Efficacy of Extracts of Oleogum Resin of Boswellia in the Treatment of Knee Osteoarthritis: A Systematic Review and Meta‐Analysis

Background: Knee osteoarthritis (OA) has recently been ranked as the 11th highest contributor to global disability. More than 40% of the patients use complementary and alternative medicine including supplements containing phytoextracts with anti-inflammatory properties as those from Boswellia genus. Objective: The aim of this meta-analysis was to evaluate the efficacy of phytoextracts from the oleogum resin of the Boswellia genus as a supplementation for patients affected by knee OA. Search Methods: Four electronic databases were used for the research and PRISMA statements were followed throughout the study. Selection Criteria: The following inclusion criteria were used: a) the subjects of the study were humans with a diagnosis of knee OA reported by medical staff; b) randomisation and the presence of a control (placebo, negative or positive control), and c) outcomes reported with WOMAC and/or VAS score. Data collection and analysis: Publication bias was assessed with funnel plot and through the Egger test. Jadad scale was used in order to assess the quality of the studies included. The statistical heterogeneity was assessed using I2 statistics. Results of meta-analysis and sub-group analysis were reported using forest plot. Results: A total of 13 studies involving 850 (WOMAC) and 1185 (VAS) patients met the inclusion criteria. The meta-analysis did not detect a significant effect of the use of Boswellia extracts between the control and the treatment groups due to the high heterogeneity of the studies (p=0.0865 for WOMAC) and (p= 0.3966 VAS). However, the subsequent sub-group analysis demonstrated the significant beneficial effect of Boswellia extracts with respect to a placebo (lower WOMAC score in the treatment groups). This was also confirmed in the meta-regression applied to the WOMAC scores. Conclusion: Boswellia extracts showed potential benefits in the treatment of knee OA respect to a placebo using the WOMAC score. This is an important finding as people exposed to NSAID-related adverse effects could benefit from the use of Boswellia extracts. However, further high-quality studies are needed to establish the clinical efficacy of extracts from genus Boswellia.