Duloxetine Treatment in Patients With OA Knee Pain
Duloxetine Treatment in Patients With OA Knee Pain
This post hoc analysis did not find a differential effect of age on duloxetine treatment in non-depressed patients with OA knee pain. This is an important finding as it suggests that duloxetine is efficacious in the treatment of OA knee pain regardless of age. The lack of an age effect on pain reduction in this patient population is supported by similar findings in a post hoc age-stratified subgroup analysis of duloxetine in the treatment of diabetic peripheral neuropathic pain.
In both older and younger patients, treatment with duloxetine 60 mg/day was associated with significantly greater pain reduction as compared to placebo. However, increasing the dose of duloxetine in older and younger patients, who were not experiencing adequate pain reduction, was not found to provide additional benefit. These findings may be particularly relevant to the treatment of older patients to avoid unnecessary dose escalation.
Overall, duloxetine was generally well tolerated by patients in each age group, considering that rates of completion and discontinuation due to adverse events did not differ significantly or show a tendency toward more drop outs in the older population, and were similar to findings in other studies across indications. Further, adverse events with duloxetine generally did not differ between age groups except that dizziness was associated with greater risk among younger patients relative to older ones. While orthostatic hypotension was the most common treatment-emergent vital sign abnormality reported in each age and treatment group, there was no significant treatment-by-age group interaction.
The interpretation of this post hoc analysis has limitations to be considered. First, neither study was specifically designed to assess safety or efficacy in exclusively older patients. Furthermore, the results of subgroup analyses should generally be interpreted with caution due to concerns about multiple testing and increased likelihood of finding potentially spurious and un-reproducible results.
Discussion
This post hoc analysis did not find a differential effect of age on duloxetine treatment in non-depressed patients with OA knee pain. This is an important finding as it suggests that duloxetine is efficacious in the treatment of OA knee pain regardless of age. The lack of an age effect on pain reduction in this patient population is supported by similar findings in a post hoc age-stratified subgroup analysis of duloxetine in the treatment of diabetic peripheral neuropathic pain.
In both older and younger patients, treatment with duloxetine 60 mg/day was associated with significantly greater pain reduction as compared to placebo. However, increasing the dose of duloxetine in older and younger patients, who were not experiencing adequate pain reduction, was not found to provide additional benefit. These findings may be particularly relevant to the treatment of older patients to avoid unnecessary dose escalation.
Overall, duloxetine was generally well tolerated by patients in each age group, considering that rates of completion and discontinuation due to adverse events did not differ significantly or show a tendency toward more drop outs in the older population, and were similar to findings in other studies across indications. Further, adverse events with duloxetine generally did not differ between age groups except that dizziness was associated with greater risk among younger patients relative to older ones. While orthostatic hypotension was the most common treatment-emergent vital sign abnormality reported in each age and treatment group, there was no significant treatment-by-age group interaction.
The interpretation of this post hoc analysis has limitations to be considered. First, neither study was specifically designed to assess safety or efficacy in exclusively older patients. Furthermore, the results of subgroup analyses should generally be interpreted with caution due to concerns about multiple testing and increased likelihood of finding potentially spurious and un-reproducible results.