medwireNews: Tramadol is associated with improved pain and function among patients with knee and hip osteoarthritis (OA), but this does not necessarily equate to a clinically significant benefit, Chinese study findings indicate.
Moreover, based on the possible gastrointestinal and central nervous system (CNS) adverse events (AEs), “precautions should be taken when prescribing tramadol to OA patients,” say Guanghua Lei (Central South University, Changsha, Hunan, China) and colleagues.
They therefore deduce that “recommending tramadol for a chronic disease like knee or hip OA may not be sufficiently supported by the presented evidence.”
The network meta-analysis included six randomized controlled trials, including a total of 3611 patients with OA affecting the knee or hip who received tramadol 100, 200, or 300 mg/day or placebo. Pain relief and functional improvement were measured at around 12 weeks.
Patients given tramadol 300 mg/day reported significantly greater improvements in pain relief, according to the WOMAC or VAS pain subscales, than those given placebo, with a standardized mean difference (SMD) of 0.30. Meanwhile, patients taking tramadol 200 or 100 mg/day had corresponding SMDs of 0.21 and 0.16 relative to those given placebo.
The researchers also calculated that the highest tramadol dose (300 mg/day) was associated with a 94% likelihood of being the best treatment option of those included in the analysis, using the surface under the cumulative ranking curve statistical approach.
The findings for functional improvement were similar, with tramadol 300 mg/day again associated with the greatest improvement, as measured by the WOMAC function subscale. The SMD between tramadol 300 mg/day and placebo was a significant 0.24 versus a nonsignificant 0.02 and 0.15 for tramadol 200 and 100 mg/day, respectively. And the highest tramadol dose had an 86.2% likelihood of being the best option for improving function.
However, the investigators emphasize that while pain relief and functional improvement were significantly better with tramadol 300 mg/day versus placebo, “the difference was of uncertain clinical importance.”
In addition, all three doses of tramadol were associated with higher rates of AEs compared with placebo, with particularly high rates of gastrointestinal and CNS events. Indeed, patients taking tramadol 300, 200, and 100 mg/day were 6.02-, 4.35-, and 2.29-fold more likely to have a gastrointestinal AE than those given placebo, while the risk for CNS AEs was increased 2.79-, 3.49- and 2.00-fold, respectively.
In the case of gastrointestinal events, the AE risk was dose-dependent, with a 2.64- fold and 1.90-fold increase for patients taking tramadol 300 and 200 mg/day, respectively, relative to 100 mg/day. For CNS AEs, only the 200 mg/day dose showed a significant risk increase over the 100 mg/day dose, at 1.75 fold.
Lei and colleagues add that there were two deaths caused by myocardial infarction and one serious chest pain event among patients given tramadol. Treatment withdrawal due to AEs was more likely with tramadol than placebo, particularly among those taking the highest dose, for whom the risk for withdrawal was a significant 6.78 times higher than for those taking placebo.
Lei and co-authors conclude in Arthritis Care & Research: “This is the first network meta-analysis comparing the efficacy and safety between commonly used doses of tramadol. The findings will help practitioners to optimize the use of tramadol according to its relative risk-benefit profile.”
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Arthritis Care Res 2021; doi:10.1002/acr.24750