Does depression in older medical inpatients predict mortality?

Area of Science:

• Geriatric Medicine
• Psychiatry
• Epidemiology

Background:

• Previous research on depression's impact on older medical patients' mortality shows conflicting findings.
• This study addresses inconsistencies by examining current depression diagnosis and prior depression history.
• Potential biases from sample selection and confounding factors were considered.

Purpose of the Study:

• To investigate the association between depression (current diagnosis and history) and mortality in elderly medical inpatients.
• To clarify the inconsistent findings in prior research.
• To control for confounding variables like physical illness and cognitive status.

Main Methods:

• Recruited 500 medical inpatients aged 65+ with mild cognitive impairment from two Montreal hospitals.
• Screened for depression using Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria.
• Utilized Cox proportional hazards models to analyze survival over 16–52 months, adjusting for baseline data including physical illness, comorbidity, and service utilization.

Main Results:

• 116 patients (23.2%) had a history of depression.
• Patients with both current major depression and a history of depression exhibited significantly lower mortality (hazard ratio 0.42; 95% CI: 0.25, 0.70) after adjustments.
• No significant mortality difference was found for patients with only a current depression diagnosis or only a history of depression.

Conclusions:

• In older medical inpatients without a history of depression, a current diagnosis did not impact mortality after adjusting for confounders.
• A combination of coincident major depression and a history of depression was associated with reduced mortality.
• Depression's complex relationship with mortality in older adults warrants further investigation, considering diagnostic status and history.