Omega-3 fatty acids (n-3, fish oil) have been shown to have anti-inflammatory properties. Therefore, n-3 therapy may be beneficial in chronic inflammatory disorders such as ulcerative colitis.
To systematically review the efficacy and safety of n-3 for maintaining remission in ulcerative colitis (UC).
The following databases were searched from their inception without language restriction: Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Healthstar, PubMed, and ACP journal club. Experts were contacted for unpublished data.
Randomized placebo-controlled trials (RCT) of fish oil for maintenance of remission in UC were included. Studies must have enrolled patients (of any age group) who were in remission at the time of recruitment, and were followed for at least six months. The intervention must have been fish oil given in pre-defined dosage. Co-interventions were allowed only if they were balanced between the study groups. The primary outcome was relapse rate and the secondary outcome was frequency of adverse events. Other outcomes to assess efficacy were change in disease activity scores and time to first relapse.
Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality. Meta-analysis weighted by the Mantel-Haenszel method was performed using RevMan 4.2.8 software. Random or fixed effect models were used according to degree of heterogeneity and subgroup analyses were performed to explore heterogeneity. A sensitivity analysis was performed excluding a study of questionable quality .
The three studies that were included used different formulation and dosing of n-3 but none used enteric coated capsules. The pooled analysis showed a similar relapse rate in the n-3 treated patients and controls (RR 1.02; 95% CI 0.51 to 2.03; P = 0.96). Combining the studies resulted in virtually no statistical heterogeneity (P = 0.93, I(2) = 0%). Various subgroup and sensitivity analyses showed similar results. However, the total number of patients enrolled in these studies was small (n = 138). No significant adverse events were recorded in any of the studies and not enough data were available to pool the other secondary outcomes for meta-analysis.