People who use drugs have double the rate of readmission for S. aureus
People who use drugs experienced double the rate of hospital readmission and lower rates of antibiotic completion for invasive Staphylococcus aureus infections than their non-drug-using peers, according to a study.
“As a first-year infectious diseases fellow, I saw countless cases of S. aureus bacteremia and other invasive infections. Patients often fell into two epidemiologic groups older, chronically ill patients with hospital-acquired infection vs. healthier patients who used drugs often contending with considerable social challenges,” Ayesha A. Appa, MD, an infectious diseases and addiction medicine fellow at University of California, San Francisco (UCSF), and Zuckerberg San Francisco General, told Healio.
“I worried that ID recommendations about optimal treatment may not be working as well for the latter group, that systems are not set up for persons who use drugs (PWUD) to succeed,” Appa said. “So, we assembled 5 years of S. aureus infections at UCSF to compare outcomes in these two groups of patients.”
Appa and colleagues identified adults hospitalized between 2013 and 2018 at two medical centers in San Francisco who had S. aureus bacteremia or ICD-coded diagnoses of endocarditis, epidural abscess or vertebral osteomyelitis with compatible culture. According to the study, in addition to comparing demographic and clinical characteristics, the researchers constructed models for 1-year infection-related readmission and mortality, adjusted for age, race/ethnicity, housing, comorbidities and MRSA.
The study included 963 hospitalizations for S. aureus infections among 946 patients. Of them, 372 (39%) occurred in PWUD. Among these PWUD, heroin (198, 53%) and methamphetamine use (185, 50%) were common.
Overall, the researchers found that PWUD had a lower rate of antibiotic completion compared with non-PWUD (70% vs. 87%; P < .001), that drug use was not associated with increased mortality, and that the 1-year readmission rate for ongoing or recurrent infection was double in PWUD compared with non-PWUD (28% vs. 14%; adjusted HR = 2; 95% CI, 1.3-2.9).
The study also showed that MRSA was independently associated with 1-year readmission for infection (aHR = 1.5; 95% CI, 1.1-2.2), Appa and colleagues reported.
“PWUD with severe S. aureus infections should be receiving more effective, patient-centered treatment, and we need to develop more models of care that pair substance use disorder and infection treatment,” Appa said.
She agrees with other experts that there should be a new ID subspecialty covering addiction moving forward.
“As we found in our study, almost 40% of these invasive S. aureus infections were among persons who use drugs, and even when there are excellent, life-saving medications to manage opioid withdrawal or use disorder, these were being underutilized,” Appa said. “However, it’s not just about medications both ID and addiction medicine physicians love the patient’s story, understanding their social context and advocacy so it’s really a great fit.”