After PSM, independent risk factors for all-cause mortality were gangrene (HR = 3.003, 95% CI = 1.343–9.431), cardiac involved (HR = 5.370, 95% CI = 1.910–15.472), Scl-70 (HR = 3.569, 95% CI = 1.333–10.869), elevated BNP (HR = 2.135, 95% CI = 1.293–9.564) (Table 4). Here, NPPB is linked to gangrene.