Safety of Intra-articular Hyaluronic Acid Injections in Osteoarthritis: Outcomes of a Systematic Review and Meta-Analysis.

BACKGROUND: Some controversy exists regarding the safety of intra-articular hyaluronic acid (IAHA) in the management of osteoarthritis (OA). OBJECTIVE: The objective of this study was to re-assess the safety profile of IAHA in patients with OA, through a comprehensive meta-analysis of randomized, placebo-controlled trials. METHODS: A comprehensive literature search was undertaken in the databases MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), and Scopus. Randomized, double-blind, placebo-controlled, parallel-group trials that assessed adverse events (AEs) with IAHA in patients with OA were eligible for inclusion. Authors and/or study sponsors were contacted to obtain the full report of AEs. The primary outcomes were overall severe and serious AEs, as well as the following MedDRA System Organ Class (SOC)-related AEs: gastrointestinal, cardiac, vascular, respiratory, nervous system, skin and subcutaneous tissue disorders, musculoskeletal, renal and urinary disorders, infections and infestations, and hypersensitivity reaction. RESULTS: Database searches initially identified 1481 records. After exclusions according to the selection criteria, 22 studies were included in the qualitative synthesis, and nine studies having adequate data were ultimately included in the meta-analysis. From the studies excluded according to the pre-specified selection criteria, 21 with other pharmacological OA treatments permitted during the trials were a posteriori included in a parallel qualitative synthesis, from which eight studies with adequate data were finally included in a parallel meta-analysis. Since this meta-analysis was designed to assess safety, the exclusion criterion on concomitant anti-OA medication was crucial. However, due to the high number of studies that allowed mainly concomitant oral non-steroidal anti-inflammatory drugs (NSAIDs), we decided to include them in a post hoc parallel analysis in order to compare the results from the two analyses. No statistically significant difference in odds was found between IAHA and placebo for all types of SOC-related disorders, except for infections and infestations, for which significantly lower odds were found with IAHA compared with placebo, both overall (odds ratio [OR] = 0.61, 95% confidence interval [CI] 0.40-0.93; I2 = 0%) and in studies without concomitant anti-OA medication (OR = 0.49, 95% CI 0.27-0.89). There were significant increased odds of reporting serious AEs with IAHA compared with placebo, both overall (OR = 1.78, 95% CI 1.21-2.63; I2 = 0%) and in studies with concomitant anti-OA medication (OR = 1.78, 95% CI 1.10-2.89), but not in studies without concomitant anti-OA medication (OR = 1.78, 95% CI 0.92-3.47). CONCLUSIONS: Using the available data on studies without any concomitant anti-OA medication permitted during clinical trials, IAHA seems not to be associated with any safety issue in the management of OA. However, this evidence was associated with only a "low" to "moderate" certainty. A possible association with increased risk of serious AEs, particularly when used with concomitant OA medications, requires further investigation.