Is paracetamol better than placebo for knee and hip osteoarthritis? A Cochrane review summary with commentary.

Abstract

http://rehabilitation.cochrane.org The aim of this commentary is to discuss in a rehabilitation perspective the published Cochrane Review “Paracetamol vs placebo for knee and hip osteoarthritis1” by Leopoldino et al.,a under the direct supervision of the Cochrane Musculoskeletal Group. This Cochrane Corner is produced in agreement with the International Journal of Rheumatic Disease by Cochrane Rehabilitation. Osteoarthritis is a widespread disease, and one of the most common causes of pain, stiffness, reduced quality of life and, ultimately, disability.2 The cornerstone of any intervention on knee and hip osteoarthritis is pain relief.3 Paracetamol is widely perceived as a safe drug, especially compared to other analgesics such as non-steroidal anti-inflammatory drugs. Currently, many guidelines propose paracetamol as first-line analgesic for hip and knee osteoarthritis.4, 5 However, paracetamol is not free from risks, as it has been linked with increased risk of gastrointestinal, cardiovascular, and kidney diseases, and mortality.6 Moreover, studies have reported that paracetamol has only a small effect on hip and knee osteoarthritis, compared to placebo.7 A Cochrane review addressed this issue investigating current evidence on the efficacy of paracetamol vs placebo in knee and hip osteoarthritis.1 (Leopoldino AO, Machado GC, Ferreira PH, Pinheiro MB, Day R, McLachlan AJ, Hunter DJ, Ferreira ML, 2019) The aim of this Cochrane review was to assess benefits and harms of paracetamol for the treatment of knee and hip osteoarthritis compared with use of placebo. The population addressed in this review included adult patients with osteoarthritis of the hip or knee of any level of health care. The interventions studied were randomized controlled trials comparing benefits and harm of only paracetamol administration vs placebo for the treatment of hip or knee osteoarthritis. The major outcomes were pain intensity, physical function, quality of life, adverse events, withdrawals due to adverse events and liver toxicity. The review authors searched for studies that had been published up to October 2017 in the Cochrane Register of Controlled Trials, MEDLINE, Embase, AMED, CINAHL, Web of Science, LILACS, International Pharmaceutical Abstracts, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform (ICTRP). The review included 10 randomized placebo-controlled trials enrolling a total of 3541 adult patients with knee or hip osteoarthritis. The authors concluded there is high-quality evidence that paracetamol can only minimally affect pain and physical function in people suffering from knee or hip osteoarthritis in the immediate and short term regardless of the dosage, with no risk of adverse events. Moreover, moderate-quality evidence shows that paracetamol increases the number of abnormal liver function tests, but its clinical significance is unclear. Because of the low number of adverse events, the authors were less certain whether paracetamol increases risk of serious adverse events. Paracetamol is widely considered the first choice for treating hip and knee pain due to osteoarthritis. However, this review confirms that the effect of paracetamol for immediate and short-term pain is minimal and probably not clinically relevant. Despite high-quality evidence demonstrating no risk of adverse events, paracetamol should be avoided in monotherapy for hip and knee osteoarthritis and other drugs should be preferred. The authors thank Cochrane Rehabilitation and Cochrane Musculoskeletal Group for reviewing the contents of the Cochrane Corner. The authors declare no conflicts of interest.