Digital and analog cables are constructed differently. In analog cable low inductance, low capacitance, low dielectric constant, purity of conductor and good shielding play important role while digital cable should have exact characteristic impedance (usually 110 Ohm for XLR), fast propagation and excellent shielding.
If you use analog XLR cable for digital link you'll get most likely a little fuzzy sound since jitter = noise in time domain (to be exact jitter creates sidebands not harmonically related to root frequency).
Don't save money on this. If you don't need this analog cable then sell it and get good digital cable.