Inulin supplementation and physiotherapy-supported exercise each reduced pain in patients with knee osteoarthritis over a period of 6 weeks, with no synergistic effect observed when combined.
In a 2 × 2 factorial randomized controlled trial, researchers evaluated the outcomes of 117 community-dwelling patients with knee osteoarthritis assigned to receive inulin, undergo physiotherapy-supported exercise, partake in both interventions, or take placebo. The primary outcome was change in pain measured by the Numerical Rating Scale.
Compared with placebo, pain improved with inulin (baseline-adjusted mean difference = −1.11 points) and physiotherapy-supported exercise (baseline-adjusted mean difference = −1.55 points). The combined intervention also reduced pain (baseline-adjusted mean difference = −1.67 points), but no synergistic effect was observed, and the study wasn't powered to detect interaction. Both interventions exceeded the minimum clinically important difference of 1 point for Numerical Rating Scale improvement.
Physiotherapy-supported exercise improved 30-second sit-to-stand performance by 2.76 repetitions and timed up-and-go performance by −0.66 seconds compared with placebo. Inulin improved grip strength by 4.62 units, whereas no statistically significant improvements were observed with physiotherapy-supported exercise or the combined intervention.
Further, inulin was associated with higher pressure pain thresholds and reduced temporal summation, consistent with improvements in proximal and central sensitization. No such effects were observed with physiotherapy-supported exercise.
Biomarker analyses showed that inulin increased circulating butyrate and glucagon-like peptide (GLP)-1, but no statistically significant correlations were identified between short-chain fatty acids and clinical outcomes. Higher GLP-1 levels were associated with improved grip strength in exploratory analyses.
Dropout rates were lower in the inulin group compared with the physiotherapy-supported exercise group (3.6% vs 21%). Minor gastrointestinal adverse events were reported with inulin but didn't lead to noncompliance or withdrawal.
The researchers used analysis of covariance adjusted for baseline values and included a sensitivity intention-to-treat analysis with multiple imputation for missing data, with results consistent in direction and magnitude. Allocation probabilities were modified during recruitment to preferentially recruit participants into the physiotherapy-supported exercise arms, and dropout rates were higher in those arms.
The participants couldn't be blinded to physiotherapy-supported exercise allocation. Modification of allocation probabilities introduced potential temporal confounding, and the intervention duration was 6 weeks. GLP-1 findings were exploratory, not prespecified, and required independent replication.
“These results provide a novel perspective on [osteoarthritis] management, highlighting the potential for integrating dietary interventions alongside pharmacologic treatments and promoting a more holistic approach to patient care,” wrote lead study author Afroditi Kouraki, of the University of Nottingham School of Medicine, and colleagues.
Senior study author Ana M. Valdes and co–study author Amrita Vijay reported being members of the Chuckling Goat Scientific Advisory Board and Ana M. Valdes also reported being a member of the OLIPOP Scientific Advisory Board. However, these are not related to the study. The study authors reported no other conflicts of interest.
Source: Nutrients
