing for skin and soft-tissue infections. Arch Intern Med. 2008; 168:1585-91. 3. Hatoum HT, Akhras KS, Lin SJ. The attributable clinical and economic burden of skin and skin structure infections in hospitalized patients: a matched cohort study. Diagn Microbiol Infect Dis. 2009; 64:305-10.
4. Lipsky BA, Weigelt JA, Gupta V et al. Skin, soft-tissue, bone, and joint infections in hospitalized patients: epidemiology and microbiological, clinical, and economic outcomes. Infect Control Hosp Epidemiol. 2007; 28:1290-8. 5. Lipsky BA, Moran GJ, Napolitano LM et al. A prospective, multicenter, observational study of complicated skin and soft tissue infections in hospitalized patients: clinical characteristics, medical treatment, and outcomes. BMC Infect Dis. 2012; 12:227. 6. Jenkins TC, Sabel AL, Sarcone EE et al. Skin and soft-tissue infections requiring hospitalization at an academic medical center: opportunities for antimicrobial stewardship. Clin Infect Dis. 2010; 51:895903. 7. Charlson M, Szatrowski TP, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol. 1994; 47:1245-51. 8. Berger A, Edelsberg J, Oster G et al. Patterns of initial antibiotic therapy for complicated skin and skin structure infections (cSSSI) in US hospitals, 2000-2009. Infect Dis Clin Pract. 2013; 21:159-67. 9. Dukic VM, Lauderdale DS, Wilder J et al. Epidemics of community-associated methicillin-resistant Staphylococcus aureus in the United States: a meta-analysis. PLoS One. 2013; 8:e52722. 10. Rosenberg DJ. Infections, bacterial resistance, and antimicrobial stewardship: the emerging role of hospitalists. J Hosp Med. 2012; 7(suppl 1):S34-43.
Am J Health-Syst Pharm—Vol 71 Jul 1, 2014
1139
