Conditions: Osteoarthritis, Knee Osteoarthritis, Hip
Keywords: double blind randomised controlled trial phase II Devil's Claw osteoarthritis of the knee osteoarthritis of the hip
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 67
Healthy volunteers: no

Brief summary:
Osteoarthritis of both the knee and hip joints are common conditions; knee osteoarthritis affects 6% of adults over 30 years of age and osteoarthritis of the hip affects between 3% and 6% of the Caucasian population. Both forms of osteoarthritis are associated with disability. Conventional treatment (analgesics and the use non-steroidal anti-inflammatory, NSAIDS) is prophylactic, aimed at decreasing pain and improving function. However long term use of NSAIDS is associated with a high incidence of adverse events (gastrointestinal tract symptoms). A safer alternative treatment would therefore be beneficial.

Both anecdotal evidence and recent studies have implicated the potential of the herbal remedy Devil's Claw (Harpagophytum procumbens) for the treatment of painful, chronic arthritic type conditions (Ernst and Chrubasik, 2000). Devil's Claw is an extract obtained from the root of the Harpagophytum procumbens plant, a member of the sesame family found in the Kalahari region in South Africa. It has been shown that this herbal remedy has anti-inflammatory and analgesic effects (Baghdikian et al, 1997). Currently Devil's Claw is marketed for use as a supportive treatment of degenerative arthrosis, is not a Medicines Control Agency licensed product and is freely available to the general public in health food stores and pharmacies.

The objectives of this study are to assess the efficacy, optimum dosage and safety of the herbal remedy Devil's Claw (Harpagophytum) in the treatment of osteoarthritis of the knee and/or hip. The primary objective of this study is to investigate the following three principal questions:

1. To compare the efficacy of Devil's Claw with placebo in the treatment of osteoarthritis of the knee and/or hip
2. To determine the optimum dose of Devil's Claw and
3. To evaluate the safety and tolerability of three doses of Devil's Claw in the treatment of osteoarthritis of the knee/hip and to compare them to placebo There are also a number of secondary research objectives that will also be addressed (see later).

These objectives are based on the following hypotheses :

Hypotheses

* Devil's Claw has anti-inflammatory properties (as assessed by the reduction in pain, stiffness and disability aspects on the WOMAC) in chronic osteoarthritis of the knee and/or hip after 16 weeks of treatment, as compared to placebo.
* A dose response effect exists in the treatment of osteoarthritis of the knee/hip by Devil's Claw.

Detailed description:
STUDY DESIGN: Randomized, placebo-controlled, dose-ranging two-centre study PREPARATIONS FOR INVESTIGATION: Devil's Claw (Allya®)/placebo as tablets

STATISTICAL METHODS:

Analysis on an intention to treat basis.

The following tests will be performed and all statistical significance will be set at p \< 0.05:

Primary efficacy analysis: The primary outcome will be the reduction in WOMAC total score from baseline to week 16. The week 16 means for the four treatment groups will be compared using an analysis of covariance taking account of baseline assessments and any demographic differences, age, gender, etc, which are found to be significant. Multiple comparison tests will be used to examine specific differences of initially specified interest, such as the two highest doses of Devil's Claw versus placebo.

Secondary Efficacy Analysis: Similar analyses of covariance will be used to examine treatment group differences at week 16 compared with baseline for WOMAC subscales (pain, stiffness and physical function), and Quality of Life assessments (SF-36). Changes in the subject's well-being and overall global assessment will be compared using appropriate non-parametric tests, e.g. Mann-Whitney test or MacNemar's test. Changes in attitudes and health beliefs to CAM will be assessed using Chi-Squared tests.

Safety Evaluation: Group differences between adverse event reporting will be assessed by descriptive methods.

NUMBER OF PATIENTS:

264 (50 patients in each group, with an expected total of 64 drop-outs) NUMBER OF SITES: 2

TIME SCHEDULE:

Study Start: April 2004 Study End: March 2007 Observation period/patient: 20 weeks

Arms:
arm 1: Sub clinical dose if the 3 doses employed arm 2: Active dose arm 3: Active dose arm 4: Comparator for all active intervention arms

Interventions: intervention 1: Devil Claw intervention 2: Placebo
Intervention descriptions: intervention 1: Dose ranging study so will elucidate dose Frequency is four times daily intervention 2: Placebo has same dosing freq as for active intervention and for same time period

Protocol document: