Diet

Author Year

Country
PEDro Score
Research Design
Total Sample Size

Methods Outcome
Allison et al. 2016

Canada

RCT

PEDro=8

N=20

Population: 48.7±14.0 yr; Gender: males=10, females=10; Time since injury=13.1±10.8 yr; Level of injury: C=12, T=6, L=2; Severity of injury: AIS A=7, B=2, C=3, D=8; Type of pain=neuropathic.

Intervention: Participants were randomized to either a control group or an anti-inflammatory diet group for 12 wks.

Outcome Measures: Center for epidemiological studies depression scale (CES-D), self-report neuropathic pain questionnaire (NPQ), change in inflammatory mediators (IL-2, IL-6, IL-1β, TNF-α and IFN-y) and relationship between pain and inflammatory mediators.

1.     Significant group X time interaction for CES-D score (p=0.01) and significant reduction in CES-D score from baseline to 3 mo (p<0.01).

2.     Significant group X time interaction for sensory component of self-report neuropathic pain scores (p<0.01).

3.     Significant reduction in pain sensory scores from baseline to 3 mo in the treatment group (p<0.01).

4.     Significant increase in pain sensory scores from baseline to 1 mo in control group (p=0.04) but not from baseline to 3 mo (p=0.21).

5.     No significant group X interaction for the affective component of the self-report neuropathic pain scores (p=0.17).

6.     Change scores of sensitivity pain found not to be significantly different between treatment and control groups (p=0.35) and no significant changes within the group for sensitivity pain scores (treatment: p=0.19; control: p=0.96).

7.     Proinflammatory composite score (average of IL-2, IL-6, IL-1β, TNF-α and IFN-y) was significantly different between the control and treatment groups (p=0.01) and there was a significant reduction found in the treatment group from baseline to 3 mo (p=0.02) but no significant change in the control group (p=0.07).

8.     Mann-Whitney test indicated significantly different change scores between the treatment group and the control group for IFN-y (p=0.01), IL-1β (p=0.01), and IL-2 (p=0.01) and a trend for CRP (p = 0.10).

9.     Friedman test showed a statistically significant reduction in IFN-y (p=0.01), IL-1β (p<0.01), IL-6 (p<0.05), and a trend for CRP (p=0.10) in the treatment group and no significant changes in the control group (p>0.05).

10.   Wilcoxon signed-rank test indicated a significant reduction in IFN-y (p=0.01) and IL-1β (p<0.01) as well as a trend for IL-6 (p=0.08) in the treatment group with no significant changes in control group (p>0.05).

11.   Significant positive correlation between reduced pain score and PGE2 (p=0.01).

12.   Significant positive correlation between change in sensitivity score and proinflammatory cytokines IL-1β and IL-2 and eicosanoid PGE2 (p=0.008).

Allison and Ditor, 2018

Canada

Secondary Analysis of RCT (Allison et al. 2016)

N=5

Population: Mean age=51.5±15.3 yr; Gender: males=1, females=4; Time since injury=12.8±11.3 yr; Level of injury: C=2, T=3, L=0; Severity of injury: AIS A=2, B/C=0, D=3; Type of pain=neuropathic.

Intervention: Original study – Participants were randomized to either a control group or an anti-inflammatory diet group for 12 wks.

This study – Taking a look at 5 of the original participants 1 yr later and making assessments.

Outcome Measures: Dietary compliance and center for epidemiological studies depression scale (CES-D), neuropathic pain questionnaire (NPQ).

1.     Dietary compliance significantly varied between end of the study and the 1 yr follow-up (p<0.01) and a significant reduction in compliance scores from 3 mo to 1 yr (p<0.01) as they were no longer significantly different from baseline (p=0.18).

2.     CES-D showed a trend toward an increase from 3 mo to 1 yr follow-up (p=0.10) as they were no longer significantly different from baseline (p=0.74).

3.     No significant difference in NPQ sensory scores from 3 mo to follow-up (p=0.42), and scores remained significantly different from baseline (p=0.02).

4.     Significant increase in NPQ affective scores from 3 mo to follow-up (p=0.05) as they were not longer significantly different from baseline (p=0.24).

5.     No significant difference in NPQ sensitivity scores from 3 mo to follow-up (p=0.34) but follow-up scores were also not significantly different from baseline (p=0.15).

Discussion

One small RCT (Allison et al. 2016) found randomized participants to either a control group or to an anti-inflammatory diet group for 12 weeks. They found that significant reductions occurred for the anti-inflammatory group in pain sensory scores and in pro-inflammatory composite scores, though the differences were not significant between groups on change scores of pain sensitivity or in the affective component of reported neuropathic pain levels.

Conclusion

There is level 1b evidence that inflammatory diet results in significant reduction in neuropathic pain post SCI.

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