Older adults with schizophrenia are not a homogenous patient population, with various subgroups that differ significantly in terms of comorbid illness and mortality rates and causes, new research shows.
For example, individuals in a group characterized by substance use disorders (SUDs) had a depression prevalence of about 60% and relatively high death rates from unintentional injury and hepatitis.
“The healthcare needs of older adults with schizophrenia can vary widely, so aging persons with schizophrenia can’t be considered a uniform population,” study investigator Alison Hwong, MD, PhD, University of California San Francisco National Clinicians Scholars Program and SF Veterans Administration , told Medscape Medical News.
“For patients with multiple chronic conditions, we need to be proactive in coordinating specialty care. At the same time, we need novel models of person-centered care to help aging adults with schizophrenia live longer, healthier lives,” Hwong added.
The findings were presented at the American Association for Geriatric Psychiatry (AAGP) 2022 Annual Meeting.
Widening Mortality Gap
The life expectancy of patients with schizophrenia is lower by 8-15 years compared with those without schizophrenia and this “mortality gap” has widened in recent years, Hwong noted. Those with schizophrenia also have high rates of healthcare utilization and high direct and indirect health care costs, she added.
Most previous research looking at illness in schizophrenia focused on a single medical condition, “but by midlife, adults with schizophrenia may have multiple medical conditions,” said Hwong. “Little is known about multimorbidity in aging adults with schizophrenia and how that could be related to mortality outcomes.”
The study included 82,858 US veterans aged 50 years and older who had at least one inpatient or two outpatient encounters associated with a diagnosis of schizophrenia in the previous 2 years. The study period ran from 2012-2018.
Using healthcare records and data linkages, researchers examined 20 common medical and psychiatric conditions other than schizophrenia that required medical attention. The investigators used the “latent class analysis,” statistical model to assess differences across classes.
The study included three distinct patient classes: minimal morbidity (43% of the cohort), depression and medical comorbidity (34.2%), and SUDs and related conditions (22.8%).
The SUD group tended to be younger, with a mean age of 57.9 years vs 60.4 years for the minimal comorbidity group and 65.9 years for the depression group.
The SUD group was also less likely to be female (4.8% vs 6.7% and 6%, respectively), less likely to be white, and more likely to be black. This group was also less likely to be married and more likely to have a history of homelessness.
Disease Prevalence Rates
Results showed the morbidity group had minimal rates of less than 10% for all major conditions, except for tobacco dependence, which had a rate of 11.8%.
The depression and medical comorbidity group had very high prevalence rates (more than 20%) for heart attack, congestive heart failure, stroke, cancer, dementia, arthritis, renal disease, sleep disorders, depression, and tobacco dependence. In addition, the rate was 60% for chronic obstructive pulmonary disease.
Participants in the SUD and related conditions group had rates of more than 70% for alcohol use disorder, other drug use disorders, and tobacco dependence. They also had high rates of COPD, hepatitis C, chronic pain, sleep disorders, depression, and posttraumatic stress disorder.
On average, the SUD group was younger and may explain why they were less likely to have heart failure and renal disease, Hwong noted. These results may help inform treatment approaches, she added.
“For the group with largely specific substance use-related conditions, perhaps we can better address their needs with, for example, addiction and infectious disease services instead of a one-size-fits-all model,” said Hwong.
The investigators also examined mortality rates. Those in the depression and morbidity group had the highest rate of overall mortality; 47.5% of this class died during the observation period compared with 27.2% of the SUD group.
More research is needed to understand why the mortality rate is so high in the depression and morbidity group, she said.
High Rates of Accidental Death
The SUD group had the highest rates of death from accidents, possibly from overdoses, suicide, hepatitis C, and alcohol-use related deaths. “Their risks are very specific and appear largely related to substance use,” Hwong noted.
The minimal comorbidity group showed the lowest rates of overall mortality rate (18%) and of cause-specific mortality for most of the included conditions.
Hwong noted she would like to study this class further. “I’m interested to know who are the people with schizophrenia who are thriving and are successfully aging — to learn what is going well for them,” she said.
The researchers also plan to examine the subgroups in more detail to understand differences in treatments, healthcare utilization, and outcomes across groups. They are also interested in assessing other predictors of mortality in addition to multimorbidity.
One limitation of the study is that its cohort consisted of male veterans, so the findings may not be generalizable to other populations. In addition, these were observational data and so the results do not imply causality, Hwong said.
Hwong has reported no relevant financial relationships, but she is supported by the VA and the UCSF National Clinician Scholars Program
American Association for Geriatric Psychiatry (AAGP) 2022 Annual Meeting: Oral Presentation 1. Presented March 20, 2022.
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