Bromelain as an adjunctive treatment for moderate-to-severe osteoarthritis of the knee: a randomized placebo-controlled pilot study.
BACKGROUND
Osteoarthritis (OA) of the knee is the most prevalent joint disorder. Previous studies suggest that bromelain, a pineapple extract, may be a safer alternative/adjunctive treatment for knee OA than current conventional treatment.


OBJECTIVE
To assess the efficacy of bromelain in treating OA of the knee.


METHODS
Randomized, double-blind placebo-controlled trial.


METHODS
Subjects (n = 47) with a confirmed diagnosis of moderate to severe knee OA were randomized to 12 weeks of bromelain 800 mg/day or placebo, with a 4-week follow-up. Knee (pain, stiffness and function) and quality-of-life symptoms were reported monthly in the WOMAC and SF36 questionnaires, respectively. Adverse events were also recorded. The primary outcome measure was the change in total WOMAC score from baseline to the end of treatment at week 12. Longitudinal models were used to evaluate outcome.


RESULTS
Thirty-one patients completed the trial (14 bromelain, 17 placebo). No statistically significant differences were observed between groups for the primary outcome (coefficient 11.16, p = 0.27, 95%CI -8.86 to 31.18), nor the WOMAC subscales or SF36. Both treatment groups showed clinically relevant improvement in the WOMAC disability subscale only. Adverse events were generally mild in nature.


CONCLUSIONS
This study suggests that bromelain is not efficacious as an adjunctive treatment of moderate to severe OA, but its limitations support the need for a follow-up study.
Brien
S
S
Department of Primary Care, University of Southampton, Southampton, Southampton, UK. sbb@soton.ac.uk
Lewith
G
G
Walker
A F
AF
Middleton
R
R
Prescott
P
P
Bundy
R
R
D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D001963:Bromelains / Q000627:therapeutic use*; D016022:Case-Control Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000188:drug therapy*; D010147:Pain Measurement / Q000379:methods; D010865:Pilot Projects; D016896:Treatment Outcome
D000893:Anti-Inflammatory Agents; D001963:Bromelains