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Volume 78 • Number 11
Commentary
Managing Patients With Diabetes: First, Do No Harm
Brian L. Mealey*
O
ne of the great hopes of mankind is the
continuous advancement of scientific knowledge and the implementation of that knowledge to improve quality of life. Medicine and dentistry
continue to make leaps that would have been unimaginable just 20 years ago. As clinicians, we must
persistently evaluate the evidence base and integrate
new information into our practices.
The medical management of diabetes mellitus
has changed markedly in the past decade. Publication of the Diabetes Control and Complications Trial
(DCCT)1 in 1993 and the United Kingdom Prospective Diabetes Study (UKPDS)2 in 1998 forever altered
the world of diabetes care. Prior to the publication
of these landmark studies, people with diabetes did
not know the answer to the basic question, ‘‘If I try
to control my diabetes really well by intensive management regimens, will that make any difference in
my risk for complications of diabetes?’’ Such a basic
question needs an answer because diabetes is a difficult and costly disease to manage. If more intensive
management regimens make no difference in eventual outcomes of the disease, there is little point in
the added cost and effort.
In the DCCT,1 patients were assigned randomly
to one of two groups: 1) intensive insulin therapy in
which subjects took three or more injections of insulin
per day or used a subcutaneous insulin infusion
pump; or 2) conventional therapy using one or two
daily insulin injections. The results of the DCCT provided strong evidence that improved glycemic control
resulting from intensive insulin treatment (hemoglobin A1c [HbA1c] of 7.2% in the intensive treatment
group compared to 8.9% in the conventional treatment group) dramatically decreased the risk for diabetic complications. The prevalence of retinopathy
was reduced by 76% in intensively treated patients
compared to conventional therapy, and the progression of existing retinopathy decreased by 54%. Albuminuria, a sign of nephropathy, was reduced by 54%,
and clinical neuropathy decreased by 60%. Thus, a
change from conventional insulin treatment regimens
to more frequent injection and more intensely monitored therapy resulted in improvement in glycemic
control and dramatic reductions in the risk for diabetes-induced diseases of the eye, kidney, and nerves.
The UKPDS evaluated conventional versus intensive
treatment of patients newly diagnosed with type 2 diabetes. This study also showed a marked reduction in
the complications of diabetes in the intensive treatment group when blood glucose levels were improved
compared to the conventional treatment group.
Since the DCCT and UKPDS were published, physicians have completely changed the way in which
they manage diabetes based on the results of these
studies and the availability of new oral and injectable
agents and insulin analogs that more closely mimic
endogenous insulin secretion.3 Gone are the days of
type 1 patients coming into the dental office taking
one or two injections of intermediate- or long-acting
insulin each day. Instead, they are taking three or four
injections of short-acting insulin each day plus a longacting (basal) insulin, or they are using an insulin
pump. Likewise, it is much more common to see patients with type 2 diabetes come to the dental office
taking multiple oral medications, often in combination with insulin injections, than it is to see type 2 patients taking just one oral medication. These intensive
diabetes management regimens are a boon to people
with diabetes because they reduce the risk for major
complications. There also is evidence that better glycemic control decreases the risk and/or severity of
periodontal diseases and that diabetic patients with
periodontal disease respond more favorably to periodontal treatment when their glycemic control is
good.4 However, the intensive regimens are not without their disadvantages, especially as they relate to
treatment in the dental office.
The most common complication of insulin therapy
is hypoglycemia, a medical emergency with significant potential for negative outcomes. Hypoglycemia
can and does occur in patients using oral agents such
as sulfonylureas; however, its incidence is higher in
those injecting insulin. In the DCCT, the incidence
of severe hypoglycemia was three times greater in
the intensive insulin group compared to those on conventional therapy.5 Severe hypoglycemia was defined
as hypoglycemia in which neurologic impairment was
* Department of Periodontics, University of Texas Health Science Center at
San Antonio, San Antonio, TX.
doi: 10.1902/jop.2007.070362
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Mealey
J Periodontol • November 2007
severe enough that the patient required the assistance
of another person. Remarkably, one-third of all severe
hypoglycemic episodes in the DCCT led to seizures or
coma. Thus, the risk for hypoglycemia should be recognized by dental practitioners as they treat patients
with diabetes, especially those who are taking insulin,
with the caveat that this risk is higher in patients with
type 1 diabetes than in those with type 2 diabetes.
Perhaps even more significant, in the DCCT, 36% of
severe hypoglycemic reactions occurred without
warning symptoms for the patient, and in another
51%, warning symptoms occurred but were not recognized as such by the patients. Therefore, we must be
constantly vigilant in our practices for the signs and
symptoms of hypoglycemia because many patients
will have this complication without any warning given
to us.
Many practitioners I have met and discussed diabetes with seem to have an attitude that says, ‘‘I have
been a dentist for 30 years, and I’ve never had a patient experience a severe hypoglycemic event in my
practice.’’ My answer to that sentiment is two-fold:
1) be thankful that your past experience has been uneventful; and 2) your past experience with this disease
has little relevance to today’s risk. The world of diabetes management is changing every year, and those
changes consistently aim to bring blood glucose
levels closer and closer to the normal range one would
see in people without diabetes. As glycemic control
improves, the risk for hypoglycemia increases. Therefore, we should all expect the incidence of acute complications such as hypoglycemia to increase in our
practices in the future. The old cliché of ‘‘prevention
is the best treatment’’ has never been truer than in
managing today’s diabetic dental patient.
There are two major means by which clinicians can
assess a patient’s risk for hypoglycemia in the dental
office. First, to gain an overall risk assessment, dentists should have documented evidence of the patient’s glycemic control in the recent past. The only
currently available way to garner this information is
to know the patient’s HbA1c values. The HbA1c test
allows determination of blood glucose status during
the 30 to 90 days prior to collection of the blood sample.3,6 As glucose circulates in the bloodstream, it
becomes attached to a portion of the hemoglobin molecule on red blood cells. The higher the plasma glucose levels over time, the greater the percentage of
hemoglobin that becomes glycated, and that percentage is measured using the HbA1c test. The normal
HbA1c value is <6%. The American Diabetes Association (ADA) guidelines3 recommend that people with
diabetes try to maintain glucose levels close to normal
and to keep the HbA1c value <7%. If the HbA1c is >8%,
the ADA recommends physician intervention in the
patient’s management regimen to improve glycemic
Table 1.
Correlation Between HbA1c Levels and
Mean Plasma Glucose Levels
HbA1c (%)
Mean Plasma Glucose (mg/dl)
6
135
7
170
8
205
9
240
10
275
11
310
12
345
control. Table 1 shows how the HbA1c values correlate with average plasma glucose levels.6 As patients’
HbA1c values decrease, their risk for diabetic complications generally decreases as well. However, it is
important to recognize that the risk for in-office hypoglycemia is greater in patients with good glycemic
control than it is in those with poor glycemic control.
The lower the HbA1c, the greater the risk for hypoglycemia. Some patients with poor glycemic control
have wide variability of their glucose levels and can
have swings into the hypoglycemic range, especially
if they take insulin before a dental appointment or do
not eat when they take their usual insulin dose. This
underscores the importance of dentists determining
the true level of glycemic control by obtaining HbA1c
values rather than relying on the patient’s self-report
of their glycemic control. A consult should be sent to
the diabetic patient’s physician to determine the degree of glycemic control. The most objective means
of making this determination is to request the last 2
years of HbA1c values, so one can evaluate not just a
single value but a series of values. The returned consult
from the physician with the HbA1c values from the past
2 years can be placed in the patient’s dental chart for
reference. Questions I ask myself when I receive the
HbA1c values include the following:
Does the patient have consistently elevated HbA1c
values (>8%) and, thus, a lower risk for hypoglycemia
(but a higher risk for long-term diabetic complications)?
Does the patient have HbA1c values consistently
closer to the recommended range (<7%) and, thus,
a higher risk for hypoglycemia in my office?
Does the patient have HbA1c values that fluctuate
widely over time, perhaps indicating patient difficulty
in managing glycemia and a potential for elevated risk
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Managing Dental Patients With Diabetes
Volume 78 • Number 11
for hypoglycemia during periods when glucose levels
are being kept at lower levels?
The second way that clinicians can assess risk for
an acute hypoglycemic event is to determine the
patient’s capillary blood glucose levels prior to beginning dental treatment. Almost all diabetic patients
have glucometers for home use. These devices allow
patients to determine their glucose level in a matter of
seconds from a small drop of blood taken after a finger
stick. My office policy is to have all patients with diabetes bring their glucometers with them to each dental
appointment. This becomes a matter of routine for the
patient, and my experience has been that patients
appreciate my interest in their diabetes management.
Before dental treatment begins, patients check their
blood sugar levels using their own glucometer. I document the glucose in the patient’s chart with an entry,
such as ‘‘Preop glucose = 114 mg/dl by patient glucometer.’’
A normal fasting glucose level is <100 mg/dl. After
a meal, people without diabetes will have a 2-hour
postprandial glucose level <140 mg/dl.3 Symptoms
of hypoglycemia usually are not seen in people without
diabetes until the glucose level decreases to <60 mg/
dl.6 However, symptoms of hypoglycemia may occur
in people with diabetes at glucose levels >60 mg/dl.
After assessing pretreatment glucose levels using
the patient’s glucometer, the clinician must decide
what to do with that information. In general, if the patient is going to undergo a short procedure (<1 hour) in
my office, and the glucose level is ;100 mg/dl, I proceed with treatment. If the procedure is going to last
several hours, and the pretreatment glucometer reading is £100 mg/dl, I give the patient a small amount of
oral carbohydrate before I begin, such as 4 ounces of
fruit juice. This increases glucose levels 30 to 40 mg/
dl in most patients and can help to prevent hypoglycemia from occurring during the procedure. In all
cases, the clinician must remain aware of the potential
for hypoglycemia and be ready to manage that emergency should it arise.
If a clinician wishes to keep a glucometer in the dental office, it is important to know that doing so requires
compliance with the Clinical Laboratory Improvement
Amendments of 1988 and their subsequent amended
provisions. This act is known as CLIA, and it governs
medical laboratories in the United States, including inoffice laboratories. If a dentist elects to keep an office
glucometer, that dentist’s office is considered a medical laboratory under CLIA. The same is true for any
other in-office medical test a dentist may wish to perform, such as an in-office C-reactive protein test or international normalized ratio. Glucometer testing for
the purposes described above is considered a CLIAexempt procedure, meaning that a dental office using
an office glucometer is considered a CLIA-waived medical laboratory. The office still must register with the
government and receive a registration certificate. The
added administrative burden of this process is why most
dental offices prefer to allow patients to test their glucose level using the patient’s own glucometer. More information on CLIA may be found at www.cms.hhs.gov/
clia. The registration form is CMS Form 116.
Another key factor in assessing an individual patient’s risk for hypoglycemia is to have an intimate
knowledge of the diabetes medications each patient
takes. The number of diabetes medications on the
market has exploded in the past decade. Some medications carry very little added risk for hypoglycemia,
whereas others are associated with high risk.
Insulin directly lowers blood glucose levels; therefore, it carries a high risk for hypoglycemia.6 The
Table 2.
Types of Insulin, Listed in Order of Descending Peak Activity Times
Type of Insulin
Insulin Classification
Onset of Activity
Peak Activity
Duration of Activity
Glargine
Long-acting
6 to 8 hours
Peakless (has no peak in activity)
>24 hours
Detemir
Long-acting
1 to 2 hours
Relatively flat (minimal peak)
£24 hours
Ultralente
Long-acting
6 to 10 hours
12 to 16 hours
20 to 30 hours
Lente
Intermediate-acting
3 to 4 hours
4 to 12 hours
16 to 20 hours
NPH
Intermediate-acting
2 to 4 hours
4 to 10 hours
14 to 18 hours
Regular
Short-acting
2 to 3 hours
4 to 12 hours
Lispro
Aspart
Glulisine
Rapid-acting
NPH = neutral protamine Hagedorn.
2074
30 to 60 min
15 min
30 to 90 min
<5 hours
J Periodontol • November 2007
Mealey
various insulins available today Table 3.
have distinct pharmacodynamOral Agents for Diabetes Management
ics, and the dentist must be
aware of the time of peak activity
Risk for
for the insulins a given patient is
Agent
Hypoglycemia
Action
using (Table 2). For example, if
a patient has a 9:00 am dental
Sulfonylureas
Stimulate pancreatic insulin secretion
appointment and she injects a
Glyburide
High
short-acting insulin, such as lisGlipizide
High
pro or aspart, at 8:00 am, peak
Glimepiride
Moderate
insulin activity will take place at
Meglitinides
Stimulate rapid pancreatic insulin secretion
the same time as dental treatRepaglinide
Moderate
ment when blood glucose levels
Nateglinide
Moderate
are becoming lower. This increases the potential for in-office
Biguanides
Block production of glucose by liver, improve
hypoglycemia. With the multiple
Metformin
Low
tissue sensitivity to insulin
injection regimens many diabetic
Thiazolidinediones
Improve tissue sensitivity to insulin
patients use today, it may be difRosiglitazone
Low
ficult to avoid a time of peak
Pioglitazone
Low
activity to provide dental treatment. That is fine, so long as
a-Glucosidase inhibitors
Slow absorption of carbohydrate from gut;
the dental office personnel know
Acarbose
Low
decrease post-prandial peaks in glycemia
how to recognize and treat a
Miglitol
Low
hypoglycemic event. Having paDDP-4 inhibitors (called ‘‘gliptins’’)
Stimulate pancreatic insulin secretion only
tients check their blood glucose
after an increase in glucose level following
Sitagliptin
Low
levels with their glucometers just
a meal; block hepatic glucose production
Vildagliptin
Low
before treatment begins allows
the dentist to get a better idea
Combination agents
Combine actions from two different
of the risk for the glucose level
drug classes; level of risk for hypoglycemia
Metformin + glyburide
High
reaching a critically low point
depends on individual drugs in the
Metformin + glipizide
High
during therapy. A very common
combination agent
Metformin + rosiglitazone
Low
insulin regimen in the United
Metformin + pioglitazone
Low
States today for people with type
Glimepiride + rosiglitazone
Moderate
1 diabetes is an injection of
rapid-acting insulin before each DDP-4 = dipeptidyl peptidase-4.
meal (lispro, aspart, or glulisine)
and an injection of long-acting
the drug is taken alone or in combination with oral
insulin once a day (ultralente, detemir, or glargine).3
agents that do not themselves cause hypoglycemia
Oral agents are used commonly in type 2 diabetes
because the drug stimulates insulin production only
(Table 3). Many of these agents stimulate an increase
when the body needs more insulin after a meal. Exein pancreatic insulin secretion, which increases the
natide can increase the risk for hypoglycemia associrisk for hypoglycemia. Prior to dental treatment, it is
ated with the use of agents that directly stimulate
important for the dentist to make sure that a diabetic
insulin secretion, such as the sulfonylureas and
patient taking one of these agents has eaten. Conmeglitinides. Exenatide also slows gastric emptying,
versely, there are a number of oral medications that
which prevents a sudden increase in blood glucose
pose very little risk for hypoglycemia.
after a meal, and it decreases hepatic glucose proFinally, several newer injected agents have been induction.
troduced since 2005 to improve glycemic control. ExPramlintide is an injected agent taken only by type
enatide is a synthetic version of an incretin hormone
1 and type 2 patients who use insulin. Pramlintide
called exendin-4 and is used by people with type 2 dislows down absorption of carbohydrate from the gut
abetes who also take oral agents. The drug is injected
and decreases hepatic glucose production. Unlike exin the morning before breakfast and in the evening beenatide, pramlintide does not adjust its action to the
fore dinner. Exenatide stimulates insulin secretion,
amount of glucose in the bloodstream. Thus, pramlinbut only in response to increased glucose in the bloodtide has a very high risk for hypoglycemia and, in fact,
stream that follows a meal. This makes it a relatively
carries a ‘‘black box warning’’ from the United States
safe drug with a low incidence of hypoglycemia when
2075
Managing Dental Patients With Diabetes
Food and Drug Administration because of this serious
potential side effect.
It is clear that the medical management of diabetes
has changed. It is equally clear that our management
of these patients in the dental office has not changed
nearly enough. A recent study of general dentists and
periodontists revealed that 77% of periodontists and
44% of generalists always ask patients with diabetes
what type of diabetes they have, and ;80% of periodontists and 56% of generalists ask these patients
about their medical management regimen or about
how well their diabetes is controlled.7 However, only
35% of periodontists and 14% of generalists consistently communicate with the physicians who treat
their dental patients with diabetes, and only 28% of
periodontists and 14% of generalists objectively evaluate glycemic control by consulting the physician
about laboratory values, such as the HbA1c. As diabetes management becomes more complex, as the
number and types of medications increase, and as
physicians continue to stress maintaining glucose
levels at or near the normal range for their patients
with diabetes, it is incumbent upon dentists to recognize the increased risk for medical emergencies in the
office and to be ready to treat those emergencies when
they arise. ‘‘I’ve been a dentist for 30 years and I’ve
never had that happen to me,’’ goes out the window
as soon as the first patient seizes or becomes unconscious in your dental chair.
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Volume 78 • Number 11
REFERENCES
1. Diabetes Control and Complications Trial Research
Group. The effect of intensive treatment of diabetes on
the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J
Med 1993;329:977-986.
2. U.K. Prospective Diabetes Study (UKPDS) Group. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of
complications in patients with type 2 diabetes (UKPDS
33). Lancet 1998;352:837-853.
3. American Diabetes Association. Standards of medical
care in diabetes – 2007 (position statement). Diabetes
Care 2007;30(Suppl. 1):S4-S41.
4. Mealey BL, Oates TW. Diabetes mellitus and
periodontal diseases. J Periodontol 2006;77:12891303.
5. Diabetes Control and Complications Trial Research
Group. Hypoglycemia in the Diabetes Control and
Complications Trial. Diabetes 1997;46:271-286.
6. Mealey BL, Ocampo G. Diabetes mellitus and
periodontal disease. Periodontol 2000 2007;44:127153.
7. Kunzel C, Lalla E, Lamster IB. Management of the
patient who smokes and the diabetic patient in the
dental office. J Periodontol 2006;77:331-340.
Correspondence: Dr. Brian L. Mealey, Department of
Periodontics, University of Texas Health Science Center
at San Antonio, Mail Code 7894, 7703 Floyd Curl Dr., San
Antonio, TX 78248. E-mail: [email protected].
Submitted June 27, 2007; accepted for publication July 3,
2007.