Sikutaka kukushtua but now that you ask, main complications of diabetes:

1. Microangiopathy. This simply means damage to the small body vessels in the body. This eventually results in elevated blood pressure and it's quite common to see diabetic patients who also have concurrent hypertension.

2. Retinopathy. Due to damage to the small vessels, the retina is not adequately perfused. As a result, over time it is adversely affected and patients begin to experience progressively worsening vision culminating in blindness. Cataracts are also common in diabetes.

3. Erectile dysfunction. This results mainly because of damage to the small vessels that perfuse the vital gear, which has a direct, negative effect on both the organ's muscles as well as its nerves. Failure to rise to the occasion/bendera nusu mlingoti is a reality.

4. Neuropathy. Again due to damage of those small blood vessels, the nerves are adversely affected. As a result, it's common to hear of some diabetic patients complaining of a tingling sensation in the legs. At its worst, patients are unable to walk. For this reason, it's quite possible for a diabetic patient to hurt their feet/legs and feel no pain at all since the nerves are not functioning as they should. As part of management, patients are taught diabetic foot care which among other things includes observing the soles of your feet using a mirror.

It's worth noting here that some of the medicines commonly used to manage diabetes can also cause this as a side effect e.g Metformin if used at consistently higher doses (>2.4gm daily) over a long period of time.


5. Nephropathy. Basically, kidney disease. Small blood vessels once again. Once damaged, kidneys in adequately perfused resulting in renal failure. This portends a myriad of challenges because of the critical role the kidney plays in:
>maintenance of blood pressure by regulating blood volume. Renal failure easily results in hypertension.
>vitamin D activation. One of the roles of the kidney is in activation of vitamin D in the body and if kidneys fail, you can begin to see your bones giving way shortly.
>red blood cell synthesis. Your kidneys are responsible for releasing the hormone erythropoietin (in response to other stimuli of course) which signals your bone marrow to manufacture red blood cells. Once again if they fail, anemia lurks around the corner.

Please note, too, that hypertension itself also damages your kidneys.

6. Diminished immunity. Diabetes, if undiagnosed or poorly managed, lowers your body's immunity thus making you susceptible to infections such as skin infections, upper respiratory tract infections (URTIs) as well as vaginal candidiasis for the sockets (for the record, I didn't say candidiasis is a tell-tale sign of diabetes, no!). It's also for this reason that many diabetics have a problem in healing wounds often culminating in amputations.

There obviously are many others which are by no means any less important e.g hearing loss, HONK (Hyper-Osmotic Non-Ketotic) coma, DKA (diabetic KetoAcidosis, always a medical emergency), stroke, stress, etc. also note that most of these are gradual and insidious in their onset, often taking many years to fully manifest.

See more here.