Fish Oil in Knee Osteoarthritis: A Randomised Clinical Trial

Running head: RESEARCH AND EVIDENCE
Critical appraisal
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1RESEARCH AND EVIDENCE
Article
Hill, C. L., March, L. M., Aitken, D., Lester, S. E., Battersby, R., Hynes, K., ... & Jones, G.
(2015). Fish oil in knee osteoarthritis: a randomised clinical trial of low dose versus high
dose. Annals of the rheumatic diseases, annrheumdis-2014, 75, 23–29.
Section 1
The study was about carrying out a research to investigate the effects of high-dose
fish oil over low-dose supplements for certain structural and symptomatic outcomes related to
knee osteoarthritis. Osteosrthritis is one of the most common forms of arthritis that affects
more than a million people on a global scale and refers to a condition that involves
inflammation of the joints due to cartilage degeneration (Berenbaum, 2013). While several
studies had earlier established the efficacy of fish oil for reducing osteoarthritic symptoms,
most of these studies had been conducted on animals, and not on patients (Boe & Vangsness,
2015). Thus, this RCT tested whether low-dose of fish oil had any benefits for the same.
The aim of the study was concerned with drawing a comparison between the anti-
inflammatory doses of fish oil with its low dose, which in turn is not considered to be anti-
inflammatory in nature. Fish oil acts as one of the best sources of omega-three fatty acids that
are required for proper functioning of the human body. An association has been established
with joint health and omega-3 fatty acids. The Research question can be defined as an
answerable inquiry into a particular issue or concern. The research question for the article
was as follows:
Are high doses of fish oil superior to a supplementation of low dose, for knee
osteoarthritis (OA) symptomatic and structural outcomes?
The randomized controlled trial included participants aged more than 40 years, who
were suffering from knee osteoarthritis. The participants were recruited with the help of the

2RESEARCH AND EVIDENCE
ACR diagnostic criteria for OA (Aggarwal et al., 2015). Those meeting the knee pain scores
on the visual analogue scale as >20mm were eligible for the study. Exclusion criteria
included dementia or their the inability of the participants to provide their informed consent,
or those who suffered from severe forms of radiographic knee OA, with respect to index
knee. Furthermore, patients having undergone knee replacement surgeries, and under the
long-term usage of high-dose fish oil were also not recruited.
The randomization procedure involved two groups namely, one that comprised of
administration of high-dose fish oil and another with low-dose fish oil, of 15mL each day.
The high dose fish oil group comprised of 12% DHA and 18% EPA, which in turn provided
an estimated 4.5 g DHA+EPA per day. On the other hand, the other arm was found to be a
blend of oleic rich sunola oil and low-dose fish oil, in the ration of 9:1 that supplied
approximately 0.45g of DHA+EPA per day. This dosage was found to be equal to 1g 1.5
standard fish oil capsules.
Knee specific pain scales that encompassed McMaster and Western Ontario
Universities Arthritis index (WOMAC) was the primary outcome of all patients at time
intervals of 3, 6, 12 and 24 months (Gandek, 2015). WOMAC function, use of analgesic, use
of NSAIDs and the quality of life of the patients were the secondary outcomes. Furthermore,
secondary outcomes were also related to measurement of changes that occurred in the BML
scores and the patient safety outcomes. The patients were also subjected to MRI studies of
their knee at baseline and after 2 years. The quality of life was measured with the use of
Assessment of Quality of Life instrument after every three months. Intake of analgesics and
NSAIDs were measured on a regular basis.
All participants randomised to the two intervention groups were not properly
accounted for at the end of the trial. Although 203 of them had been subjected to the