Substance use disorders constitute a major global public health problem, attributable largely to their subsequent comorbidity with other health conditions. A new study compared individuals who had previously been hospitalized for a substance use disorder to those who had not to determine the risk of mortality and loss of life among those with 28 different physical health issues.

They discovered that if individuals had been hospitalized for substance use disorder before the onset of the majority of the health disorders, they were more likely than their counterparts to pass away during the research period. People with substance use disorders also had reduced life expectancies than those without substance use disorders for most of the following health problems.

To explore this link further, scientists analyzed patient records from Czech nationwide registers of all-cause hospitalizations and deaths from 1994-2017. By comparing people with a history of substance use disorder hospitalisation to matched counterparts who did not have a substance use disorder but had the same physical health condition, they were able to estimate the risk of death and life years lost after the onset of multiple specific physical health conditions.

Although the study only looked at people living in Czechia, the researchers believe the results are likely similar in other countries, too.

They discovered that the emergence of 26 out of 28 physical health issues increased the likelihood of death during the research among patients with pre-existing substance use disorders compared to their peers. The risk was more than doubled for seven disorders, including atrial fibrillation, hypertension, and ischemic heart disease. People with substance use problems typically have shorter life expectancies than their non-affected peers.

Lead author Tomáš Formánek, a Ph.D. student at the National Institute of Mental Health, Czechia, and the University of Cambridge, said: “Substance use disorders seem to have a profound negative impact on prognosis following the development of various subsequent physical health conditions, in some cases dramatically affecting the life expectancy of the affected people.”

“It is not clear why this should be the case, though there are several possible reasons. It is already known that substance use has a direct negative impact on physical health and is associated with lifestyle factors that affect our health, such as smoking, lack of exercise, and poor diet.”

“Similarly, people with substance use disorders are less likely to participate in screening and prevention programmes for diseases such as cancer and diabetes and are less likely to use preventive medication, such as drugs to prevent hypertension. There are also some factors not directly related to substance use, such as diagnostic overshadowing, meaning the misattribution of physical symptoms to mental disorders. Such misattribution can subsequently contribute to under-diagnosis, late diagnosis, and delayed treatment in affected individuals.”

Senior author Professor Peter Jones from the Department of Psychiatry, University of Cambridge, added: “These results show how important it is not to compartmentalize health conditions into mind, brain or body. All interact, leading to dramatic increases in mortality from subsequent physical illnesses in people with substance use disorders. There are clear implications for preventive action by clinicians, health services, and policy developers that all need to recognize these intersections.”

Co-author Dr. Petr Winkler from the National Institute of Mental Health, Czechia, said: “It is also important to consider that most people with substance use disorders go undetected. They often do not seek professional help, and hospitalizations for these conditions usually come only at very advanced stages of illness. Alongside actions focused on the physical health of people with substance use disorders, we need to equally focus on early detection and early intervention in substance use disorders.”

Journal Reference:

  1. Tomáš Formánek et al. Mortality and life-years lost following subsequent physical comorbidity in people with pre-existing substance use disorders: a national registry-based retrospective cohort study of hospitalised individuals in Czechia. The Lancet Psychiatry; 3 Nov 2022; DOI: 10.1016/S2215-0366(22)00335-2