PSMD1 and chronic obstructive pulmonary disease: In the HD group, dialysis time, age, BMI, hypertension, cardiovascular disease, COPD, BUN, and IgG were extracted in a univariate analysis, and patients with shorter dialysis time (less than 4 h) had significantly lower anti-S1 antibody titers in multivariable regression analysis and stepwise regression analysis (Table 4).