borderline significantp -value = 0.053
Nevertheless, a borderline significant difference ( p -value = 0.053 for testing interaction) was observed in the association between metformin use and total joint replacement for patients with concurrent use of pain drugs (HR = 1.24, 95% CI = 0.63–2.45) vs. without (HR = 0.56, 95% CI = 0.36–0.89) (Supplementary Table S2 ).