Omega 3 fatty acids (fish oil) for maintenance of remission in Crohn's disease.Cochrane Database Syst Rev 2007; (2):CD006320CD
The anti-inflammatory effects of n-3 (omega-3 fatty acids, fish oil) have been suggested to be beneficial in chronic inflammatory disorders such as inflammatory bowel disease.
To systematically review the efficacy and safety of n-3 for maintaining remission in Crohn's disease (CD).
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 Experts were contacted for unpublished data.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 n-3 for maintenance of remission in CD 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 or n-3 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 secondary outcomes were change in disease activity scores, time to first relapse and adverse events.
DATA COLLECTION AND ANALYSIS
Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality using Jadad's criteria. Meta-analysis was performed using RevMan 4.2 software, weighted by the Mantel-Haenszel method. Random or fixed effect models were used according to degree of heterogeneity and subgroup analyses were performed to address heterogeneity.
Four studies were eligible for inclusion. There was a non statistically significant benefit of n-3 therapy for maintaining remission (RR 0.64; 95%CI 0.4 to 1.03; P = 0.07). However, the studies were both clinically and statistically heterogeneous (P = 0.01, I(2) = 72%). Three studies used enteric coated capsules (positive effects) and one ordinary gelatin capsules (no advantage). Subgroup analyses of studies which used enteric coated capsules revealed a statistically significant benefit for maintenance of remission (RR 0.49; 95% CI 0.35 to 0.69; RD 0.31; 95% CI 0.19 to 0.43); number needed to treat to prevent relapse in 1 year was 3 (95% CI 2 to 5; I(2) = 19%). However, the total number of patients enrolled in these studies was small (n = 166). No significant adverse events were recorded in any of the studies and not enough data were available to analyze the other secondary outcomes.