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BMC Health Services Research
Open Access
Research article
An examination of periodontal treatment and per member per
month (PMPM) medical costs in an insured population
David A Albert*
1
, Donald Sadowsky
1
, Panos Papapanou
1
, Mary L Conicella
2
and Angela Ward
1
Address:
1
Columbia University College of Dental Medicine, New York, New York, USA and
2
Aetna, Fairfield, New Jersey, USA
Email: David A Albert* - daa1@columbia.edu; Donald Sadowsky - ds8@columbia.edu; Panos Papapanou - pp192@columbia.edu;
Mary L Conicella - ConnicellaML@aetna.com; Angela Ward - aw527@columbia.edu
* Corresponding author
Abstract
Background: Chronic medical conditions have been associated with periodontal disease. This study
examined if periodontal treatment can contribute to changes in overall risk and medical expenditures for
three chronic conditions [Diabetes Mellitus (DM), Coronary Artery Disease (CAD), and Cerebrovascular
Disease (CVD)].
Methods: 116,306 enrollees participating in a preferred provider organization (PPO) insurance plan with
continuous dental and medical coverage between January 1, 2001 and December 30, 2002, exhibiting one
of three chronic conditions (DM, CAD, or CVD) were examined. This study was a population-based
retrospective cohort study. Aggregate costs for medical services were used as a proxy for overall disease
burden. The cost for medical care was measured in Per Member Per Month (PMPM) dollars by aggregating
all medical expenditures by diagnoses that corresponded to the International Classification of Diseases, 9
th
Edition, (ICD-9) codebook. To control for differences in the overall disease burden of each group, a
previously calculated retrospective risk score utilizing Symmetry Health Data Systems, Inc. Episode Risk
Groups™ (ERGs) were utilized for DM, CAD or CVD diagnosis groups within distinct dental services
groups including; periodontal treatment (periodontitis or gingivitis), dental maintenance services (DMS),
other dental services, or to a no dental services group. The differences between group means were tested
for statistical significance using log-transformed values of the individual total paid amounts.
Results: The DM, CAD and CVD condition groups who received periodontitis treatment incurred
significantly higher PMPM medical costs than enrollees who received gingivitis treatment, DMS, other
dental services, or no dental services (p < .001). DM, CAD, and CVD condition groups who received
periodontitis treatment had significantly lower retrospective risk scores (ERGs) than enrollees who
received gingivitis treatment, DMS, other dental services, or no dental services (p < .001).
Conclusion: This two-year retrospective examination of a large insurance company database revealed a
possible association between periodontal treatment and PMPM medical costs. The findings suggest that
periodontitis treatment (a proxy for the presence of periodontitis) has an impact on the PMPM medical
costs for the three chronic conditions (DM, CAD, and CVD). Additional studies are indicated to examine
if this relationship is maintained after adjusting for confounding factors such as smoking and SES.
Published: 16 August 2006
BMC Health Services Research 2006, 6:103 doi:10.1186/1472-6963-6-103
Received: 28 October 2005
Accepted: 16 August 2006
This article is available from: http://www.biomedcentral.com/1472-6963/6/103
© 2006 Albert et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0
),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Background
Systemic health is often associated with the condition of
the oral cavity, because many systemic diseases manifest
in the mouth. However, less is known about the connec-
tion between a diseased periodontium and the impact it
may have on systemic health. The concept that periodon-
tal disease is a localized condition that affects only the
teeth and the surrounding tissue and bone is being
increasingly questioned and examined. The connection
between a diseased periodontium and its impact on sys-
temic health is currently being investigated for many con-
ditions including cardiovascular diseases and diabetes.
About 50 percent of the adults in the United States have
gingivitis (gum inflammation), 35 percent have some
form of periodontitis, and 7 to 15 percent have severe per-
iodontal disease (inflammation of the gums leading to
destruction of the bone supporting the teeth) [1,2] conse-
quently, the association between periodontal infection
and systemic health has important implications for the
treatment and management of patients.
Cardiovascular disease is a leading cause of death within
the United States and accounts for 40 percent of all
deaths. Over 927,000 Americans die of cardiovascular dis-
ease each year, while over 70 million (over one-fourth of
the population) live with the condition. Coronary heart
disease is a leading cause of premature, permanent disa-
bility in the United States workforce. Health care expendi-
tures and lost productivity from death and disability due
to cardiovascular disease is projected to be $394 billion in
2005 [3].
A number of epidemiological studies have examined the
relationship between periodontal disease and vascular
disease [4-8]. Beck et al. analyzed data from a cohort study
and reported that the incidence odds ratios for alveolar
bone loss associated with severe periodontal disease and
total coronary heart disease, fatal coronary heart disease
and stroke were 1.5, 1.9, and 2.8 respectively. The
researchers concluded that an increased level of bone loss
was accompanied by a higher occurrence of heart disease,
which suggested an association between the two condi-
tions [4]. Genco et al. reported similar findings. In this
study, a group of Native Americans from the Gila River
Indian Community had their alveolar bone level and car-
diovascular status monitored prospectively over a period
of ten years. Among all age groups, the researchers found
that bone level was predictive of cardiovascular disease,
with an odds ratio of 2.68 in groups ≤ 60 years [6]. A cross-
sectional study conducted by Arbes et al., analyzed data
obtained from the National Health and Nutrition Exami-
nation Survey (NHANES III) to determine whether an
association between periodontal disease and coronary
heart disease could be found. Results from this study sup-
ported a periodontal disease/coronary heart disease con-
nection [8]. In two separate case-control studies Mattila et
al. compared patients with acute myocardial infarction
with a control group that was selected from the commu-
nity at random. The results from both studies indicated
that patients with acute myocardial infarction were found
to have poor oral conditions, while those in the control
group had better oral health [7]. The connection between
periodontal disease and cardiovascular disease appears to
be further supported by the findings from a study con-
ducted by DeStefano et al. This study, which followed its
subjects for fourteen years, included an examination of
several variables that included age, gender, systolic blood
pressure, total cholesterol levels, physical activity and per-
iodontal disease. Of the 10,000 subjects analyzed, the
researchers found that controlling for other variables
those with severe periodontal disease had a 25 percent
increased risk of developing coronary heart disease than
those who had only mild periodontitis [5]. Wu et al.,
examined the relationship between periodontal health
and its association with nonfatal or fatal cerebrovascular
accidents (CVA). The results of this cohort study, in which
data were obtained from the First National Health and
Nutrition Examination Survey (NHANES I) and from its
follow-up study, showed periodontitis to be a significant
risk factor for total CVA, particularly non-hemorrhagic
stroke [9]. Desvarieux et al found a direct relationship
between specific periodontal microbiota and subclinical
atherosclerosis [10].
In 2003 the United States Department of Health and
Human Services, Centers for Disease Control and Preven-
tion, reported that 18.2 million people in the United
States have diabetes mellitus and that each year an addi-
tional one million adults are diagnosed with the condi-
tion [11]. Diabetes is the sixth leading underlying cause of
death in the United States and has been estimated to cost
91.5 billion dollars annually in medical care and lost pro-
ductivity [12]. The prevalence of diabetes has increased 30
to 40 percent during the past two decades [13] and it is
expected that the number is likely to become larger as the
population grows older and obesity becomes an increas-
ing problem.
Evidence suggests that diabetes is associated with the
increased occurrence and progression of oral complica-
tions that include gingivitis, periodontitis, periapical
abscesses, and alveolar bone loss. Among the many oral
problems that can occur because of diabetes, the preva-
lence of severe periodontitis is significantly higher among
people with poorly controlled diabetes [14] to the extent
that periodontitis has been called the "sixth complication
of diabetes" [15]. The reason for the higher rates of perio-
dontal disease in people with diabetes is not completely
understood, but studies have reported that there is little
difference in the periodontal flora of people with and
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without diabetes, and suggest that the increased destruc-
tion of tissue among those with diabetes may be due to an
altered host susceptibility to periodontal pathogens medi-
ated by the accumulation of Advanced Glycation End
Products in the tissues, as well as microvascular changes
and perhaps impaired lipid metabolism [16-18]. Con-
versely, these data also suggest that the presence of perio-
dontal infection can adversely affect glycemic control in
people with diabetes and that there appears to be a bi-
directional relationship between the two conditions. The
exact nature of this relationship is not yet clear, but there
is evidence indicating that the management and treatment
of periodontal disease in patients with poorly controlled
diabetes may reduce their insulin requirements, and
improve glycemic control and overall metabolic balance.
Grossi et al. reported that adults with diabetes who
received dental cleanings in combination with systemi-
cally administered antibiotics showed a significant
improvement in their condition and a reduction in their
glycated hemoglobin [19]. The findings from a study con-
ducted by Taylor et al., also appears to support the con-
cept that the presence of periodontal disease can have an
adverse impact on glycemic levels in people who have dia-
betes. These data indicate that people with non-insulin-
dependent diabetes mellitus and severe periodontitis had
an increased risk of developing poor glycemic control
[20]. Stewart suggested that periodontal therapy was asso-
ciated with improved glycemic control in persons with
type 2 diabetes [21]. Rodrigues demonstrated that non-
surgical periodontal therapy improved glycemic control
in patients with type 2 diabetes [22]. A review of the liter-
ature that examined twelve studies conducted to deter-
mine the effects of treating periodontal diseases on
glycemic control, concluded that the presence of perio-
dontal disease can lead to poor glycemic control in
patients with diabetes and that treating their periodontal
disease could have a beneficial impact on glycemic con-
trol in those with type 1 or 2 diabetes [23].
In this study, dental and medical claims data from the
Aetna Integrated Informatics Data Warehouse were exam-
ined to determine if there were differences in total medical
costs for cardiovascular diseases [Coronary Artery Disease
(CAD), and Cerebrovascular Disease (CVD)], and diabe-
tes mellitus (DM) condition members receiving the fol-
lowing dental services: (1) periodontal treatment
(periodontitis or gingivitis); (2) regular dental mainte-
nance services (DMS); (3) other dental services; or (4) no
dental services. Claims for specific medical diagnoses
groups were extracted from the medical claims database
and dental procedure claims were taken from the dental
claims database.
Methods
The source of data for this report is Aetna's Data Ware-
house for all preferred provider organization insurance
members with dates of service from January 1, 2001 to
December 31, 2002. Members who were included in the
sample were selected if they had concomitant and contin-
uous medical and dental coverage in an Aetna Dental and
Medical product. Demographic information available
with this database included age and gender. Race/ethnic-
ity was not available for this dataset. In 2002, it was
reported in the United States that 71% of Whites, 42% of
Latinos, 50% of African Americans, 61% of Asians and
41% of American Indian/Alaskan Natives had employer-
sponsored health insurance [24]. Overall, females' made
up 52% of the total population. The mean age for mem-
bers with DM was 57.2 years, with CAD was 63.5 years,
and CVD was 68.5 years. The sample reflected overall
Aetna membership within the United States with 17%
from the Mid-Atlantic, 16% from the Northeast, 15%
from the North Central region, 14% from the Southeast,
12% from the Southwest, and 12% from the West. 14%
were not assigned to a region of the United States. Over
half (58%) of the medical membership at Aetna partici-
pates in a preferred provider organization (PPO) product
(8,360,093). General dentists (44,762) and periodontists
(6,491) participate in the Aetna PPO.
The sample was derived from a larger pool that included
1,171,122 unique medical members, and 1,105,030
unique dental members. 764,684 members with two
years of continuous dental and medical coverage were
potentially available. From this group 116,306 members
qualified for inclusion in the study. These members had at
least one of three chronic conditions: (1) diabetes melli-
tus (DM); (2) coronary artery diseases (CAD); and (3) cer-
ebrovascular diseases (CVD). These three groups were not
mutually exclusive (Table 1). The International Classifica-
tion of Diseases, 9
th
Edition (ICD-9) codebook was used
to define these conditions (Table 2) [25].
To evaluate the potential relationship between periodon-
tal disease treatment and chronic conditions all PPO
members were placed into one of the following mutually
exclusive categories, based on their utilization of dental
services: (1) members who had treatment for periodontal
disease, (periodontitis treatment or gingivitis treatment)
(2) members who had at least one dental maintenance
service (examination and preventative treatment), but no
periodontal treatment (DMS); (3) members with other
dental services (restorative, prosthetic, and surgical treat-
ment), but no dental maintenance services and no perio-
dontal services; and (4) members with no dental services
at all. The total medical per member per month (PMPM)
medical cost for each of these categories was calculated.
The American Dental Association's CDT-3 codebook was
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used to define these treatment categories (Table 3) [26].
The dental codes listed in the CDT-3 are treatment codes.
The CDT-3 codebook does not record disease status.
Codes from 4000–4999 encompass all periodontal treat-
ment procedures (Table 3). The periodontal treatment cat-
egory was then dichotomized into periodontitis or
gingivitis treatment. If no periodontitis treatment was
provided, the enrollees in the periodontal treatment
group were assigned to the gingivitis group.
Statistical analysis
To control for differences in the overall disease burden of
each group, a previously calculated retrospective risk score
utilizing Symmetry Health Data Systems, Inc. Episode
Risk Groups™ (ERGs) was obtained from the insurers'
data warehouse for each selected member for each year of
the study, and the average of these risk scores was calcu-
lated for each group [27-29]. ERGs use basic inputs such
as the diagnoses recorded on medical claims and demo-
graphic variables to predict health risk. A key feature of
ERGs is its use of episodes of care as markers of total
health burden risk rather than the diagnoses from individ-
ual medical encounters. By using episodes of care, the
focus is placed on the key information describing a
patient's underlying medical condition rather than the
individual services provided in its treatment [27]. The
individual average risk scores were used to determine the
relative risk of each group compared to the population
average, and then they were used to adjust the actual
PMPM medical cost at the member level. Using the aver-
age of these adjusted scores permitted the groups to be
compared with disease burden "adjusted out". The score
is calculated for each member in each year based on the
member's age, gender, and diagnosed conditions. The
score is proportional to the expected annual medical cost.
For example, if Member A has a score that is 10% higher
than Member B, then Member A would be expected to
have annual medical claim costs that are 10% higher than
Member B, all else being equal. Approximately 7% of the
sample was dropped because one or both of the retrospec-
tive risk scores was missing.
The differences between group means were tested for sta-
tistical significance using log-transformed values of the
individual total paid amounts. The two-sample t-test
assumes that the values being compared are normally dis-
tributed, and experience has shown that total paid
amounts for individuals are not normally distributed.
This is typical of medical costs, where medical costs
increase at a higher rate among those with greater illness
or more severe chronic conditions. When total paid
amounts are logged the result is reasonably close to a nor-
mal distribution, allowing the use of the t-test.
For each pair of groups, the first test performed deter-
mined whether the variances of the groups were signifi-
cantly different. If they were, the Satterthwaite test was
used to compare the means. If the variances were not sig-
nificantly different, the two-sample t-test was performed.
The comparisons used two-tailed tests.
Table 2: Chronic conditions and their associated ICD-9 diagnosis and procedure codes
a
Category Code Type ICD-9 codes
Diabetes ICD-9 diagnosis 250–250.93, 357.2, 362.0–362.02, 366.41
Coronary Artery Disease ICD-9 diagnosis 402–402.91, 410–414.9, 428–428.9, 429.0–429.2, 429.7–429.79, 440.0–440.9, 443.0–443.9, 444.0–
444.9
Cerebrovascular Disease ICD-9 diagnosis 433–437.19, 437.4–437.49, 437.6–437.69, 437.9–438.9
a
International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), Sixth Edition, U.S. Department of Health and Human
Services. Centers for Disease Control and Prevention, National Center for Health Statistics. Hyattsville, MD
Table 1: Number of members with specified conditions grouped by utilization of dental services (n = 116,306)
a
Chronic Condition
b
Periodontal
Treatment
c
Periodontitis
Codes
Gingivitis Codes Dental
Maintenance
Services (DMS)
d
Other Dental
Services
d
No Dental
Services
d
Diabetes (n = 51,560) 7,232 3,829 (7.4%) 3,403 (6.6%) 27,699 (53.7%) 1,473 (2.9%) 15,156 (29.4%)
Coronary Artery
Disease (n = 75,262)
9,882 4,783 (6.4%) 5,099 (6.8%) 42,990 (57.1%) 2,341 (3.1%) 20,049 (26.6%)
Cerebrovascular Disease
(n = 22,153)
2,564 1,109 (5.0%) 1,455 (6.5%) 12,367 (55.8%) 801 (3.6%) 6,421 (29.0%)
a
Data are cumulative for two-year period (2001 and 2002)
b
Chronic Condition categories are not mutually exclusive
c
Periodontal treatment includes all D4000–4999 codes (periodontitis and gingivitis)
d
Enrollees in the dental maintenance services, other dental services, or no dental services received no periodontal services in 2001 and 2002
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The Columbia University Institutional Review Board
reviewed the study protocol and determined it to be
exempt from review, because there was no interaction
with subjects, no intervention, and no private, identifiable
information was collected.
Results
Periodontal treatment was provided to 14% of members
with a DM diagnosis, 13.12% with a CAD diagnosis, and
11.5% with a CVD diagnosis. Less than 10% of the perio-
dontal patients were treated for periodontitis (as defined
in Table 1), during the two-year period that was examined
by this study. Approximately half of the patients within
the three chronic conditions had DMS procedures. Nearly
30% of each chronic condition group had no dental serv-
ices.
Overall 6.7% of the members were diagnosed with DM,
9.2% with CAD, and 2.9% with CVD. The mean age for
members with DM was 57.2 years, with CAD was 63.5
years, and CVD was 68.5 years. Of the female members
35.4% were diagnosed with DM, 33% with CAD, and
42.6% with CVD. The age and percent female for each of
the chronic conditions exhibited no significant variation
within the periodontal treatment categories, the DMS cat-
egory, or the no dental services category.
PMPM medical expenditures included all ICD-9 codes
that were billed for a member within a chronic condition
category (Table 4). The PMPM medical costs were paid as
per plan design of coverage. Table 4 displays for each
group, the average PMPM medical cost for all medical
(but not dental) services incurred during the two-year
period. PMPM medical expenditures for the DM, CVD,
and CAD groups with periodontitis treatment exhibited
significantly higher log adjusted PMPM medical costs
than for groups with gingivitis, DMS, other dental services
or no dental services (p < .001). The DM gingivitis treat-
ment group exhibited significantly higher log adjusted
PMPM medical costs than for groups with other dental
services (p = .033), or no dental services (p < .001). For the
cardiovascular conditions groups with gingivitis treat-
ment, a marginally significant difference in PMPM medi-
cal costs was found only for the CAD gingivitis group
compared to the other dental services group (p = .048). All
periodontitis treatment groups had significantly higher
PMPM medical costs when compared to gingivitis treat-
ment groups (p < .001).
The mean PMPM medical costs were skewed to the right
(towards higher costs). To normalize the data a log trans-
formation was conducted. After log transformation of the
data and application of Episode Risk Groups™ (ERG),
average retrospective scores were obtained for each of the
three chronic conditions (Table 5). The retrospective risk
for DM, CAD, and CVD groups with periodontitis disease
treatment were significantly lower (p < .001), when com-
pared to groups who had only DMS procedures, other
dental services or no dental services. A lower retrospective
risk was observed for DM, CAD, and CVD groups who had
periodontitis treatment than for those who had gingivitis
treatment only (p < .001).
In Table 6, the untransformed PMPM medical cost for
individuals are risk-adjusted using the average risk score
for each group, and these are log-transformed for the t-
test. The risk scores from Table 5 have been applied to the
PMPM medical expenses from Table 4 to produce risk-
adjusted PMPM medical costs. When the PMPM medical
costs were adjusted for risk, the costs for groups who
received periodontitis disease treatment were higher for
all three chronic conditions, when compared to members
who had only DMS procedures, other dental services or
no dental services (p < .001). DM, CAD, and CVD perio-
dontitis treatment groups had significantly higher
expenses than gingivitis treatment groups (p < .001). The
Table 3: Dental utilization classification and their associated CDT-3 treatment codes
a
Category Code
Type
CDT-3 codes
Periodontal Treatment
b
CDT-3 D4000 – D4999
Periodontitis Codes CDT-3 D4220, D4240, D4245, D4260, D4263, D4264, D4266, D4267, D4268, D4274, D4341, D4381
Gingivitis Codes CDT-3 All other D4000–D4999 codes
Dental Maintenance Services
(DMS)
c
CDT-3 D0120, D0150, D0180, D0210–0470, D1110–1205, D1330, D0140, D0160, D0170, D0472,
D1310–1320, D1351
All Other Dental Services
d
CDT-3 D5000–9974, D0473–0999, D1352–3999
a
CDT-3: Current Dental Terminology: Users Manual/American Dental Association. Version 2000, Chicago, Ill.: American Dental Association, 1999
b
Includes all codes related to periodontal treatment including scaling and root planing and periodontal surgical procedures
c
Includes examination and preventative treatment
d
Includes restorative and prosthetic treatment
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DM, CAD, and CVD risk adjusted gingivitis treatment
groups had significantly higher PMPM medical costs than
enrollees with other dental services, or no dental services.
Discussion
DM, cardiovascular diseases (CAD and CVD) and perio-
dontal disease are common in the population. The
observed associations between the diseases do not imply
that periodontal disease has a causal association with DM
or the cardiovascular diseases. Periodontitis, DM and car-
diovascular diseases share many risk factors, including
age, smoking, and SES. Any relationship observed may be
the result of confounding biases. The age of enrollees was
similar, however smoking, SES and other factors were not
available in this data set.
Although we know that the periodontitis treatment
groups did have periodontal disease, we do not know how
long they had the disease before their treatment or the
severity of their disease without sequential clinical exami-
nations. Since periodontal disease is a chronic condition
whose prevalence increases with age it is reasonable to
conclude that significant chronic periodontal disease bur-
den existed for the three chronic disease condition mem-
bers (DM, CAD, and CVD). Because CDT-3 coding is a
treatment system and does not list conditions we are not
able to assess overall dental disease burden or severity in
this retrospective study. It should be emphasized that
minimal demographic and social information (age and
sex only) was available for this population. Additional
investigation is warranted to examine periodontal health
indicators such as bleeding, and pocket depth.
Higher log transformed medical costs for the DM group
with periodontitis treatment were observed during the
two-year study period in comparison to all other dental
service groups or to the group with no dental services. The
DM periodontitis treatment group also exhibited signifi-
cantly higher PMPM medical costs when compared to the
gingivitis treatment group. Patients who receive periodon-
titis treatment would be expected to exhibit more bone
loss and inflammation compared to patients with gingivi-
tis [19-23]. Without intraoral periodontal examinations
and the examination of confounders such as smoking it is
difficult to explain the reason for the increase in medical
costs in groups with periodontitis. A contributory factor
Table 4: Total medical per member per month costs with specified conditions grouped by utilization of dental services
a
. Total medical
per member per month costs with specified conditions grouped by utilization of dental services
a,c
Diabetes Coronary Artery
Disease
Cerebrovascular
Disease
Periodontitis Codes $342.48 ($4.71) $481.64 ($4.97) $579.82 ($4.98)
Gingivitis Codes $361.95 ($4.58) $418.34 ($4.62) $475.62 ($4.53)
Dental Maintenance
Services (DMS)
b
$347.89 ($4.56) $416.64 ($4.58) $418.38 ($4.48)
Other Dental Services
b
$439.02 ($4.45) $489.89 ($4.51) $405.24 ($4.39)
No Dental Services
b
$387.93 ($4.44) $469.19 ($4.59) $485.35 ($4.54)
P-values for
Periodontitis Codes
Periodontitis Codes vs.
DMS
< .001 < .001 < .001
Periodontitis Codes vs.
Other Dental Services
< .001 < .001 < .001
Periodontitis Codes vs. No
Dental Services
< .001 < .001 < .001
P-values for Gingivitis
Codes
Gingivitis Codes vs. DMS 0.596 0.216 0.379
Gingivitis Codes vs. Other
Dental Services
0.033 0.048 0.157
Gingivitis Codes vs. No
Dental Services
< .001 0.486 0.716
P-values for
Periodontitis Codes vs.
Gingivitis Codes
Periodontitis Codes vs.
Gingivitis Codes
< .001 < .001 < .001
a
Data are cumulative for two-year period (2001 and 2002)
b
Enrollees in the dental maintenance services, other dental services, or no dental services received no periodontal services in 2001 and 2002
c
The log-transformed values are shown in parenthesis. The differences between group means were tested for statistical significance using the log
transformed values of the individual total paid amounts
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may be diminished glycemic control in patients in the DM
periodontitis treatment group when compared to the
other dental treatment groups.
The log transformed PMPM medical costs for the CAD
and CVD groups were higher for the groups with perio-
dontitis treatment than for all other dental service groups
or to the group with no dental services. Periodontitis has
been associated with thickening of arterial walls. Desvar-
ieux and colleagues observed an increase in carotid intima
thickening in patients diagnosed with periodontitis [10].
Periodontitis is a chronic disease that may affect the cardi-
ovascular system either through bacteria associated with
periodontal disease entering the circulation and directly
contributing to the accumulation of lipid containing
plaques on the inner most layer of the artery wall; or to
systemic factors that can alter the immunoinflammatory
process [4,5]. Hujoel et al., in an examination of the first
National Health and Nutrition Examination Survey
(NHANES) found that gingivitis was not associated with
CAD, while periodontitis was weakly associated [30]. For
gingivitis (no periodontitis treatment) groups no associa-
tion was found for unadjusted PMPM medical expendi-
tures (Table 4) in the CAD and CVD conditions compared
to the no dental services group, however the risk adjusted
gingivitis groups (Table 6) were associated with higher
costs.
Episode Risk Groups™ (ERGs) utilize "episodes of care" as
a marker of risk rather than the ICD-9 codes from the
medical encounter. The ERG provides a risk assessment of
the expected health care costs or utilization of a group of
individuals [29]. For DM and the cardiovascular disease
groups (CAD and CVD), PMPM medical costs were higher
in the periodontitis treatment group than the groups with
no dental services (p < .001). However, the calculated
ERG scores for the DM and cardiovascular disease groups
were significantly different in the opposite direction, with
less risk assigned to the periodontitis treatment group
than to the no dental services group (p < .001). It is possi-
ble that dentist discretion to treat or not treat existing per-
iodontal conditions was a confounding factor. Individual
dentist's knowledge of systemic conditions could influ-
ence treatment plans, recall patterns and the decision to
treat periodontal disease. It is plausible that individuals in
the periodontitis treatment groups differed from patients
who did not receive periodontal treatment on behavioral
factors such as health seeking behaviors. The predictive
ability of the ERG model can be limited for patients with
higher costs or chronic medical conditions such as those
described in this study [28]
.
It should be noted that both the unadjusted (Table 4) and
risk adjusted (Table 6) PMPM medical costs for the perio-
dontitis treatment groups were significantly higher than
Table 5: Episode Risk Group™ (ERG) scores for members with specified conditions grouped bu utilization of dental services
a,c
Diabetes Coronary Artery
Disease
Cerebrovascular
Disease
Periodontitis Codes 3.39 4.68 6.23
Gingivitis Codes 4.23 5.41 6.96
Dental Maintenance
Services (DMS)
b
4.18 5.51 7.06
Other Dental Services
b
5.41 6.67 8.29
No Dental Services
b
4.79 6.49 8.26
P-values for
Periodontitis Codes
Periodontitis Codes vs.
DMS
< .001 < .001 < .001
Periodontitis Codes vs.
Other Dental Services
< .001 < .001 < .001
Periodontitis Codes vs. No
Dental Services
< .001 < .001 < .001
P-values for Gingivitis
Codes
Gingivitis Codes vs. DMS 0.580 0.170 0.560
Gingivitis Codes vs. Other
Dental Services
< .001 < .001 < .001
Gingivitis Codes vs. No
Dental Services
< .001 < .001 < .001
P-values for
Periodontitis Codes vs.
Gingivitis Codes
Periodontitis Codes vs.
Gingivitis Codes
< .001 < .001 0.002
a
Data are cumulative for two-year period (2001 and 2002)
b
Enrollees in the dental maintenance services, other dental services, or no dental services received no periodontal services in 2001 and 2002.
c
Retrospective risk score
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the dental services treatment groups or no dental services
group for all three conditions (DM, CAD and CVD) (p <
.001). The unadjusted PMPM medical costs for the gingi-
vitis group compared to other dental services or no dental
services was significant for the DM condition only. After
risk adjusted all chronic condition gingivitis groups (DM,
CAD, and CVD) had significantly higher PMPM medical
costs than other dental services or no dental services
groups.
The need for treatment of periodontal disease in the gen-
eral population is underscored by the increasing preva-
lence of periodontal disease with age. The prevalence of
periodontal disease in the population from age 15–24
years is approximately 30%; this increases to over 70% in
the population from age 45–54 years. It is estimated that
at least 35% of the dentate U.S. adults aged 30 to 90 have
periodontitis, with 21.8% having a mild form and 12.6%
having a moderate or severe form [1,2].
There are a number of additional limitations that should
be considered when interpreting the findings from this
study. First, the data presented here are from members of
a large insurance carrier who had continuous medical and
dental PPO coverage for a two-year period (764,288
unique members), and they therefore may not represent
the overall insured population for this company.
Although all patients were PPO members there is some
variability within plans. This may have accounted for
some of the observed differences. Members who did not
maintain continuous coverage over the two-year study
period were not included in the analysis. Second, women
are underrepresented in this sample in all three chronic
conditions, and do not reflect the fairly equal distribution
of these diseases in the overall population. For example,
in the general population for heart disease the crude per-
cent for all types of disease are 11.4% for males and 10.7%
for females, for stroke 2.4% for males and 2.3% for
females, and for diabetes 7.0% for males and 6.2% for
females [31]. Third, the utilization of dental services by
the study sample was higher than the general population.
For example, 70.6% of the members with diagnosed dia-
betes saw a dentist, compared to 65.8% of adults reported
within 1995–1998 Behavioral Risk Factor Surveillance
Table 6: Risk-adjusted PMPM for members with specified conditions grouped by utilization of dental services
a, c
. Total medical per
member per month costs with specified conditions grouped by utilization of dental services
a,c,d
Diabetes Coronary Artery
Disease
Cerebrovascular
Disease
Periodontitis Codes $158.67 ($3.95) $161.63 ($3.89) $146.28 ($3.62)
Gingivitis Codes $ 134.57 ($3.60) $121.57 ($3.41) $107.36 ($3.07)
Dental Maintenance
Services (DMS)
b
$130.96 ($3.60) $118.75 ($3.36) $93.13 ($3.01)
Other Dental Services
b
$127.47 ($3.23) $115.52 ($3.10) $76.80 ($2.78)
No Dental Services
b
$ 127.26 ($3.35) $113.71 ($3.22) $92.40 ($2.94)
P-values for
Periodontitis Codes
Periodontitis Codes vs.
DMS
< .001 < .001 < .001
Periodontitis Codes vs.
Other Dental Services
< .001 < .001 < .001
Periodontitis Codes vs. No
Dental Services
< .001 < .001 < .001
P-values for Gingivitis
Codes
Gingivitis Codes vs. DMS 0.954 0.057 0.250
Gingivitis Codes vs. Other
Dental Services
< .001 < .001 < .001
Gingivitis Codes vs. No
Dental Services
< .001 < .001 0.017
P-values for
Periodontitis Codes vs.
Gingivitis Codes
Periodontitis Codes vs.
Gingivitis Codes
< .001 < .001 < .001
a
Data are cumulative for two-year period (2001 and 2002)
b
Enrollees in the dental maintenance services, other dental services, or no dental services received no periodontal services in 2001 and 2002.
c
The untransformed PMPMs for individuals are risk-adjusted using the average ERG score, and these are log-transformed for the t-test. The log
transformations immediately precede the t-tests.
d
The log-transformed values are shown in parenthesis. The differences between group means were tested for statistical significance using the log
transformed values of the individual total paid amounts
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System [32]. Caution should be used in generalizing find-
ings presented here to the insured population or to the
general U.S. population.
Conclusion
In this retrospective examination of patient data we found
periodontitis treatment groups had a lower retrospective
risk for their chronic condition (DM, CAD, or CVD), than
patients who did not have periodontitis treatment. There
is evidence that an individual's systemic condition can
affect their overall oral health, and a mounting body of
evidence that oral health, particularly periodontal status
can also affect an individual's general health status. It may
be reasonable, therefore, to recommend that examination
of the oral cavity be included in guidelines for care of
patients with DM, CAD and CVD, and that public health
programs and insurers work together to raise awareness of
the need for periodic dental visits for those members of
the population who have diabetes and cardiovascular dis-
eases. This was recognized in objective 5.15 of Healthy
People 2010, which calls for increasing the proportion of
people with diabetes who have at least an annual dental
examination [33].
Competing interests
Mary Conicella is an employee of Aetna. The researchers
and authors at Columbia University (David Albert, Don-
ald Sadowsky, Panos Papapanou, and Angela Ward) do
not receive remuneration from Aetna. The research was
supported by a grant from Aetna.
Authors' contributions
MC and DA carried out the project. DA, PP, MC, and DS
worked on the project plan, and interpretation of results.
AW contributed to the background section and reviewed
and edited the manuscript. All authors helped to draft the
manuscript and have approved the final manuscript.
Acknowledgements
The authors would like to thank Tim Allen, Janet L. Thomson, and John
Smolskis at Aetna Integrated Informatics, and Sharifa Williams at Columbia
University for their assistance with the analyses.
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