Apart from blood sugar control what’s new in the prevention of the microvascular complications of diabetes?
Retinopathy
At diagnosis, 10.5% of type two diabetics already have retinopathy. New research has shown that severe proliferative diabetic neuropathy can be predicted by measuring the size of retinal blood vessels, but this is still being developed in research centres. It could become a part of the usual screening process in the future.
Lowering blood pressure in those who are hypertensive by at least 10 points, can reduce the onset of retinopathy but does not affect the rate at which it develops into proliferative retinopathy. What does seem to work is the use of oral Fenofibrate.
Laser photocoagulation reduces the rate of progression of proliferative retinopathy and the onset of severe visual loss. Direct injection of drugs that inhibit Vascular Endothelial Growth Factor such as pegaptanib, ranibizumab, and bevacizumab also help but they are less freely available, due to cost.
Nephropathy
NICE recommend spot urinary albumin to the creatinine ratio and glomerular filtration rate on diagnosis and then yearly. If the rate is raised on 2 out of 3 samples within six months then nephropathy is confirmed and the severity graded.
Blood pressure targets are 140/90 for those without nephropathy and 130/80 for those that have it. Some people may benefit from lower blood pressure targets of 120 systolic such as Asian, Hispanic and African American populations.
Both ACE inhibitors and Sartans (ARB) reduce nephropathy and ACE inhibitors also improve all- cause mortality. These drugs are the first choice for most diabetics when prescribing anti-hypertensives.
Early referral to a nephrologist showed an improvement in interventions and mortality rates. There was also a small improvement in kidney function when the new drug Dapagliflozin was used.
Neuropathy
There are other causes of neuropathy that may need to be considered before diabetic neuropathy is diagnosed. These are: alcohol, chemotherapy, vitamin B12 deficiency, hypothyroidism, renal disease, paraneoplastic syndromes due to eg multiple myeloma and bronchogenic carcinoma, HIV infection, chronic inflammatory demyelinating neuropathy, inherited neuropathies and vasculitis.
A new Japanese drug Epalrestat improved diabetic neuropathy but did not improve autonomic neuropathy.
There was insufficient evidence to show that exercise, pulse infrared light therapy, education about foot ulceration and complex interventions such as combining patient education, podiatry care, foot ulceration assessment, motivational coaching to provide self- care, worked or not.
BMJ 4th February 2017 Willy Marcos Valencia and Hermez Florez from Miami Florida.
BMJ 2017;356:i6505
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