Systematic literature review of economic studies on nature-based social prescribing for health improvement

Nature-based social prescribing (NBSP) is a form of social prescribing that can enhance mental and/or physical health by connecting participants with nature through non-medical community referrals. While evidence suggests potential benefits of NBSP in promoting well-being, its economic impact remains unclear. The purpose of our systematic literature review is to investigate the health-economic impact of NBSP programs. We searched six databases in July 2024. Two reviewers independently screened publications for eligibility: (1) NBSP interventions for health improvement among adults (2), partial or complete economic analyses, and (3) peer-reviewed original studies, published in English, Spanish, or German after the year 2000. Eligible data were systematically extracted by two independent authors into an extraction form including standardized information on the publication, population and setting, compared strategies, details of the analytic framework, main results, limitations, and study conclusions. This information was further synthesized in an evidence table and analyzed using a narrative synthesis approach, with results summarized for each study. The quality of the included studies was assessed using the Consensus Health Economic Criteria list. The review followed PRISMA guideline and is registered on PROSPERO (CRD42021286176). Of the 2,985 hits identified, five studies met the inclusion criteria, all of which were conducted in the United Kingdom (UK) and included people with mild mental and/or physical health issues. The time horizon ranged from twelve weeks to ten years. Three studies conducted a social return on investment (SROI) analysis and reported SROI ratios between 2.6 and 5.1 British pounds (GBP) per GBP invested. One cost-benefit study identified economic returns of 6,000–14,000 GBP per person after one year, with potential returns of up to 8,600 − 24,500 GBP per person after ten years. One cost-utility analysis resulted in costs of 8,600 GBP per quality-adjusted life year gained. Evidence on the health and economic impacts of NBSP is currently limited. The five identified studies, all based in the UK, generally reported favorable health and economic findings. However, the small number of studies, their methodological limitations, and the exclusive UK focus constrain the generalizability of these conclusions. To better inform healthcare decision-making and to implement NBSP programs worldwide, further research on NBSP interventions and their economic impact is needed. Consequently, future studies should explore international settings, incorporate additional data sources, include control groups, and assess longer follow-up periods.