GPT and rheumatoid arthritis: ALT, alanine aminotransferase; AST, aspartate aminotransferase; CRP, C-reactive protein; DAS28, disease activity score 28; ESR, erythrocyte sedimentation rate; KL, Kellgren–Lawrence; OA, osteoarthritis; RA, rheumatoid arthritis; RF, rheumatoid factor; TLC, total leukocyte count.