There are real risks in the actual donation, of course. And some lifelong things you need to worry about. It does affect treatment of other things. For example, if you happen to have a rotator cuff injury, you can't just take high doses of anti-inflammatory meds for a month. You have to do physical therapy and steroid injections. And, in our wonderful US healthcare system, you'll get near-zero aftercare beyond a few months worth of checkups. You'll have to advocate for yourself for later extra checks on your remaining kidney's health and often have to foot the bill yourself because your overpriced insurance will refuse to pay for it.

Source: Am a kidney donor living in the US that has experienced both of the above and several similar issues