CRP and rheumatoid arthritis: The results of analysis showed positive RF (OR = 1.72, 95% CI: 1.47–2.01; P < 0.00001) (Fig 7), positive ACPA (OR = 1.58, 95% CI: 1.31–1.90; P < 0.00001) (Fig 8), RF titer (WMD = 183.62 (IU/mL), 95% CI: 66.94–300.30; P = 0.002) (Fig 9), ACPA titer (WMD = 194.18 (IU/mL), 95% CI: 115.89–272.47; P < 0.00001) (Fig 10), ESR level (WMD = 7.41 (mm/h), 95% CI: 2.21–12.61; P = 0.005) (Fig 11), and CRP level (WMD = 4.98 (mg/L), 95% CI: 0.76–9.20; P = 0.02) (Fig 12) were associated with increased risk of RA-ILD.