If left untreated or improperly controlled, type 2 diabetes can lead to life-threatening complications such as neuropathy, heart attack, high blood pressure, stroke or glaucoma, states the Mayo Clinic. Nerve damage is common in patients with high blood sugar levels and can cause numbness in the limbs.
Kidney damage is another complication of diabetes, according to the Mayo Clinic. Additionally, diabetes patients may suffer from diabetic retinopathy, a condition that causes damage to the eye vessels that may lead to permanent blindness. Diabetics are more likely to suffer from bacterial and fungal skin infections, hearing impairment and foot damage due to poor blood circulation.