Skin and Soft Tissue Infections on the Decline, Yet Still High Among Patients with HIV

Ethan Morgan, PhD

Research published in Clinical Infectious Diseases found that the rate of skin and soft tissue infections (SSTIs) have been on the decline following the previous rise in SSTIs in the early 1990s and 2000s due to methicillin-resistant Staphylococcus aureus (MRSA) infections.

Additionally, researchers of the retrospective study saw that HIV-infected patients are more at risk for SSTIs than the general population. “The higher burden of SSTIs among people living with HIV is likely to impact care for these individuals as it adds further complications to an already burdensome disease,” study researcher Ethan Morgan, PhD, of Northwestern University, told Contagion^®. “Clinicians should be aware of the increased potential for skin infections and advise their patients on how to prevent infection.”

Clinical and administrative data from the Vizient Clinical Data Warehouse on a cohort of patients with primary or secondary SSTIs who visited emergency departments (EDs) in 86 medical centers between 2009 and 2014 (n = 820,441) was used to complete a retrospective analysis of the first ED encounter. Investigators also identified each of the patients’ HIV status using the ICD-9 042 diagnostic code and stratified the patients by the type of payment/insurance used for care (ie, Medicaid/charity/self-paid uninsured [low socioeconomic status], commercial insurance, Medicare, or other).

Using a multivariable regression analysis, the investigators assessed the change in the incidence of SSTIs over time among all patients, the change in SSTI diagnosis among patients with HIV, the comparative SSTI rates among patients with HIV versus those without HIV, and the comparative SSTI rates among patients with comorbidities versus those without comorbidities. Analyses were also stratified by race (ie, African American, Hispanic, and white).

The SSTI-related rate of ED patient encounters observed in the Warehouse database was 31.8 per 1000 ED patient encounters. A total of 47,317 (0.18%) patients in the study cohort had HIV (1.9 per 1000 patient encounters) and, at baseline, patients who were HIV-positive had higher ED encounters for SSTIs compared with patients who were HIV-negative per 1000 individuals (51.9 vs 32.5, respectively).

The investigators observed a significant decrease in the overall SSTI rate from 2009 to 2014 (32.8 per 1000 ED encounters to 29.7 per 1000 ED encounters, respectively; rate ratio [RR] = .98; 95% confidence interval [CI] .98—.98). Reductions in SSTI-related ED encounters were observed more so among adult patients (RR = 0.98; 95% CI. 98–.98), whereas ED encounters increased among children during the 2009 to 2014 time period (RR = 1.005; 95% CI 1.001–1.008). Significant reductions in SSTIs were also found among African American (RR = .97; 95% CI .97–.97), Hispanic (RR = 0.99; 95% CI .98–.99), and white (RR = 0.99; 95% CI .99–.99) patients.

During 2009 through 2014, there were decreases in the SSTI rate among adult patients with comorbidities (RR = .99; 95% CI.99—.995) and without comorbidities (RR = .99; 95% CI .98–.99). Pediatric patients with comorbidities also experienced a decrease in the SSTI rate (RR = .98; 95% CI .97–.99); however, a significant increase in the rate was observed among those without comorbid conditions (RR = 1.01; 95% CI 1.004–1.01).

Significant reductions in SSTI rates were also observed among HIV patients between 2009 and 2014 per 1000 ED patient encounters (54.2 vs 46.3, respectively; RR = .97; 95% CI .94—.99). Higher SSTI rates were observed in HIV patients with commercial insurance (RR = 1.84; 95% CI 1.64–2.07), low socioeconomic status (RR = 1.52; 95% CI 1.44–1.60), Medicare (RR = 1.47; 95% CI 1.34–1.60), and other payer types (RR = 2.23; 95% CI 1.94–2.56).

Regarding study limitations, Dr. Morgan commented, “Given the location of these hospitals, it is possible these trends do not accurately reflect trends in the general population, but instead, reflect trends only in urban environments.” Additional research is needed to overcome the study’s inherent limitations, Dr. Morgan explained, by collecting data from all hospital environments in an effort to improve the generalizability of the findings to the broader US population.