People With Substance Use Disorder are Increasingly Hospitalized for Serious Infections

There is substantial risk of serious infections among people with substance use disorders, particularly those who inject drugs. Yet recent trends for infective endocarditis and other serious infections among people with substance use disorders are understudied.

Results from a new retrospective cohort study published in Clinical Infectious Diseases have confirmed that rates of hospitalization for serious infections among people with substance use disorders are increasing, particularly among young people.

The study was conducted using the Premier Healthcare Database, an electronic health care database from approximately 800 academic and private hospitals, representing about one-fifth of US inpatient discharges.

Investigators identified hospitalizations among patients >18 years from 2012 to 2017 with a primary discharge diagnosis of selected bacterial infections. These serious infections included infective endocarditis, central nervous system abscesses, skin and soft tissue infections, and osteomyelitis. Secondary diagnoses of interest included substance use disorder, viral hepatitis B, C, or D, and HIV.

Annual rates of hospitalization were calculated by dividing the weighted number of hospitalizations by census population estimates for the year.

Investigators also sought to understand whether the microbiology of infections had changed, and therefore examined infective endocarditis hospitalizations where laboratory data was available.

Results indicate that from 2012 to 2017, there were 72,481 weighted admissions with a primary diagnosis of infective endocarditis recorded. Among those, 20,784 (28.7%) included substance use disorder diagnosis.

Overall rates of infective endocarditis and central nervous system abscess related hospitalization have remained stable. In addition, rates of hospitalization linked to skin and soft tissue infection as well as osteomyelitis decreased over time. However, prevalence of hospitalizations with a diagnosis of substance use disorder have increased for all of the infections examined.

The proportion of hospitalizations for infective endocarditis accompanied by a diagnosis of substance use disorder increased from 19.9% to 39.4% P <.0001).

Prevalence of substance use disorder among the 242,651 osteomyelitis hospitalizations increased from 8.2% to 16.6% (P <.0001).

Among the 48,742 central nervous system abscess admissions, substance use disorder prevalence increased from 15.4% in 2012 to 23.8% in 2017 (P <.0001). Among patients hospitalized for skin and soft tissue infections, prevalence of substance use disorder increased from 6.8% to 9.4% (P <.0001).

Discharge codes recorded specific substance use for some patients, with the following categories (which are not mutually exclusive.) Among all infection diagnoses accompanied by substance use disorder, 58.6% had >1 discharge diagnosis code related to opioids, 40.8% related to cocaine, 18% related to amphetamines, and 0.2% related to hallucinogens. Another 55.1% of discharge codes related to other drugs or to unspecified drug use.

Among infective endocarditis, osteomyelitis, and central nervous system abscess hospitalizations, the percentage of patients aged 18-44 years increased over the study period.

In particular, the estimated rate of combination infective endocarditis and substance use disorder hospitalizations more than doubled from 1.6 to 3.6 per 100,000 people.

Microbiological examination found that Staphylococcus aureus and Viridans streptococci were the most common pathogens for patients with infective endocarditis who were also diagnosed with substance use disorder. Study authors suggest that increasing emphasis on strategies caused by accidental injection of flora from the skin and mouth could be beneficial in preventing endocarditis.

“These data highlight an important correlate of the ongoing opioid crisis and indicate the threat posed to recent progress in reducing the impact of invasive bacterial diseases such as S. aureus infection. Interventions and health communications aimed at reducing the risk of bacterial infections as a complication of substance misuse should be added to preventive care for persons with SUD [substance use disorder],” authors of the retrospective study authors wrote.

A recent article concerning clinical strategies for opioid related infections and treatment of underlying substance use disorders was written specifically for infectious disease clinicians, and could be a useful tool for clinicians in light of the challenges health systems are facing. It is clear more must be done to reduce risk of infection and address the underlying social determinants of substance use disorder.