Type 2 Diabetes Glycemic
Control From 1988 to 2000, Better But Worse?
Diabetes is controlled in only 36% of the
participants, despite recommendations for
early diagnosis and aggressive treatment in
recent years.
The purpose of the study was to describe
the changes in demographics, antidiabetic
treatment, and glycemic control among
the prevalent U.S. adult diagnosed
type 2 diabetes population between the
National Health and Nutrition
Examination Survey (NHANES) III (1988–1994)
and the initial release of NHANES 1999–2000.
The study population was derived from
NHANES III (n = 1,215) and NHANES 1999–2000
(n = 372) subjects who
reported a diagnosis of type 2 diabetes with
available data on diabetes medication
and HbA1c. Four therapeutic regimens
were defined: diet only, insulin only, oral
antidiabetic drugs (OADs) only, or
OADs plus insulin. Multiple logistic
regression was used to examine
changes in antidiabetic regimens and glycemic
control rates over time, adjusted for
demographic and clinical risk
factors. The outcome measure for glycemic
control was HbA1c. Glycemic
control rates were defined as the proportion
of type 2 diabetic patients with
HbA1c level <7%.
The results showed that dietary treatment
in individuals with diabetes decreased
as the sole therapy from 27.4 to 20.2% between
the surveys. Insulin use also
decreased from 24.2 to 16.4%, while those
on OADs only increased from 45.4 to 52.5%.
Combination of OADs and insulin
increased from 3.1 to 11.0%. Glycemic control
rates declined from 44.5% in NHANES III
(1988–1994) to 35.8% in NHANES
1999–2000.
It was concluded that treatment regimens
among U.S. adults diagnosed with
type 2 diabetes have changed substantially
over the past 10 years. However, a
decrease in glycemic control rates was also
observed during this time period. This trend
may contribute to increased rates
of macrovascular and microvascular diabetic
complications, which may impact health
care costs. Our data support the
public health message of implementation of
early, aggressive management of
diabetes.
Our findings show that the proportion of
adults in the U.S. with adequately
controlled, diagnosed type 2 diabetes
decreased between 1988 and 2000.
Diabetes is controlled in only 36% of the
more recent survey participants, despite
recommendations for early diagnosis
and aggressive treatment in recent years.
We also observed changes in the
demographic distribution of the
adults with diagnosed type 2 diabetes from
NHANES III (1988–1994) to NHANES
1999–2000, such as an increased proportion
of men and minority groups other
than non-Hispanic blacks and Mexican Americans.
In recent years, individuals with diagnosed
diabetes tended to be younger, to
weigh more, and to have a longer duration
of diabetes. However, we found that
these demographic differences did
not fully explain the lower glycemic control
rates seen in recent years. Other
reasons might account for the observed declining
rates over time, such as changes in patient
compliance with treatment programs
despite more aggressive management. Another
possible explanation for this observation may
be surveillance bias due to a
preferential increased screening for diabetes
in high-risk individuals in the late
1990s compared with the previous
decade.
In addition to changes in demographic
features among patients over time,
we also observed changes in the therapeutic
regimen. The proportion of current
individuals with diagnosed diabetes following
diet-only or insulin-only treatment regimens
has decreased since 1988–1994,
but the proportion receiving OADs only or
OADs in combination with insulin has
increased. This change may be due
to a larger selection of marketed oral agents.
The increase in use of OADs from
1994 to 2000 is likely because only
sulfonylureas were available in the earlier
time period. By 2000, at least six
new products in four new classes of OADs had
become available. Another reason for the
observed change may be a trend
toward more aggressive and earlier treatment
with OADs and OAD/insulin combinations.
We have also demonstrated that glycemic
control was better in older
individuals with diagnosed diabetes, those
with higher BMI, and those with a
longer duration of diagnosed diabetes.
Diabetic control was worse in minority ethnic
groups and those taking medications
(as compared with those on diet only).
It is not clear why glycemic control might be
better in older individuals, but
some studies have suggested that older patients
may have better access to medical care, are
more motivated to receive care, and
are more compliant with medication use. This
finding is somewhat in contrast to that of the
U.K. Prospective Diabetes Study (UKPDS),
which suggested that glycemic control
rates among individuals with diabetes decrease
with disease duration and, thus,
with age. Also in contrast to the
current study, Harris et al. found that
obesity was not related to glycemic
control. They attributed their results to
the cross-sectional design of the survey.
We conclude that the proportion of adults
in the U.S. with diagnosed type 2
diabetes that is controlled is inadequate and
less favorable than in previous
years. The cardiovascular and other
consequences of inadequate glycemic
control warrant serious consideration by
treating physicians and others who care for
individuals with diabetes. These
data lend support to public health initiatives
advocating early and aggressive
management of diabetes. Diabetes
Care 27:17-20, 2004
Did
you know: Health
experts have warned of a global epidemic of
diabetes caused by a rise in overweight and
obesity. There are currently 120-140 million
people worldwide with type 2 diabetes, and if
trends continue, this number is predicted to
double in the next 25 years. IDF
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