Pharmacotherapy of Hip Osteoarthritis with Unsaponifiable Soy and Avocado Oil – Insights from the ERADIAS Study

Introduction

Hip osteoarthritis affects approximately 10% of the population aged 65–73 years. Its prevalence dramatically increases with age. Given the aging population, a significant rise in patients suffering from hip and other joint osteoarthritis is expected. Currently, hip total endoprosthesis implantation represents almost 50% of osteoarthritis treatment costs for patients in developed countries.

There is currently no causal therapy for the disease. Unsaponifiable soy and avocado oil is among the commonly used symptomatic drugs categorized as slow-acting drugs in osteoarthritis therapy (SYSADOA). Most published research with positive outcomes has focused on the drug's effect in knee osteoarthritis therapy. The French authors' study evaluated the impact of the drug on symptoms and radiological progression in nearly 400 patients with hip osteoarthritis.

Methodology and Study Course

Patients with primary or idiopathic hip osteoarthritis were included in this prospective, randomized, placebo-controlled, double-blind study with parallel groups. Inclusion criteria included a duration of difficulties ≥ 1 year and a minimum joint space width in the joint of 1–4 mm. Patients were randomized to receive unsaponifiable soy and avocado oil at a dose of 300 mg once daily or placebo. The total therapy duration was 3 years, during which time the medications were administered continuously.

During therapy, the use of nonsteroidal anti-inflammatory drugs was allowed for the necessary period; intra-articular corticosteroid instillations and the use of other SYSADOA drugs, as well as indomethacin, were strictly prohibited.

The primary goal was to evaluate the joint space width at the beginning and after 3 years of therapy. However, during the study, this criterion was questioned due to the asymmetrical distribution of joint space narrowing and the difficulty of monitoring with conventional statistical methods. Therefore, another primary goal was selected: the number of individuals with disease progression ≥ 0.5 mm after 3 years of therapy. Secondary objectives included the evaluation of adverse events during the follow-up and the effect on disease symptoms using parameters such as the Lequesne Index, WOMAC, or VAS score.

Monitored Patient Population

A total of 399 patients were randomized, and a complete analysis was performed on 345 of them (166 in the treatment group, 179 on placebo). The average age of participants was 62.2 years, the average BMI was 27 kg/m², and the average duration of symptoms was 4 years. Women made up the majority of the study population, specifically 54%.

Results 

The initial average joint space width was 2.8 ± 0.9 mm. After 3 years of therapy, no significant difference was noted in the average reduction of joint space width between the treatment group and the placebo group (−0.638 mm vs. −0.672 mm; p = 0.72). However, a statistically significant difference was noted in the number of individuals with reduced joint space progression. In the treatment group, 40.4% of these patients were observed, compared to 50.3% on placebo (p = 0.040). The relative risk of progression reduction was 20% with unsaponifiable soy and avocado oil compared to placebo.

In secondary therapy objectives, including adverse events, no statistically significant differences were observed between active therapy and placebo.

Conclusion

The study results suggest that therapy with unsaponifiable soy and avocado oil may slow the progression of hip osteoarthritis in some individuals. Long-term therapy is safe, with an incidence of adverse events comparable to placebo.

(holi)

Source: Maheu E., Cadet C., Marty M. et al. Randomised, controlled trial of avocado-soybean unsaponifiable (Piascledine) effect on structure modification in hip osteoarthritis: the ERADIAS study. Ann Rheum Dis 2014; 73 (2): 376–384, doi: 10.1136/annrheumdis-2012-202485.