Mean fasting plasma insulin was 6.9 ± 6.7 mcU/mL in SSc, 12.1 ± 7.9 mcU/mL in RA (SSc vs RA p = 0.002) and 9.0 ± 5.9 mcU/mL in non-ARD (SSc vs non-ARD p = 0.083) patients. Here, INS is linked to rheumatoid arthritis.