Should You Be Taking Insulin for Type 2
New research suggests that starting insulin
therapy earlier may be beneficial.
The first treatment for people newly diagnosed with type 2 diabetes
is usually lifestyle changes, such as improvements in diet and
exercise. If these measures do not sufficiently control blood
glucose levels, one or more oral medications (often metformin
and/or a sulfonylurea drug) are prescribed. Over time, type 2
diabetes usually worsens, oral medications become less effective,
and more than a third of people must add insulin injections to
their treatment regimen.
New research, however, is challenging this treatment approach,
suggesting that adding insulin earlier can greatly improve blood
glucose control. In addition, newer insulin formulations such
as insulin glargine are convenient to take and less likely than
older types to cause hypoglycemia—a big concern for many
people who are beginning insulin therapy.
Why Some People With Type 2 Diabetes Need Insulin
Unlike people with type 1 diabetes, who are unable to produce
their own insulin and require insulin injections to survive,
people with type 2 diabetes do produce insulin. The problem in
type 2 diabetes is that the cells are less responsive to the
actions of insulin. The pancreas compensates by producing more
insulin, but over time it cannot produce enough to overcome the
cells’ reduced response. In addition, as type 2 diabetes
progresses, the ability of the pancreas to produce insulin may
become impaired, and the body does not have enough insulin to
move glucose into cells.
Evidence for Change
A 2004 review article in The American Journal of Medicine points
out that many people with type 2 diabetes are not prescribed
insulin until 10 to 15 years after their diagnosis and often
not until complications from the disease have already occurred.
The author calls this practice outdated and ineffectual and points
to an emerging trend that involves the earlier use of insulin
to help people with type 2 diabetes control their blood glucose
levels and reduce their risk of complications.
The article points out that for many people, lifestyle changes
and oral medication are not enough. For example, a substudy of
the UKPDS (see page 26 for more information) found that six years
after diagnosis, more than 50% of people with type 2 diabetes
treated with a sulfonylurea alone needed insulin injections to
achieve their target blood glucose levels. In addition, 50% of
those who took insulin plus a sulfonylurea had a desirable median
HbA1c level of 6.7% after six years.
Newer Types of Insulin
Earlier addition of insulin is made even more attractive by
newer types of insulin that reduce the risk of side effects.
The review author points to two recent clinical trials supporting
this idea. (The first, published in the Annals of Internal
Medicine in 2003, compared three treatment regimens: the
oral medication glimepiride (Amaryl) with NPH insulin at bedtime;
glimepiride with insulin glargine at bedtime; and glimepiride
with morning insulin glargine. After 24 weeks, fewer patients
taking insulin glargine (17% for bedtime and 23% for morning)
experienced hypoglycemia during the night than those taking NPH
insulin (38%). HbA1c levels also decreased more significantly
with insulin glargine: -1.24% for morning insulin glargine, -0.96%
for bedtime insulin glargine, and -0.84% for NPH insulin.
The other study, published in Diabetes Care in 2003,
compared insulin glargine and NPH insulin when added to a treatment
plan that already included oral therapy. After 24 weeks, 58%
of participants randomized to bedtime insulin glargine achieved
an HbA1c level of less than or equal to 7%, similar to the 57%
of those taking bedtime NPH insulin. However, more participants
(33%) taking insulin glargine achieved that goal without a single
incident of hypoglycemia than did participants taking NPH insulin
The Bottom Line
The author of the 2004 review article, as well as another author
in the same issue of The American Journal of Medicine, suggests
that in treating people with type 2 diabetes, the ideal may be
aggressive treatment to keep patients at an HbA1c level of less
than 7% for life. In practical terms, for a newly diagnosed person
with type 2 diabetes, the treatment plan might still follow the
same pattern: lifestyle changes, followed by oral medications,
followed by the addition of insulin. However, each step might
be given only a few months to work; if the target HbA1c level
is not reached, treatment would progress to the next step.
Many people are reluctant to begin insulin therapy, feeling
that the change means they have failed or their diabetes will
worsen. These and other obstacles—such as the fear of hypoglycemia,
weight gain, or pain caused by the needles—are surmountable,
suggests the author of the first review article mentioned above.
He adds, “Most importantly,…the concept of insulin
as expected therapy in the management of type 2 diabetes should
be introduced on diagnosis, whether or not the patient’s
blood glucose levels at the time can be adequately controlled
by other means. Better adherence and more successful outcomes
will result when the erroneous idea that insulin therapy is a
sign of failure or worsening disease is permanently dispelled.”