When the goal is to achieve a lower
A1C and tighter glycemic control, the
risk of greater frequency and severity of
hypoglycemic episodes also increases. In
the 1,441 patients with type 1 diabetes
studied in the Diabetes Control and
Complications Trial, those who received
intensive diabetes therapy had greater
than three times the risk of having a
severe hypoglycemic episode than
those receiving conventional therapy.29
Although the rates of hypoglycemia
are much lower for patients with type
2 diabetes, there is also increased risk
seen with insulin therapy.30,31 Exogenous
insulin is normally metabolized by the
kidney. However, when there is impairment
of kidney function, the half-life of
insulin is prolonged because of lower
levels of degradation.32 Therefore,
in patients with type 1 diabetes and
moderate to severe kidney dysfunction,
the frequency of hypoglycemic episodes
may be as much as five times that of
patients without kidney disease.33
There are no evidence-based guidelines
or recommendations about which
types of insulin to use or avoid depending
on severity of CKD. Some studies
suggest avoiding long-acting insulin,
whereas others support its use.34 One
small study comparing type 1 diabetic
patients with and without DKD demonstrated
that clearance is reduced for
both regular insulin and insulin lispro;
however, the effect of regular insulin was
also impaired in patients with DKD.35
Thus, a higher dose of regular insulin
may be required, despite lower clearance
in patients with kidney disease. Insulin
lispro did not demonstrate any differences
in metabolic effects on glucose in
patients with or without DKD.35 Regardless
of the form of insulin chosen to