Metabolic syndrome (MetS) in older adults with depression is associated with greater chronicity and more severe depressive symptoms, which might account for poor antidepressant response, according to a study published in the Journal of the American Geriatric Society.
The Incomplete Response in Late Life Depression: Getting to Remission (IRL Grey) study (ClinicalTrials.gov identifier NCT00892047) was conducted to “better inform therapy for treatment-resistant depression in older adults,” the authors state.
The researchers studied 435 adults age 60 years and older (mean age; 69.1) with major depressive disorder who were treated with extended-release venlafaxine for ≥12 weeks. Of these, 51% (n=222) of participants met criteria for MetS at baseline.
Symptom severity was measured by the Montgomery-Åsberg Depression Rating Scale, with remission defined as a score of ≤10 at the last 2 visits.
Participants with MetS had greater symptom severity and chronicity of depression at baseline, and the majority (59.1%) had been treated previously with an antidepressant medication.
Remission was achieved in 41.8% of participants, with less likelihood of remission in individuals with MetS, compared with those without (36.9% vs 46.5%; chi-square=4.03; degrees of freedom=1; P =.04).
In the unadjusted analysis, MetS was associated with prolonged time to remission (hazard ratio [HR]: 0.71; 95% CI, 0.52-0.95). However, an adjusted model identified female sex and no adequate prior antidepressant trial during the episode as predicting decreased time to remission, whereas duration of depressive episode and greater baseline Montgomery-Åsberg Depression Rating Scale score predicted longer time to remission.
When these variables were taken into account, MetS was no longer significant as a predictor of time to remission (HR: 0.86; 95% CI, 0.64-1.16).
Higher high-density lipoprotein cholesterol level predicted shorter time to remission, and higher diastolic blood pressure and more MetS components predicted greater time to remission. However, in the adjusted model, only diastolic blood pressure (HR: 0.87/10-mm Hg increase; 95% CI, 0.77-0.99) remained a significant predictor.
The researchers warned that their results should be “interpreted with caution” and that clinicians should not currently “treat older adults with depression differently in the face of co-occurring MetS.”
Nevertheless, the findings suggest that the association between higher diastolic blood pressure and poorer antidepressant response, “bears further examination and replication.”
Mulvahill JS, Nicol GE, Dixon D, et al. Effect of metabolic syndrome on late-life depression: associations with disease severity and treatment resistance. J Am Geriatr Soc. 2017;65(12):2651-2658.