Systematic review and meta-analysis: Is there any role for antioxidant therapy for pain in chronic pancreatitis.

Chronic pancreatitis (CP) is an irreversible disease with increased oxidative stress. The therapeutic role of antioxidants for pain reduction in CP is debatable. A systematic review of articles in PubMed and Embase until February 2020 was performed. Only randomized controlled trials conducted on humans to evaluate the therapeutic effects of antioxidants for pain in CP were included. Studies of other design, nonhuman studies, and those that did not objectively assess pain were excluded. Twelve articles and four articles were eligible for qualitative and quantitative analysis, respectively. The four included studies had a total of 352 participants. Pain reduction as measured by a visual analog scale was not significantly different in the antioxidant group compared to placebo (standardized mean difference = -0.14 [95% confidence interval [CI] = -0.44 to 0.17]; = 0.38). Number of pain-free participants was also similar (odds ratio [OR] = 1.59 [0.97-2.59]; = 0.06). There was no difference in outcome when comparing different etiologies of CP or age group. The reduction in the number of analgesics used did not differ between both groups. Antioxidants were not associated with increased adverse events (OR = 2.59 [CI = 0.77-8.69]; = 0.12). A qualitative analysis on the effect on quality of life did not suggest any significant improvement with antioxidants. There was no significant pain reduction or change in quality of life in CP patients with use of antioxidants. This makes their routine use in the management of CP questionable. However, further studies may identify a subgroup where they are more useful.