Depression in Older Adults Increases Mortality Risk

Depressed mood in adults 50 years and older is associated with a more than 2-fold increased risk for mortality after adjusting for possible confounding factors, according to a 12-year prospective naturalistic study.

Helen Lavretsky, MD, David Geffen School of Medicine at UCLA, Los Angeles, California, and multicentre colleagues found that older adults who had both subcortical lacunes on magnetic resonance imaging (MRI) and depressed mood had the shortest survival among the cognitive groups assessed, whereas adjusted analyses showed depressed mood was associated with more than twice the mortality risk.

The study was published online February 16 in the American Journal of Psychiatry.

"The cohort we studied was very well characterized — all participants had an MRI and detailed physical and behavioral examination — and included subjects with dementia or cognitive impairment and cognitively healthy controls. All relevant factors were controlled for in the analysis, and depressed mood was associated with a higher mortality risk," Dr. Lavretsky told Medscape Psychiatry, “

Longitudinal Study

A total of 498 participants, mean age at baseline of 74.5 years, were recruited from the Ischemic Vascular Dementia Program Project, a multicenter, longitudinal study examining the contribution of subcortical ischemic vascular disease to cognitive impairment and dementia.

All subjects underwent a comprehensive clinical evaluation that included a detailed medical and neurologic history and examination, laboratory workup, and neuropsychiatric assessment of behavioral and psychological symptoms.

In particular, depressed mood, anhedonia, anergia, and apathy were assessed using a structured behavioral assessment. Cognition was also evaluated using a battery of neuropsychological tests, and all subjects underwent a research protocol MRI.

At baseline, 36% of the patients were cognitively intact, 31% were cognitively impaired without dementia, and 33% were diagnosed as having dementia. Subcortical lacunes were also identified on MRI in 41% of the group overall. Of the total cohort, 35% died during the follow-up, with a median survival time of 5.6 years.

Results from the multivariate Cox regression analysis indicated that summary measures of total neuropsychiatric symptoms, depressed mood, and anergia each remained significantly associated with mortality after adjustment for cognitive status, age, male sex, education level, and race. "Except for a decrease in the anergia hazard ratio, further adjustment for the presence of lacunes did not alter these results," the study authors add.

Even when demographic characteristics, the presence of lacunes and all comorbid vascular conditions were taken into account, "the summary measure of total neuropsychiatric symptoms and depressed mood remained significantly positively associated with mortality," the investigators state. In fact, in this particular cohort, depressed mood increased the risk of dying on average by between 90% and 120%, whereas anergia and global measures of neuropsychiatric symptoms increased the risk of dying on average by 30% to 80%, the investigators point out.

Apathy or anhedonia also increased the risk of dying but not significantly so.

Worse Outcomes

According to the investigators, depression may lead to worse outcomes for a number of reasons. “First, there may be some direct biological effects, as suggested in cardiovascular data, such as exaggerated platelet aggregation and reduced heart rate variability," they write. Depression may also deter patients from bothering with medical care, or it may lead to behaviors that discourage caregivers from providing the necessary assistance.

Cognitive symptoms may also affect how patients perceive their situation, further increasing depressive symptoms. Depressed, inactive, withdrawn patients may also be susceptible to unexpected complications, such as poor long-term outcomes associated with diabetes.

"High levels of attention should be given to screening for depression in those patients who demonstrate microvascular disease on structural MRI or CT [computed tomographic] scans, and aggressive treatment should be directed against both vascular risk factors, such as hyperlipidemia, hypertension, and diabetes, and depressive symptoms to reduce the risk of mortality," the study authors write.

The study was supported by the National Institute on Aging, the California Department of Health Services AD Program, and the National Institutes of Health. Dr. Lavretsky has received research support from Forest Research Institute, the National Institutes of Health, and the National Institute of Mental Health.

Am J Psychiatry. Published online February 16, 2010.

-From: “ Depression in Older Adults Increases Mortality Risk” by Pam Harrison, Medscape Psychiatry, February 26, 2010, http://www.medscape.com/viewarticle/717663 retrieved 3/1/10.

3/10