Aim: Our study aims to assess the effectiveness of horticultural therapy in improving outcomes in older patients with dementia.

Design: A systematic review and meta-analysis.

Methods: The included studies comprised randomised controlled trials (RCTs) that aimed to assess the effectiveness of horticultural therapy on cognitive function in older patients with dementia. The study design and data extraction were independently conducted by two investigators, who also evaluated the risk of bias using RoB 2.0. The meta-analysis was carried out using Stata 15.1 software.

Data sources: On November 2023, we searched relevant English and Chinese publications in PubMed, Web of Science, Cochrane Library, Embase, CNKI and Wanfang databases.

Results: The meta-analysis included a total of 9 RCTs, involving 655 older patients diagnosed with dementia. The findings from these studies demonstrated that horticultural therapy had a significant positive impact on various aspects of the patients' well-being when compared to conventional care. Specifically, it was found to improve cognitive function scores, alleviate symptoms of depression, enhance daily activities and enhance overall quality of life. When conducting a subgroup analysis, it was observed that horticultural therapy had a statistically significant effect on cognitive function in older patients with dementia when the intervention frequency was at least two times per week. Furthermore, interventions with a duration of less than 6 months were found to be more effective than those lasting 6 months or longer. Additionally, outdoor horticultural therapy was found to be superior to indoor interventions. Moreover, structured interventions were observed to yield better outcomes compared to non-structured interventions.

Conclusion: More high-quality studies are needed to further corroborate these findings due to the low quality of the included studies. Horticultural therapy has been found to have a significantly positive impact on the cognitive function, depression status, ADL, and quality of life of older patients with dementia. IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE: We provide references for non-pharmacologic treatment of older patients with dementia. WHAT PROBLEM DID THE STUDY ADDRESS?: This study aimed to measure the efficacy of horticultural therapy in older patients with dementia across four dimensions: cognitive function, depression levels, daily living activities and overall quality of life. WHAT WERE THE MAIN FINDINGS?: In older patients with dementia, horticultural therapy has been proven to have a significant positive impact on cognitive function, depressive status, activities of daily living and quality of life. WHERE AND ON WHOM WILL THE RESEARCH HAVE AN IMPACT?: This study will inform non-pharmacological interventions for older patients with dementia worldwide.

Patient or public contribution: No Patient or Public Contribution.