Animal-assisted interventions for depression in older adults: an umbrella review with meta-analysis and trial sequential analysis.

BACKGROUND

Depression affects up to 30% of older adults and is associated with increased morbidity and mortality. Animal-assisted interventions (AAIs) - usually known as "pet therapy" - have emerged as promising complementary approaches, yet evidence synthesis remains fragmented.

OBJECTIVE

To comprehensively evaluate the effectiveness of AAI in reducing depressive symptoms among older adults through an umbrella review of systematic reviews and meta-analyses, incorporating trial sequential analysis.

METHODS

We systematically searched PubMed, Embase, and Cochrane Library through September 2025 for systematic reviews and meta-analyses examining AAIs for depression in older adults. Quality assessment was performed using AMSTAR-2. We calculated the Corrected Covered Area to assess overlap between meta-analyses, re-analyzed primary study data to avoid double-counting, and conducted trial sequential analysis to evaluate evidence sufficiency.

RESULTS

Five systematic reviews encompassing 27 unique primary studies with 2,156 participants were included. The pooled random-effects meta-analysis demonstrated a significant reduction in depressive symptoms (SMD = 0.73; 95% CI: 0.57-0.89; p < 0.001) with moderate heterogeneity (I² = 43.4%). Trial sequential analysis revealed that the cumulative Z-curve crossed monitoring boundaries at 75% of the required information size, confirming evidence sufficiency. The Corrected Covered Area was 20.4%, indicating moderate overlap between meta-analyses.

CONCLUSIONS

AAIs are associated with clinically meaningful reductions in depressive symptoms among older adults. Trial sequential analysis confirms that sufficient evidence exists to support this conclusion. AAIs represent a valuable, low-risk, patient-centered complement to conventional depression treatments in geriatric care. PROSPERO REGISTRATION: [CRD420251250448].