A Systematic Review of Complementary and Alternative Veterinary Medicine: Miscellaneous Therapies
Bergh A, Lund I, Boström A, Hyytiäinen H, Asplund K (2021) · Animals · n=42
RCT evidence detailTrial reference
Study Profile
- Design
- PRISMA-compliant systematic review of complementary and alternative veterinary medicine (CAVM) therapies including leech therapy (hirudotherapy) in cats, dogs, and horses; Web of Science / CABI / PubMed search (Swedish University of Agricultural Sciences, Karolinska, University of Helsinki, Umeå University)
- Sample size (n)
- 42
- Intervention
- Veterinary leech therapy (hirudotherapy) examined among 24 CAVM modalities for cats, dogs, and horses; 42 studies eligible across all CAVM modalities, of which 9 categories had any evidence including leech therapy
- Comparator
- Standard veterinary care or untreated control (across heterogeneous included trials)
- Primary endpoint
- Strength of clinical evidence for each CAVM therapy in companion animals and horses
- Primary result
- 42 studies across nine identified CAVM modalities (aromatherapy, gold therapy, homeopathy, hirudotherapy, mesotherapy, mud, neural therapy, sound/music therapy, vibration therapy); 15 of 24 predefined therapies had no studies; bias risk high in 17 studies, moderate-to-high in 10, moderate in 10, low-to-moderate in 4, low in 1; even among lower-bias studies, considerable heterogeneity in treatment effects; authors conclude scientific evidence insufficient to define clinical efficacy of the reviewed CAVM therapies including leech therapy
- Follow-up duration
- Variable across included studies
- PMID
- 34944133
Key Findings
- First multi-modal systematic review including veterinary hirudotherapy in cats/dogs/horses
- High overall risk of bias across included veterinary CAVM studies
- Veterinary leech-therapy clinical evidence base remains thin
- Authors call for higher-quality veterinary RCTs
- Important context for cross-species ASH safety and ethics literature
Limitations
- Mixed indication and species — no condition-specific synthesis
- High bias-risk dominates the underlying veterinary studies
- Pre-2021 literature only — may miss recent veterinary case series
- English-language search may have missed veterinary literature in other languages
- Authors do not separate leech-specific evidence from other CAVM modalities
Clinical Implications
Bergh 2021 confirms that veterinary hirudotherapy remains an under-evidenced practice area. For ASH's broader scientific scope, the review provides cross-species context (alongside Trenholme 2021 leech-induced airway obstruction veterinary case) and reinforces the need for higher-quality veterinary trials before clinical recommendations can be extended to companion-animal or equine practice. No US K040187 device-clinical-practice implications.
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