Help! could stage 3 kidney disease cause constipation?

Yes: The diet/medications that we use for people with stage 3 CKD can cause constipation. Use of metamucil or its generic equivalent is generally all that's needed to overcome this. However, this can worsen as the kidney disease progresses. Since the colon is responsible for up to 60% of potassium excretion in patients with advanced kidney disease, you need to work closely with your doc to avoid this.