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Proceedings of the 56th Annual Convention of the American Association of Equine Practitioners - AAEP December 4-8, 2010 Baltimore, Maryland, USA

Next Meeting : Nov. 18-22, 2011 - San Antonio, Texas, USA

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Review of the Economic Impact of Osteoarthritis and Oral Joint-Health Supplements in Horses Stacey L. Oke, DVM, MSc†; and C. Wayne McIlwraith, BVSc, PhD, DSc, FRCVS, Diplomate ACVS*

Oral joint-health supplements (OJHSs) are a popular adjunct therapy for osteoarthritis, but only 11% of OJHSs are purchased from veterinarians. Considering the safety and quality concerns surrounding OJHSs in conjunction with our current economic position, veterinarians are encouraged to identify, recommend, and sell OJHSs, to osteoarthritis-affected and at-risk horses. Authors’ addresses: Rolling Thunder Scientific, 34 Lasby Lane, Acton, Ontario, Canada L7J 2W9 (Oke); and Gail Holmes Equine Orthopaedic Research Center, Colorado State University, Fort Collins, Colorado 80523 (Mcllwraith); e-mail: [email protected]. *Presenting author; †corresponding author. © 2010 AAEP.

1.

Introduction

Osteoarthritis (OA) is the single most common cause of lameness in horses.1 Indeed, approximately 60% of lameness problems in horses are related to OA.2 The U.S. horse population is currently estimated to be 7.3 million,3 which means that millions of horses currently have this debilitating, performance-limiting musculoskeletal condition. There is no cure for OA. Instead, a multimodal treatment approach is advocated for the management of OA.4 In horses, this multimodal treatment approach could involve the use of one or more of the following: ● ● ● ● ●

non-steroidal anti-inflammatory drugs (NSAIDs), both IV and topical,5a intra-articular corticosteroids,6,7bc intra-articular hyaluronic acid,8 intra-articular (but not IM) polysulfated glycosaminoglycans,8,9d avocado-soybean unsaponifiables (ASU),10

●

interleukin receptor antagonist protein (IRAP I and IRAP II),11 and ● extracorporeal shockwave therapy.9

Dietary modification (omega-3 fatty acids) and nutritional supplements such as glucosamine, chondroitin sulfate, and methylsulfonylmethane (MSM) are also advocated for OA. Although some studies have been performed supporting a select few equine nutritional studies, in general, a dearth of data exists, supporting the use of most commercially available supplements.12e Nonetheless, the high prevalence of OA in combination with the lack of a definitive cure for OA have likely contributed to the popularity of oral jointhealth supplements (OJHSs) among owners, veterinarians, and trainers alike. OJHSs, according to recent market surveys, are the most popular type of nutritional supplement for horses.13 OJHSs account for approximately one-third (34%) of all horse supplement sales (Fig. 1). Over one-half of all pet

NOTES

12

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Proceedings of the Annual Convention of the AAEP – Baltimore, MD, USA, 2010

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Digestion 16%

Hoof 34%

2% 5% 8% 10%

General vitamin/mineral Skin/coat Relaxation

10%

15% Cough/allergy Other

Fig. 1. Equine nutritional supplement sales in the United States based on function.13

supplements sold in the United States are for equine consumption, and 49% of all horse owners purchase and administer some sort of dietary supplement to their horses. In a study of feeding practices in 3-day event horses, the authors found that horses were supplemented with an average of four different oral products daily, including electrolytes, plain salt, and OJHSs.14 Given the high prevalence of OA and horse owners’ documented willingness to purchase OJHSs, the purpose of this review is to relay pertinent information regarding the economic impact of OA and nutritional supplements marketed to support joint health (i.e., OJHSs). The information in this manuscript is anticipated to benefit equine practitioners by providing the necessary tools to select and market quality OJHSs to clients with either OAaffected horses or those at-risk for developing OA. This will not only improve the quality of life of our client’s horses but also improve profitability for veterinary practices. 2.

The Economic Impact of OA

In human medicine, OA is a leading cause of morbidity and one of the top 10 causes of disability worldwide.15,16 The economic impact of OA has been assessed in various studies. In 2005, a Canadian group assessed both direct and indirect costs attributable to OA.15 Direct costs are those paid to the health-care system and out-of-pocket expenditures paid by the patient for prescriptions, medical devices, transportation, and home adaptations. Indirect costs include lost income or leisure time by the patient because of disease and informal care provided by unpaid caregivers for such activities as assistance with personal care and household and yard chores. Of the 1,378 patients included in the study, the average annual cost per patient was approximately $10,000 (U.S. dollars). One-fifth of these costs were attributable to direct costs, whereas the remaining

80% of OA-related costs were indirect. Indirect costs related to OA are, therefore, important and as pointed out by the study authors, must be considered, because failure to incorporate caregiver costs “undervalues the cost of illness.”15 In equine practice, the direct costs of OA include diagnostic and treatment fees charged by veterinarians. Indirect costs include loss of employed or leisure time spent caring for the horse by the owner (or primary caregiver), loss of income of a performance horse when incapable of performance because of OA, and increased work by the owner to care for their horse with OA. If veterinary medicine is similar to human medicine, then the true costs of OA, including both direct and indirect costs, in equine practice can be estimated. For example, if a veterinarian examines a horse for mild to moderate persistent lameness ($50), radiographs two joints ($250), and treats with intra-articular medication ($250), the direct medical costs are approximately $550 (costs estimated using Veterinary Fee Reference17). Additional direct medical costs could include NSAID administration ($20 for an IV dose and $2.50/day for oral administration) and the owner administering an OJHS ($2.00/day). In 1 yr, the direct medical costs could amount to approximately $3,000. If one considers indirect medical expenses, the cost of this horse could be substantially higher—perhaps as high as $15,000/yr. 3.

The Nutritional-Supplement Industry

The veterinary nutritional-supplement industry has grown almost exponentially over the past decade, and market surveys suggest that it will continue to do so until at least 2012. Total retail sales of veterinary nutritional supplements in 2007 exceeded 1.2 billion U.S. dollars and are anticipated to reach almost 2 billion U.S. dollars over the next few years (Fig. 2).13 At present, equine veterinarians benefit little from this windfall, because only 11% of equine dietary supplements are purchased from veterinarians. Instead, most equine supplements are purchased from tack shops/saddleries (32%), online

1800 1600 U.S. Dollars (Millions)

Joint

1400 1200 1000 800 600 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Fig. 2. Actual (2003–2007) and anticipated (2008 –2012) sales of pet supplements in the United States.13 AAEP PROCEEDINGS Ⲑ Vol. 56 Ⲑ 2010

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JOINTS or through mail order (31%), and from feed/seed stores.13 The fact that equine veterinarians are missing a proverbial golden opportunity is not to be taken lightly. According to Andrew Clark18 from Hagyard Equine Medical Institute in Lexington, KY, current economic trends in equine practice are weak. Although Western practices in Texas and Oklahoma have been less affected by the weak economy than English and Thoroughbred practices, the profitability (profit margins) of the average equine practitioner has decreased markedly from approximately 30% to 15% or less.18 In the same 2009 issue of the Veterinary Clinics of North America Equine Edition, Magnus19 pointed out that equine veterinarians are provided few opportunities to develop the necessary business tools during their education to ensure financial success. Considering the continued economic growth of the nutritional-supplement industry combined with the general lack of growth in equine practices in the United States, prudent selection and marketing of high-quality OJHSs for OA are anticipated to benefit not only equine practitioners but also the clients and their horses, given the preponderance of poorquality and potentially detrimental supplements commercially available to unsuspecting consumers. Moreover, OJHSs are not only indicated for horses already diagnosed with OA but also those with a history of trauma, surgery, or navicular disease and prophylactically before any sort of musculoskeletal injury. These indications, contraindications, and relevant safety information are relayed here. 4.

Contraindications

Despite the high lethal dose (LD)50 values associated with many ingredients included in OJHSs, potential contraindications associated with the use of OJHSs do exist and are worth considering when recommending nutritional supplements. Hypersensitivities and gastrointestinal upset after administration are theoretically possible, but no published studies have documented these or other adverse events and specific commercially available OJHSs have been proven safe in horses.26,27 In contrast, drug-herb interactions can and do occur. Yucca (Yucca schidigera) may accelerate NSAID metabolism, ginseng (Panax ginseng, Panax quinquefolius, and Eleutherococcus senticosus) may interfere with drugs that are metabolized by the liver and could potentiate diuretics, flaxseed (Linum usitatissimum) may alter absorption of other drugs, and echinacea (E. purpurea, E. angustifolia, and E. pallida) may interact with drugs metabolized by the liver.28 –32 Poor-Quality Supplements

As described by various research groups, poor-quality supplements are widely available to unsuspecting consumers, including veterinarians.33–37 The preponderance of poor-quality supplements, therefore, makes recommending one or more products a clinical challenge. The term poor product quality refers to supplements that: ● ●

Use, Quality, and Safety of OJHSs

Indications

As previously reviewed by the authors,12 published clinical trials support the use of glucosamine, chondroitin sulfate, and/or ASU in horses with OA20,21 and navicular syndrome22 and post-surgically/posttraumatically.10,23 Evidence in dogs suggests that OJHSs may also be beneficial when administered prophylactically.24 Additional non-subjective, randomized controlled clinical trials evaluating the efficacy of equine OJHSs with adequate power to confirm or refute the clinical indications of these supplements are needed. In the meantime, practitioners are encouraged to take an evidence-based medical approach to assess existing and future in vivo studies. A level-of-evidence rating can be assigned to all clinical trials to concisely and easily evaluate the study’s overall quality and therefore, critically assess the study’s take-home message.25 Wright25 describes studies from Level I (randomized, controlled studies) to Level IV (case series). In general, controlled clinical trials, prospective studies, and randomized studies are superior to non-controlled, retrospective, and non-randomized trials. 14

●

do not contain the type or amount of ingredient listed on the manufacturer-generated product label, recommend or result in administration of subtherapeutic doses of the nutritional supplement(s), and are potentially contaminated by harmful components (e.g., heavy metals or pesticides) or other nutritional supplements because of contaminated equipment during production.

5. Integrating Quality OJHSs into Your Practice: ACCLAIM System

The

Nutritional supplements likely to be safe, effective, and produced in a quality manner can be selected, stocked, and recommended to clients using the seven-step ACCLAIM system (devised by S.L.O.). Virtually all of the information needed to adequately assess an OJHS (or other type of nutritional supplement) can be found on the manufacturer’s product label (Table 1). 6.

Conclusion

Nutritional supplements are extremely popular, and the industry continues to grow despite the downturn in the economy. Although almost one-half of all horse owners purchase and administer nutritional supplements such as OJHSs to their horses, only 11% of all supplements are purchased from veterinarians. The American Association of Equine

2010 Ⲑ Vol. 56 Ⲑ AAEP PROCEEDINGS

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Table 1.

Seven-Step ACCLAIM System for Identifying and Recommending a Qualtiy OJHS

Variable A

A name you recognize?

C

Clinical experience

C

Contents

L

Label claims

A

Administration recommendations

I

Ingredients

M Manufacturer information

Description Is the product in question manufactured by a company you recognize? Products manufactured by established companies that provide educational materials for veterinarians and consumers are preferable to OJHSs manufactured by newly formed companies. Companies who support clinical research and have their products tested in clinical trials for safety, efficacy, and bioavailability with results published in peer-reviewed journals are more likely to have a quality product. These publications should be readily accessible to veterinary practitioners, and companies should be able to provide copies of their published research for your review. Some manufacturers claim to have their product tested but are subsequently unable to provide data or a reprint for evaluation. All active and inactive ingredients and fillers should be indicated on the product label. Products that do not contain the amount of ingredients as listed on the product label likely contain other fillers or ingredients that are not identified and therefore may pose a potential health risk to the horse or the person administering the supplement. If the claims sound too good to be true, they probably are. Supplements with realistic label claims based on scientific study results, rather than testimonials, are preferable. Illegal claims such as those claiming to diagnose, treat, cure, or prevent a disease are abundant. Products with illegal claims should be avoided. The amount of active ingredient administered per dose per day should be easily calculated. A product with some ingredients listed in milligrams and others in ounces but presenting the overall dosing instructions in scoops, without detailing amount of ingredients per scoop, are deliberately confusing. Look for products with clear administration recommendations with the recommended dosages based on published clinical trials. Products with a lot identification number or some other tracking system suggest that some form of pre- and/or post-market surveillance system to ensure product quality is in place. Companies that have voluntarily instituted current Good Manufacturing Practices (cGMPs) and other quality-control/quality-assurance techniques (e.g., tamperresistant packaging and individual tablet/caplet identification) are more likely to be reputable. Producing a supplement akin to a pharmaceutical drug shows a long-term investment into their product and company. Manufacturer information should be clearly stated on the label, preferably in concert with contact information or a website for customer support. Companies employing veterinarians to answer technical questions/issues are preferred.

Practitioners (AAEP) endorses the American Veterinary Medical Association’s (AVMA) 2002 guidelines on the use of complementary or alternative medicine, including the use of nutraceuticals. Specifically, the therapeutic use of micronutrients, macronutrients, and other nutritional supplements is permitted; however, the potential risks and benefits should be discussed within the bounds of a veterinary/client/patient relationship. Because only a small percentage of horse owners purchase OJHSs from their veterinarian, it is likely that a valid veterinary/client/patient relationship exists. Considering the safety and economic impact of nutritional supplements, it behooves the equine practitioner to stock and sell quality OJHSs for their clients’ horses. Acknowledgment

Dr. Stacey Oke is a consultant for Nutramax Laboratories, Inc. Dr. Wayne McIlwraith has no relevant disclosures. References and Footnotes 1. Clegg P, Booth R. Drugs used to treat osteoarthritis in the horse. In Practice 2000;22:594 – 603.

2. Caron JP, Genovese, RL. Principals and practices of joint disease treatment. In: Ross MW, Dyson S, eds. Diagnosis and management of lameness in the horse, 1st ed. Philadelphia, PA: Saunders, 2003:746 –764. 3. American Veterinary Medical Association. United States pet ownership and demographics sourcebook, 2007 ed. Center for Info Management Staff, 2007. 4. Aragon CL, Hofmeister EH, Budberg SC. Systematic review of clinical trials of treatment for osteoarthritis in dogs. J Am Vet Med Assoc 2007;230:514 –521. 5. Frisbie DD, McIlwraith CW, Kawcak CE, et al. Evaluation of topically administered diclofenac liposomal cream for treatment of horses with experimentally induced osteoarthritis. Am J Vet Res 2009;70:210 –215. 6. Foland JW, McIlwraith CW, Trotter GW, et al. Effect of betamethasone and exercise on equine carpal joints with osteochondral fragments. Vet Surg 1994;23:369 –376. 7. Frisbie DD, Kawcak C, Trotter GW, et al. Effects of triamcinolone acetonide on an in vivo equine osteochondral fragment exercise model. Equine Vet J 1997;29:349 –359. 8. Frisbie DD, Kawcak CE, McIlwraith CW, et al. Evaluation of polysulfated glycosaminoglycan or sodium hyaluronan administered intra-articularly for treatment of horses with experimentally induced osteoarthritis. Am J Vet Res 2009;70: 203–209. 9. Frisbie DD, Kawcak CE, McIlwraith CW. Evaluation of the effect of extracorporeal shockwave treatment on experimentally induced osteoarthritis in middle carpal joints of horses. Am J Vet Res 2009;70:449 – 454. AAEP PROCEEDINGS Ⲑ Vol. 56 Ⲑ 2010

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JOINTS 10. Kawcak CE, Frisbie DD, McIlwraith CW, et al. Evaluation of avocado and soybean unsaponifiable extracts for treatment of horses with experimentally induced osteoarthritis. Am J Vet Res 2007;68:598 – 604. 11. Frisbie DD, Kawcak CE, Werpy NM, et al. Clinical, biochemical and histologic effects of intra-articular administration of autologous conditioned serum in horses with experimentally induced osteoarthritis. Am J Vet Res 2007; 462:221–228. 12. Oke SL, McIlwraith CW. Review of the potential indications and contraindications for equine oral joint health supplements, in Proceedings. 54th Annual American Association of Equine Practitioners Convention 2008;261–267. 13. Publishing Division of MarketResearch.com, Inc. Packaged facts. Available online at http://www.packagedfacts.com/ pet-supplments-market-c1641. Accessed on July 14, 2010. 14. Burk AO, Williams CA. Feeding management practices and supplement use in top-level event horses. Comp Exercise Physiol 2008;5:85–93. 15. Gupta A, Hawker GA, Laporte A, et al. The economic burden of disabling hip and knee osteoarthritis (OA) from the perspective of individuals living with this condition. Rheumatology (Oxford) 2005;44:1531–1537. 16. Le Pen C, Reygrobellet C, Gerentes I. Financial cost of osteoarthritis in France the “COART” France study. Joint Bone Spine 2005;72:565–570. 17. Landeck E, ed. Veterinary fee reference, 5th ed. Lakewood, CO; American Animal Hospital Association Press, 2007. 18. Clark AR. Current economic trends in equine practice. Vet Clin North Am [Equine Pract] 2009;25:413– 420. 19. Magnus RP. Marketing your equine practice. Vet Clin North Am [Equine Pract] 2009;25:463– 473. 20. Hanson RR, Smalley LR, Huff GK, et al. Oral treatment with a glucosamine-chondroitin sulfate compound for degenerative joint disease in horses: 25 cases. Equine Pract 1997;19:16 –22. 21. Forsyth RK, Brigden CV, Northrop AJ. Double blind investigation of the effects of oral supplementation of combined glucosamine hydrochloride (HCl) and chondroitin sulfate (CS) on stride characteristics of veteran horses. Equine Vet J Suppl 1996;36:622– 625. 22. Hanson RR, Brawner WR, Blaik MA, et al. Oral treatment with a nutraceutical (Cosequin) for ameliorating signs of navicular syndrome in horses. Vet Ther 2001;2:148 –159. 23. Rodgers MR. Effects of oral glucosamine and chondroitin sulfate supplementation on frequency of intra-articular therapy of the horse tarsus. Intern J Appl Res Vet Med 2006;4: 155–162. 24. Canapp SO, McLaughlin RM Jr., Hoskinson JJ, et al. Scintigraphic evaluation of dogs with acute synovitis after treatment with glucosamine hydrochloride and chondroitin sulfate. Am J Vet Res 1999;60:1552–1557.

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25. Wright JG. A practical guide to assigning levels of evidence. J Bone Joint Surg Am 2007;89:1128 –1130. 26. Kirker-Head CA, Kirker-Head RP. Safety of an oral chondroprotective agent in horses. Vet Ther 2001;2:345–353. 27. Kettenacker RW, Griffin D. Safety profile of an equine joint health supplement containing avocado/soybean unsaponifiables (ASU), glucosamine, chondroitin sulfate and methylsulfonylmethane, in Proceedings. American Academy of Veterinary Pharmacology Therapeutics 15th Biennial Symposia, 2007. 28. Williams CA, Lamprecht ED. Some commonly fed herbs and other functional foods in equine nutrition: a review. Vet J 2008;178:21–31. 29. Miller LG. Herbal medicinals. Selected clinical considerations focusing on known or potential drug-herb interactions. Arch Int Med 1998;158:2200 –2211. 30. Poppenga RH. Risks associated with the use of herbs and other dietary supplements. Vet Clin North Am [Equine Pract] 2001;17:455– 477. 31. Harman J. The toxicology of herbs in equine practice. Clin Tech Equine Pract 2002;1:74 – 80. 32. Izzo AA, Di Carlo G, Borrelli F, et al. Cardiovascular pharmacotherapy and herbal medicines: the risk of drug interaction. Int J Cardiol 2005;98:1–14. 33. Oke S, Aghazadeh-Habashi A, Weese JS, et al. Evaluation of glucosamine levels in commercial equine oral supplements for joints. Equine Vet J 2006;38:93–95. 34. Adebowale AO, Cox DS, Liang Z, et al. Analysis of glucosamine and chondroitin sulfate content in market products and the caco-2 permeability of chondroitin sulfate raw materials. J Am Med Assoc 2000;3:37– 44. 35. Zhou J, Waszkuc T, Mohammed R. Determination of glucosamine in raw materials and dietary supplements containing glucosamine sulfate and/or glucosamine hydrochloride by HPLC with FMOC-Su derivitization: collaborative study. J AOAC Int 2005;88:1048 –1058. 36. Russell AS, Aghazadeh-Habashi A, Jamali F. Active ingredient constituency of commercially available glucosamine sulfate products. J Rheumatol 2002;29:2407–2409. 37. ConsumerLabs.com. Product review: joint health supplements for pets (dogs & cats) and horses with glucosamine, chondroitin, MSM. Available online at www.consumerlab. com/reviews/Joint_Supplements_Glucosamine_Chondroitin_ and_MSM_Dogs_Cats_Horses/jointsupplements_pets/. Accessed on July 14, 2010. a Surpass, Boehringer Ingelheim Vetmedica, Inc., St. Joseph, MO 64506. b Celestone, Schering Corporation, Kenilworth, NJ 07033. c Vetalog, Fort Dodge Animal Health, Fort Dodge, OH 45177. d Adequan, Luitpold Pharmaceuticals, Inc., Shirley, NY 11967. e Oke SL and Mcllwraith CW. Unpublished data, 2008.

2010 Ⲑ Vol. 56 Ⲑ AAEP PROCEEDINGS

Proceedings of the Annual Convention of the AAEP – Baltimore, MD, USA, 2010