Table 2:
Trials examining the effect of pharmacologic interventions on QoL (grouped by mechanism)
| Author (Year); Country | Patient Sample | Study Design | Intervention | QoL Measure | Findings & Comments* |
|---|---|---|---|---|---|
| Anti-Epileptics | |||||
| Levendoglu et al. (2004); Turkey | SCI patients c/ NP; n=20 (7 female; no race data made available) |
RCT c/ cross-over | Gabapentin, titrated up to 3600 mg/day | Modified Lattinen Test | Significant decrease in intensity and frequency of most descriptors of pain (sharp, hot, unpleasant, deep, and surface) and disability and sleep were significantly better in the GBP treatment group. This was the 1st RCT to include QoL measures, in one of the most commonly used medications for NP treatment, however another measure of QoL would be helpful to capture a fuller picture of effects on health status. |
| Breuer et al. (2007); US | MS patients c/ spinal NP; n=12 (10 female; 8 white, 8 African descent) |
RCT c/ cross-over | Lamotrigine in addition to stable regimen, titrated up to 400 mg | MSQoL-54 | Pilot study showed no significant difference in pain or QoL; did not support need for larger trial. |
| Vranken et al. (2008); Netherlands | Patients c/ NP; subset was spinal; n=40 (19 female; 20 in treatment group; no race data made available); 21 patients with spinal cause |
RCT | Pregabalin in addition to stable regimen, titrated up to 600 mg/day | EQ-5D; SF-36; PDI | There was significant decrease in mean pain score for pregabalin treatment group, compared with placebo. No difference in PDI between groups but treatment group showed significant improvement for the EQ-5D utility score and EQ-5D VAS score compared with the placebo group and SF-36 indicated that treatment led to a significant improvement in the bodily pain domain only. |
| Rossi et al. (2009); Italy | MS patients c/ spinal NP; n=20 (15 female; 12 in treatment group; no race data made available) |
RCT | Levetiracetam, 500 mg/day | MSQoL-54 | Significant reduction in pain for treatment group; no difference in reported QoL, except for the item, ‘overall rating of quality of life.’ |
| Salinas et al. (2012); Colombia | SCI patients s/ NP; n=46 (4 female; 24 in treatment group; no race data made available) |
RCT | Carbamazepine, titrated up to 600 mg/day | SF-36 | This novel study looked at prevention of NP with early treatment, rather than treatment in those who already experience it. Early intervention did not decrease incidence of NP over time and there was no difference in QoL between groups, despite appropriate power. |
| Anti-Depressan ts | |||||
| Vranken et al. (2011); Netherlands | SCI and stroke patients c/ NP; n=48 (24 in treatment group; Table 1, demographics, is missing from manuscript) |
RCT | Duloxetine in addition to stable regimen, titrated up to 60 mg/day | EQ-5D; SF- 36; PDI | No difference in pain intensity with treatment. Treatment group showed a significant improvement for the bodily pain domain only of the SF-36. No significant differences were observed in other QoL indices. The distribution of spinal versus supraspinal NP is said to be in Table 1 (Demographics), but no such table was included in the manuscript and spinal NP could not be separately assessed. |
| Vollmer et al. (2013); US | MS patients c/ spinal NP; n=239 (189 female; 221 white, 15 African descent, 2 Hispanic, 1 Native American; 118 in treatment group); 209 in OLE |
Multi-center RCT, c/ OLE | Duloxetine in addition to stable regimen, titrated up to 60 mg/day in RCT and up to 120 mg/day in OLE | MSQoL-54 | This well-conceived, well-executed, international study showed significant pain reduction in treatment group; QoL was not impacted. In OLE, pain reduction was reported in patients in both groups, with greater improvement reported by patients who had received placebo during the acute phase. |
| Cannabinoids | |||||
| Svendsen et al. (2004); Denmark | MS patients c/ spinal NP; n=24 (14 female; no race data made available) |
RCT c/ crossover | Dronabinol, titrated up to 10 mg | SF-36 | Pain intensity and reduction significantly improved on treatment; the only improvements to QoL were seen in bodily pain and mental health. |
| Turcotte et al. (2015); Canada | MS patients c/ NP refractory to GPB; n=15 (13 female; 8 in treatment group; no race data made available) | RCT | Nabilone, titrated up to 1 mg, in addition to stable GBP dose | VASimpact | This small but well-designed study explores the important need for combining medication therapies, and shows that combination of GBP with nabilone significantly reduces pain. No change in pain impact was noted, however, the use of a VAS to capture impact of pain may have been inadequate and a more comprehensive measure of QoL would have been prudent. |
| Opioids | |||||
| Norrbrink & Lundeberg (2009); Sweden | SCI patients c/ NP; n=35 (7 female; 23 in treatment group; no race data made available) |
Multi-center RCT | Tramadol in addition to stable regimen, titrated up to 400 mg/day | LiSat-9 | Decrease in pain intensity in treatment group compared with those on placebo. Global life satisfaction improved in placebo group only. |
| Barrera-Chacon et al. (2011); Spain | SCI patients c/ NP refractory to AED treatment; n=54 (10 female; no race data made available) |
Multi-center, observational descriptive | Oxycodone, usually in conjunction with AED use | Modified EQ-5D | Significant decrease in pain intensity, improved health-related QoL and diminished impact of pain on physical activity and sleep. As doses of oxycodone were not investigated, further research in controlled trials assessing appropriate dosing for NP treatment is warranted. |
| Other | |||||
| Han et al. (2016); Korea | SCI patients c/ NP; n=40 (14 female; 20 in treatment group; no race data made available) | Multi-center RCT | BTX-A, 200 U subcutaneous injection, in addition to stable regimen | WHOQOL-BREF | The BTX-A group showed significant reductions in pain score at 4 and 8 weeks following injection, compared to placebo. Trend towards significant impact in physical health domain of QoL only. |
| Gonzalez et al. (2006); Sweden | Post-polio syndrome patients; subset had NP; n=142; 75 patients with NP (33 of whom are in treatment group; 92 females in total group, not differentiated by pain status; no race data made available) |
RCT | IVIG, 90 g over 3 days c/ 2nd equal dose at 3 months | SF-36 | Pain assessment was a secondary end-point of this study that primarily assessed strength, and not all patients included had NP. In the subcohort of patients with significant pain, those receiving IVIG had a greater pain reduction. QoL did not differ between groups. |
*
values were considered significant at p<0.05, unless otherwise noted
SCI=spinal cord injury; MS=multiple sclerosis; NP=neuropathic pain; RCT=Randomized Controlled Trial; GBP=gabapentin; MSQoL=Multiple Sclerosis Quality of Life instrument; EQ-5D=EuroQoL-5 Dimensions instrument; VAS=Visual Analog Scale; WHOQOL-BREF=World Health Organization Quality of Life-abbreviated; PDI=Pain Disability Index; SF-36=Short Form 36 health survey; OLE=open-label extension; BTX-A= botulinum toxin type A; IVIG= Intravenous immunoglobulin