Incidence of skin and soft tissue infections in ambulatory and inpatient settings, 2005-2010.

BACKGROUND: The emergence of community-associated methicillin-resistant S. aureus was associated with dramatically increased skin and soft tissue infection (SSTI) incidence in the first few years of the 21(st) century in the U.S. However, subsequent trends are poorly understood. METHODS: We examined ambulatory and inpatient data of over 48 million persons years aged 0-64 years from the HealthCore Integrated Research Database (HIRD) between 2005 and 2010. Data were extracted from medical, pharmacy, and eligibility databases. We quantified SSTI incidence, type, and complications and comparative incidence trends for urinary tract infections (UTIs) and pneumonia. RESULTS: A total of 2,301,803 SSTIs were identified. Most SSTIs (95 %) were treated in the ambulatory setting and most (60 %) were categorized as abscesses or cellulitis. During the study period, SSTI incidence remained relatively stable from 47.9 (95 % CI: 47.8-48.1) cases/1,000 PY in 2005 to 48.5 cases/1,000 PY (95 % CI: 48.3-48.6) in 2010). Persons aged 45-64 years had the highest incidence of both ambulatory-treated and inpatient-treated SSTIs (51.2 (95 % CI: 51.1-51.3) and 3.87 (95 % CI: 3.84-3.90) cases/1,000 PY, respectively). SSTI complications such as myositis, gangrene, and sepsis occurred in 0.93 % (95 % CI: 0.92-0.94 %) and 16.92 % (95 % CI: 16.87-16.97 %) of ambulatory-treated and inpatient-treated patients, respectively. SSTI incidence was approximately twice that of UTIs and tenfold of that of pneumonia. CONCLUSIONS: Among our large, diverse population of persons less than 65 years, SSTI incidence 2005 through 2010 has remained relatively constant at approximately 4.8 SSTIs per 100 person years, suggesting that previously observed increases in SSTI incidence remain sustained.

Skin and soft tissue infections and associated complications among commercially insured patients aged 0-64 years with and without diabetes in the U.S.

INTRODUCTION: Skin and soft tissue infections (SSTIs) are common infections occurring in ambulatory and inpatient settings. The extent of complications associated with these infections by diabetes status is not well established. METHODS: Using a very large repository database, we examined medical and pharmacy claims of individuals aged 0-64 between 2005 and 2010 enrolled in U.S. health plans. Diabetes, SSTIs, and SSTI-associated complications were identified by ICD-9 codes. SSTIs were stratified by clinical category and setting of initial diagnosis. RESULTS: We identified 2,227,401 SSTI episodes, 10% of which occurred in diabetic individuals. Most SSTIs were initially diagnosed in ambulatory settings independent from diabetes status. Abscess/cellulitis was the more common SSTI group in diabetic and non-diabetic individuals (66% and 59%, respectively). There were differences in the frequencies of SSTI categories between diabetic and non-diabetic individuals (p<0.01). Among SSTIs diagnosed in ambulatory settings, the SSTI-associated complication rate was over five times higher in people with diabetes than in people without diabetes (4.9% vs. 0.8%, p<0.01) and SSTI-associated hospitalizations were 4.9% and 1.1% in patients with and without diabetes, respectively. Among SSTIs diagnosed in the inpatient setting, bacteremia/endocarditis/septicemia/sepsis was the most common associated complication occurring in 25% and 16% of SSTIs in patients with and without diabetes, respectively (p<0.01). CONCLUSIONS: Among persons with SSTIs, we found SSTI-associated complications were five times higher and SSTI-associated hospitalizations were four times higher, in patients with diabetes compared to those without diabetes. SSTI prevention efforts in individuals with diabetes may have significant impact on morbidity and healthcare resource utilization.

Resource use and cost implications of switching among warfarin formulations in atrial fibrillation patients.

BACKGROUND: Despite the uncertainty surrounding the safety of switching warfarin formulations, limited data exist on the resource use and costs associated with this switching pattern. OBJECTIVE: To evaluate health care resource use and costs associated with switching warfarin formulations among patients with atrial fibrillation (AF) in a managed care organization. METHODS: Patients diagnosed with AF (ICD-9 427.31) between July 2004 and August 2008 and who received warfarin therapy were identified in the HealthCore Integrated Research Database and categorized into 3 groups: users of generic warfarin formulations from a single drug manufacturer (generic-only group), users of branded warfarin formulations only (brand-only group), and patients who used generic and branded warfarin therapy interchangeably or who may have used generic drugs from 1 or more manufacturers (generic/brand switching group). Patients were followed 12 months or longer after their index warfarin prescription date to compare all-cause resource use and costs using multivariable regression analysis. RESULTS: The analysis included 12,908 patients: 71.82% were in the genericonly group, 9.61% were in the brand-only group, and 18.57% were in the generic/brand switching group. Patients in the generic/brand switching group were more likely to be hospitalized (relative risk [RR] = 1.43, p < 0.0001) or to use emergency department services (RR = 1.20, p < 0.01), compared to the brand-only users. Hospitalizations were more likely (RR = 1.26, p < 0.001) to occur among generic-only users versus brand-only users. Adjusted mean pharmacy costs per member per month were lower in the generic/brand switching group compared to the brand-only group ($257 vs $273, p = 0.038), but inpatient costs were higher ($1250 vs $972, p < 0.001), resulting in higher ($2125 vs $1847, p < 0.001) total costs. Generic-only users had lower pharmacy costs compared to brand-only users ($246 vs $273, p < 0.001), but total health care costs trended to be higher in the generic-only group ($1957 vs $1847, p = 0.053). CONCLUSIONS: The use of both generic and branded formulations of warfarin interchangeably, or the use of generics from more than 1 manufacturer, was associated with increased use of all-cause health care resources and total costs in patients with AF.