Symptom-modifying effects of oral avocado/soybean unsaponifiables in routine treatment of knee osteoarthritis in Poland. An open, prospective observational study of patients adherent to a 6-month treatment

OBJECTIVES: Observational studies provide insights into real-life situations. Therefore, we assessed the effects of oral avocado/soybean unsaponifiable (ASU) capsules on pain relief and functional ability in patients, while they were receiving a routine treatment for knee osteoarthritis (OA). MATERIAL AND METHODS: An open, prospective, observational 6-month study was conducted in 99 centers in Poland in a group of 4822 patients with symptomatic knee OA receiving one 300 mg ASU capsule/day as a routine medication. The patients had no diagnoses of other rheumatic diseases and were not treated with other symptomatic slow-acting drugs for osteoarthritis (SYSADOAs). Data on OA symptoms and therapy were collected from the initiation of ASU treatment (visit 0) and during 3 consecutive control visits performed every 2 months (visits 1–3). Functional Lequesne index, severity of joint pain of one symptomatic knee (Laitinen index and VAS), use of analgesics and non-steroidal anti-inflammatory drugs (NSAIDs), adherence to treatment and adverse events were evaluated and recorded using electronic Case Report Forms. RESULTS: Four thousand one hundred and eighty-six patients (86.8%) attended all 4 visits. In 94.2% of patients (mean age 60.7 ±11.6 years SD, 73.4% female) at least one OA risk factor was identified. There was a significant improvement in functional ability between the last and baseline visits as evidenced by the median Lequesne index decreasing from 8 to 4 points (p < 0.001). Measures of pain intensity also fell significantly (p < 0.001) throughout the study: median Laitinen score decreased from 6 to 3 points, median pain at rest VAS – from 1.8 to 0 cm and median pain during walking VAS – from 5.6 to 1.9 cm. The significant differences were also noted between consecutive visits. The proportion of patients using analgesics and NSAIDs declined from 58.8% at the baseline visit to 24.9% at the last visit 3 (p < 0.001). Defined daily dose of NSAIDs decreased significantly from 1 at the baseline visit to 0.67 at the visit 3. Severe adverse events associated with ASU treatment were not observed. CONCLUSIONS: It was the first observational study in Poland evaluating the effects of routine knee OA treatment with oral ASU. Only a small group of patients (13.2%) treated with ASU discontinued the study. The majority of patients adherent to the ASU treatment for 6 months showed gradual alleviation of joint pain, improvement in functional ability and a significant reduction in NSAIDs intake.