Table 4 Analysis of the mediating effect of frailty and depression on social support and self-management in elderly patients with COPD (N = 627)

Indirect effect 1

social support → frailty → SM

-0.010

-0.061

0.036

-

Indirect effect 2

social support → depression → SM

0.290

0.161

0.436

14.45%

Indirect effect 3

social support → frailty → depression → SM

0.040

0.010

0.081

1.99%

Total indirect effect

0.320

0.182

0.476

15.94%

Direct effect

social support → SM

1.687

1.359

2.015

84.06%

Total effect

2.007

1.695

2.318