Background: Gout is triggered by high urate levels and causes inflammation, pain, and an impaired quality of life. Immersion in water at 20-30°C reduces inflammation and pain in arthritis. Yet, relationships of immersion in water at 20-30°C with urate levels and the nucleotide-binding domain (NOD)-like receptor protein 1 (NLRP1) inflammasome have never been clarified.
Objectives: We aimed to investigate the effects of immersion in water at 20-30°C on urate levels, the NLRP1 inflammasome, pain, and quality of life among acute gout patients.
Methods: A community-based randomized control trial design was used with 2 parallel-intervention groups: immersion in water at 20-30°C (20 min/day for 4 weeks) group and a control group. In total, 76 eligible participants in Tomohon City, Indonesia, were assigned using block randomization. We analyze the results (coef. β) and 95% confidence intervals (CIs) using a generalized estimating equation model. We analyzed mediating effects using a path analysis.
Results: Significant pain alleviation (β = -2.06 [95% CI = -2.67∼-1.45]; β = -2.42 [95% CI = -2.97∼-1.87]) and improved quality of life (β = 5.34 [95% CI = 3.12-7.57]; β = 9.93 [95% CI = 7.02-12.83]) were detected at 2 and 4 weeks of follow-up compared to the pre-test and control group. Urate levels (β = -0.34 [95% CI = -0.52∼-0.16]) were reduced at the 2-week follow-up, but there was no significant change in the NLRP1 inflammasome compared to the pre-test and control group after immersion in water at 20-30°C. Both the NLRP1 inflammasome (β = -0.48 [95% CI = -0.63∼-0.34]); water 0.01) and urate levels (β = -0.11 [95% CI = -0.24∼-0.03]; p < 0.01) had partial indirect (mediating) effects on the link between immersion in water at 20-30°C and pain at the 4-week follow-up.
Conclusions: Immersion in water at 20-30°C significantly decreased pain and increased the quality of life. Immersion in water at 20-30°C mediated NLRP1 and urate levels to decrease pain, although it had no significant effect on the NLRP1 inflammasome concentration after 4 weeks of follow-up and reduced urate levels only at 2 weeks after immersion in water at 20-30°C.
Keywords: NLRP1; gout; inflammasome; pain; quality of life; urate; water immersion.