What happens to people who inject drugs after surgery for a heart valve infection?

In a Systematic Review and Meta-Analysis published this month in BMC Infectious Diseases the authors discuss rising trends in injectable drug use and the dramatic effects this consumption can have on the outcomes of users undergoing cardiac surgery.

People who inject drugs face many health challenges. Aside from the highly publicized overdose epidemic, people who inject drugs are at risk for several infectious diseases due to the unsterile nature of injecting drugs. These infections range from hepatitis C and HIV to bacterial and fungal infections. Some infections are limited to the skin, like abscesses. Other more serious infections occur when bacteria or fungus penetrate deeper into the blood stream. When these infections get into the blood stream, they have the potential to infect bones, the central nervous system or the heart, among many other sites. When the heart is infected, the heart valves are the main sites that become affected. This condition we term infective endocarditis.

Infective endocarditis is a serious condition with a high likelihood of death or other complications. Examples of these complications include heart failure or embolism – clots that break off the valve and block blood vessels. These clots can block blood vessels in organs such as the kidneys, lungs or brain, leading to death of a part of that organ. The mainstay of treatment are antibiotics and under certain conditions some patients may need surgery.

We estimated that people who inject drugs were 47% more likely to die than people who do not inject drugs.

With the recent increase in the United States and elsewhere of injection drug use and, consequently, infective endocarditis, a debate has unfurled in the mainstream and academic literature investigating what to do when people who inject drugs need surgery for infective endocarditis. This public debate echoes the concerns doctors and surgeons face on a day-to-day basis when dealing with these cases. Health care providers attempt to improve health and therefore try to do everything possible for all patients, however, the recidivism of drug use poses some unique challenges to surgical intervention, even when otherwise medically indicated in this specific set of circumstances. Some providers have chosen to defer or deny surgery even when indicated, although others have proposed strategies that include signed-contracts agreeing to abstinence, multidisciplinary-team treatment approaches, and even a “three-strike rule.”

Many studies from diverse medical centers around the world have provided some evidence of the risks of death and reinfection after surgery in people who inject drugs. A recent study summarized many of these studies in a systematic review and meta-analysis. The authors reported that people who inject drugs have a similar risk of death compared to people who do not inject drugs at 30 days after cardiac surgery for infective endocarditis. In this type of study – meta-analyses – the published results of many studies are pooled using different statistical techniques.

Our objective was to estimate the risk of death and re-operation of people who inject drugs after cardiac surgery for infective endocarditis over a longer period of time. We also performed a systematic review and meta-analysis but extended our analysis to 5 and 10 years. We estimated that people who inject drugs were 47% more likely to die than people who do not inject drugs. We also estimated that people who inject drugs were more than twice as likely to require re-operation over the studied time period. Based on these estimates, at 5 years, people who inject drugs had a 62% chance of being alive compared to a 70% chance in people who do not inject drugs. Further, the average age of people who inject drugs in the included studies was 35 years compared to 51 years in people who do no inject drugs. This is concerning as people who inject drugs were younger, and hence, are less likely to suffer from other chronic diseases, they were still more likely to die.

people who inject drugs were more than twice as likely to require re-operation

We cannot know from the included studies why people who inject drugs were more likely to die or have a re-operation. We do have a major thought as to why and how to prevent it. Traditionally, people who inject drugs rarely receive treatment for their substance use disorders at acute care hospitals. Treatments like methadone, buprenorphine or long-acting naltrexone, exist and have been proven to be effective. The hospital visit is a lost moment when treatment for substance use could be provided but was not. Without treatment for the underlying substance use disorder, people who inject drugs are likely to continue injecting drugs after being discharged from the hospital, in turn, increasing their chance of reinfection and death. The source of the infection has not been addressed. We need to offer treatment to every patient with a substance use disorder at every chance we get.

In conclusion, we provide evidence that people who inject drugs have worse outcomes after cardiac surgery than people who do not inject drugs. Although our data cannot answer the question of whether people who inject drugs should get surgery or not, we do know that interventions are urgently needed to bridge the gap in outcomes after cardiac surgery between people who do and do not inject drugs. Every effort should be made to provide evidence-based therapy for substance use disorders to people with these disorders when engaging medical settings. With the ever-increasing number of people who inject drugs engaging with our medical centers we should be ready to provide these treatments, and further develop strategies to improve on these treatments. This would save the lives of many.

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