Prevalence of cardiovascular risk factors
in patients with psoriasis
Andrea L. Neimann, MD,a,bDaniel B. Shin, BA,aXingmei Wang, MS,bDavid J. Margolis, MD, PhD,a,b
Andrea B. Troxel, ScD,band Joel M. Gelfand, MD, MSCEa,b
Background: Previous studies suggest that patients hospitalized for psoriasis have an increased frequency
of a variety of cardiovascular comorbidities. Limited population-based data exist on this association, and
few studies have determined which factors are independently associated with psoriasis.
Objective: We sought to determine whether the prevalence of the major cardiovascular risk factors was
higher in mild and severe psoriasis than in patients without psoriasis.
Methods: We conducted a population-based study in the United Kingdom using the General Practice
Research Database. Patients were classified as having severe psoriasis if they received a code for psoriasis as
well as systemic therapy. Patients were defined as having mild psoriasis if they ever received a psoriasis code
but no systemic therapy. Control subjects were selected from the same practices and start dates as psoriasis
patients. Patients were classified as having risk factors if they received codes for diabetes, hypertension,
hyperlipidemia, obesity, or smoking. Analyses were performed by using conditional logistic regression, and
adjustments were made considering age, gender, person-years, and all cardiovascular risk factors.
Results: We identified 127,706 patients with mild psoriasis and 3854 with severe psoriasis. Respective
prevalence rates of risk factors in those with severe psoriasis, mild psoriasis, and in controls were as
follows: diabetes (7.1%, 4.4%, 3.3%), hypertension (20%, 14.7%, 11.9%), hyperlipidemia (6%, 4.7%, 3.3%),
obesity (20.7%, 15.8%, 13.2%), and smoking (30.1%, 28%, 21.3%). Patients with mild psoriasis had a higher
adjusted odds of diabetes (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.08-1.18]), hypertension (OR,
1.03; 95% CI, 1.01-1.06), hyperlipidemia (OR, 1.16; 95% CI, 1.12-1.21), obesity (OR, 1.27; 95% CI, 1.24-1.31),
and smoking (OR, 1.31; 95% CI, 1.29-1.34) than controls. Patients with severe psoriasis had a higher
adjusted odds of diabetes (OR, 1.62; 95% CI, 1.3-2.01), obesity (OR, 1.79; 95% CI, 1.55-2.05), and smoking
(OR, 1.31; 95% CI, 1.17-1.47) than controls. Additionally, diabetes (OR, 1.39; 95% CI, 1.22-1.58) and obesity
(OR, 1.47; 95% CI, 1.32-1.63) were more prevalent in those with severe psoriasis than with mild psoriasis.
Limitations: The study was cross-sectional and therefore the directionality of the associations could not be
Conclusion: Multiple cardiovascular risk factors are associated with psoriasis. Cardiovascular risk factors
that are key components of the metabolic syndrome are more strongly associated with severe psoriasis than
with mild psoriasis. ( J Am Acad Dermatol 2006;55:829-35.)
and its incidence peaks in early adult life (20s) and
then again in later adult life (50s and 60s).3-6Clinical
manifestations of psoriasis are heterogeneous, rang-
ing from limited disease to very extensive disease.
and there may be periods of remissions and exacer-
bations. The majority of patients (approximately
80%) have limited disease (eg, \2% body surface
area [BSA]), whereas approximately 20% of patients
have more extensive skin involvement (eg, [3%
soriasis is a common chronic immune-
mediated disease that affects 1% to 3% of
the population.1-3It affects people of all ages,
From Dermatologyaand the Center for Clinical Epidemiology and
Biostatistics,bUniversity of Pennsylvania.
Supported by grant K23 AR051125-01 from the National Institutes
of Health and the National Institute for Arthritis, Musculoskel-
etal, and Skin Diseases (to J. M. G.).
Conflicts of interest: None identified.
Accepted for publication August 20, 2006.
Reprint requests: Joel M. Gelfand, MD, MSCE, Department of
Dermatology, University of Pennsylvania, 3600 Spruce St, 2
Maloney Bldg, Philadelphia, PA 19104. E-mail: joel.gelfand@
Published online September 26, 2006.
ª 2006 by the American Academy of Dermatology, Inc.
BSA).7Despite the fact that psoriasis carries minimal
risk of mortality, it is associated with significant
morbidity and has substantial economic costs to
of psoriasis on quality of life may be significant even
if relatively limited BSA is involved.9
The pathophysiology of psoriasis is characterized
by increased antigen presentation, increased cuta-
neous T lymphocyte activity, and the up-regulation
of type 1 helper T cytokines.10-12The etiology of
psoriasis is a complex disorder caused by the inter-
action of multiple genes, the immune system, and
environmental factors. Although few environmental
factors have been definitively linked to chronic
ing and an elevated body mass index (BMI) may be
risk factors for the development of psoriasis.13
Smoking and obesity are associated with psoriasis
and are also established cardiovascular risk factors.14
the literature suggest a high prevalence of cardio-
vascular risk factors (eg, diabetes, hypertension, and
hyperlipidemia) as well as cardiovascular disease
(CVD) in psoriasis patients.15-23A major limitation of
most of these studies is that they focus on highly
for their disease. Since patients with multiple comor-
bidities (including smoking and alcohol use) are
more likely to be hospitalized, these studies may
have been limited by selection bias.24Additionally,
none of these studies performed multivariable mod-
eling to determine which cardiovascular risk factors
may be independently associated with psoriasis.
The goal of our investigation was to perform a
broadly representative population-based study to
determine whether the prevalence of the major car-
diovascular risk factors identified by the Framingham
studies was higher in patients with mild and severe
psoriasis than in patients without psoriasis. We also
aimed to determine whether these risk factors were
independently associated with both mild and severe
This was a cross-sectional (prevalence) study
with data collected by general practitioners (GPs)
in the United Kingdom (UK), who were participating
in the General Practice Research Database (GPRD)
between 1987 and 2002. GPs were unaware of the
hypothesis to be tested. The data were collected
as part of the patient’s electronic medical record
and are maintained in the GPRD. GPRD contains
data on more than 9 million persons with more than
35 million person-years of follow-up time and is
UK system of care, the GP is responsible for manag-
specialists, and the information from the specialist
is captured electronically by the GP.26GPs receive
specific training, financial inducements, and penal-
ties to ensure accuracy of the data. GPRD has been
used extensively for epidemiologic studies. The
validity of using the GPRD to study psoriasis and
diseases associated with cardiovascular disease has
been demonstrated previously.1,26-30
The study population consisted of all psoriasis
patients who had at least one day of observation
time, as described previously.31Each psoriasis pa-
tient was matched to up to 5 subjects (as available
based on matching criteria) who did not have pso-
riasis, who were seen in the same practice, and who
had a date of observation in the practice (the max-
imum of the date when the patient registered with
the practice and the date when the practice was
designated ‘‘up to standard’’) within 60 days. Prac-
tices are designated as being ‘‘up to standard’’ when
audits demonstrate that at least 95% of relevant
patient encounters are recorded and the data are
determined to be of suitable quality for epidemio-
logic research. The matching was performed to
ensure that patients were followed up in the same
practice and time periods to minimize the impact of
secular and geographic differences between those
with and without psoriasis. The analyses were re-
stricted to patients 20 to 90 years of age as cardio-
vascular risk factors are very rare in patients younger
than 20 years, which diminished the number of
eligible controls for this study.
Definition of prevalence
Prevalence is defined as the proportion of indi-
viduals in a population who have the disease of
interest in a specified time period. Our definition of
prevalence approximates lifetime prevalence as any
GPRD: General Practice Research Database
JNK:c-Jun amino-terminal kinase
OR: odds ratio
TH1: type 1 helper T cells
TNF: tumor necrosis factor
body mass index
body surface area
J AM ACAD DERMATOL
830 Neimann et al
documentation of psoriasis or cardiovascular risk
factors (diabetes, hypertension, hyperlipidemia,
smoking, increased BMI) by the GP at the time the
patient was registered in the practice would result in
the patient being classified as having these diseases.
In addition, documentation of these diseases could
occur at any time that the patient was followed up in
the practice over the 5 to 6 years of observation time.
Study time period
For all patients, observation start-time was the
dates. Follow-up time ended when patients died,
transferred out of the practice, or the practice was no
longer ‘‘up to standard’’ (whichever came earliest).
Definition of psoriasis
Diseases are classified in the GPRD using Oxford
Medical Information System and Read codes. Oxford
Medical Information System and Read codes are
diagnostic codes that GPs use as part of the patient’s
electronic medical record. Patients were classified as
having psoriasis if they ever received a diagnostic
code for psoriasis by the GP that has been validated
ogy of psoriasis in GPRD is very similar to other
population-based studies in the United Kingdom,32
and more than 90% of patients with a psoriasis
diagnostic code receive psoriasis therapies.1Addi-
tionally, when directly querying a random sample
of 100 GPs who had entered a diagnostic code of
psoriasis, in approximately 90% of cases the GPs
confirmed that psoriasis was still the diagnosis after 4
years of follow-up.28Psoriasis patients were defined
code consistent with severe disease (eg, psoralen,
ine, etretinate, acitretin, hydroxyurea, mycopheno-
late) during the entire study time period. Treatments
consistent with severe psoriasis were determined by
the British National Formularyand theopinion oftwo
dermatologists (D. J. M., J. M. G.). Psoriasis patients
were classified as having ‘‘mild’’ disease if they
received a code for psoriasis but never received a
prescription code consistent with severe disease dur-
ing the study period. Patients were classified as not
havingpsoriasis (eg,control population) iftheynever
received a diagnostic code consistent with psoriasis.
Definition of cardiovascular risk
Patients were classified as having a cardiovascular
risk factor if they received a medical code consistent
with diabetes, hypertension, hyperlipidemia, or cur-
rent smoking at any time during the study period.
The BMI was determined by weight and height
calculations or from documentation in the patient’s
electronic medical record.
The data were summarized descriptively. The
prevalence rates of cardiovascular risk factors in
the psoriasis groups were first compared with those
in the nonpsoriasis population using unadjusted
conditional logistic regression modeling, which
accounted for matching factors of practice and dif-
ferences in observation time. The rates were then
adjusted for age, sex, and person-years of observation
to yield prevalence odds ratios. To test the indepen-
dent association of individual cardiovascular risk
factors with both mild and severe psoriasis, we also
performed multivariable conditional logistic regres-
sion modeling, adjusting for each of the individual
risk factors (diabetes, hypertension, hyperlipidemia,
smoking, BMI) in addition to age, sex, and person-
years. All statistical analyses were performed using
Protection of study subjects
Data utilized for this study were stripped of
personally identifiable information. The study was
approved by the Office of Regulatory Affairs of the
University of Pennsylvania and by the Scientific
and Ethical Advisory Group of the Medicines
Control Agency, United Kingdom. The study was
conducted in concordance with the Declaration of
We identified 127,706 patients with mild psoriasis
who were matched with 465,252 subjects without
psoriasis and 3854 patients with severe psoriasis
matched to 14,065 corresponding subjects without
psoriasis (Table I). Psoriasis patients were slightly
older than matched control patients and were more
likely to be male than the controls. In addition,
person-years of observation were slightly greater in
both psoriasis groups compared with their respec-
tive control groups (Table I). Information on BMI
was available for 61% of patients.
In unadjusted analyses, patients with mild and
severe psoriasis were more likely to be current
smokers and have diabetes, hypertension, hyperlip-
idemia, and increased BMI compared with controls
(Table I). Patients with mild psoriasis had increased
odds of having each of the cardiovascular risk factors
that persisted (Table II) when adjusting for age,
gender and person-years (diabetes: odds ratio [OR]
1.27, 95% confidence interval [CI] 1.23-1.31; hyper-
tension: OR 1.16, 95% CI 1.14-1.18; hyperlipidemia:
J AM ACAD DERMATOL
VOLUME 55, NUMBER 5
Neimann et al831
OR 1.28, 95% CI 1.24-1.33; smoking: OR 1.4, 95% CI
1.38-1.43; BMI 25-30: OR 1.12, 95% CI 1.10-1.14; BMI
[30: OR 1.29, 95% CI 1.26-1.32). The OR of mild
psoriasis after adjusting for age, gender, person-
years, and each of the other comorbidities (Table III)
remained statistically significantly elevated in pa-
tients with diabetes (OR 1.13, 95% CI 1.08-1.18),
hypertension (OR 1.03, 95% CI 1.01-1.06), hyperlip-
idemia (OR 1.16, 95% CI 1.12-1.21), elevated BMI
(BMI 25-30: OR 1.12, 95% CI 1.10-1.14; BMI[30: OR
1.27, 95% CI 1.24-1.31), and who were current
smokers (OR 1.31, 95% CI 1.29-1.34); however, the
magnitude of the association was small for hyper-
tension. Similar results were obtained via sensitivity
analysis in which we ensured that all patients were
seen at least twice by GPs and that their end of
observation time coincided with a GP visit (to ensure
that all patients were actively followed up) (data not
shown). Additionally, similar results were found
when performing a sensitivity analysis in which we
performed the multivariable model (except the BMI
variable) in the entire patient sample (data not
shown). Finally, similar results were found in a sen-
sitivity analysis that included a history of myocardial
infarction, indicating that the cardiovascular risk fac-
psoriasis patients because psoriasis is associated with
CVD (eg, myocardial infarction) (data not shown).
In analysis of severe psoriasis, there was a statis-
tically significant association (Table II)between each
of the individual cardiovascular risk factors and
severe psoriasis after adjusting for age, gender, and
person-years (diabetes: OR 1.86, 95% CI 1.58-2.19;
hypertension: OR 1.25, 95% CI 1.13-1.39; hyperlip-
idemia: OR 1.31, 95% CI 1.11-1.56; elevated BMI
(BMI 25-30: OR 1.28, 95% CI 1.15-1.43; BMI[30: OR
1.84, 95% CI 1.60-2.11); current smokers: OR 1.31,
95% CI 1.20-1.44). This association persisted in the
Table I. Description of study groups
Variable Control—mildMild Control—severeSevere
Mean (median, 25th, 75th)
465,252 (78.46) 127,706 (21.54) 14,065 (78.49)3,854 (21.51)
45.7 (42, 30, 60)
46.4 (44, 31, 60)
46.34 (43, 31, 61)
49.8 (49, 37, 63)
BMI, Body mass index.
*BMI was available in 61% of patients.
Table II. Prevalence odds ratios of individual
cardiovascular risk factors in mild and severe
psoriasis versus controls
model (95% CI)*
model (95% CI)*
BMI, Body mass index; CI, confidence interval.
*Model adjusted for age, sex, person-years.
yBMI was available in 61% of patients.
Table III. Prevalence odds ratios of individual
cardiovascular risk factors in patients with mild
and severe psoriasis versus controls
model (95% CI)*
model (95% CI)*
1.00 (0.87-1.14) NS
1.04 (0.84-1.28) NS
BMI, Body mass index; CI, confidence interval; NS, not statistically
*Model adjusted for age, sex, person-years, diabetes, hypertension,
hyperlipidemia, smoking, and BMI.
yBMI data were available in 61% of patients.
J AM ACAD DERMATOL
832 Neimann et al
case of diabetes, increased BMI, and current smok-
ing after adjusting for age, gender, person-years, and
all cardiovascular risk factors (Table III); however,
the association was attenuated and no longer statis-
tically significant in patients with hypertension (OR
1.00, 95%CI 0.87-1.14) and hyperlipidemia(OR 1.04,
95% CI 0.84-1.28). Similar results were obtained via
sensitivity analyses that excluded patients treated
with cyclosporine and oral retinoids (to ensure that
therapies that have been associated with hyperten-
sion and hyperlipidemia did not solely account for
reported associations between severe psoriasis and
these comorbidities) (data not shown) and in which
we assured that all patients were seen at least twice
by GPs and that their end of observation time
coincided with a GP visit (to ensure that all patients
were actively followed up) (data not shown). Addi-
tionally, similar results were found in performing
a sensitivity analysis in which we used the multivar-
iable model (except the BMI variable) in the entire
found in a sensitivity analysis that included a history
of myocardial infarction, indicating that the cardio-
vascular risk factors were not necessarily more likely
to be identified in severe psoriasis patients because
severe psoriasis is associated with cardiovascular
disease(eg,myocardial infarction) (data not shown).
The strongest associations with severe psoriasis in
both adjusted analyses were with diabetesand obesity
(BMI[30). In addition, these two diseases were more
with mild psoriasis when adjusting for age, gender,
obesity: OR 1.47, 95% CI 1.32-1.63) (Table IV).
The results of this study suggest that diabetes,
hypertension, hyperlipidemia, smoking, and in-
creased BMI are associated with both mild and
severe psoriasis. Additionally, these diseases are all
independently associated with mild psoriasis; how-
ever, except for obesity and smoking, the association
was negligible to modest for most of the cardiovas-
cular risk factors and therefore unlikely to be of
clinical significance. The association with severe
psoriasis when controlling for traditional cardiovas-
cular risk factors persists in the case of diabetes,
smoking, and increased BMI (especially BMI [30
[obesity]), but in the case of hypertension and
hyperlipidemia the association is attenuated, sug-
gesting that these latter two diseases are not inde-
pendently associated with severe psoriasis. In
addition, patients with severe psoriasis were more
likely to have each of the cardiovascular risk factors
we studied compared with patients who had mild
psoriasis, with the magnitude of association being
strongest for obesity, diabetes, and hypertension.
These results suggest that psoriasis is associated
with the complex disorder of metabolic syndrome,
which incorporates hypertension, dyslipidemia, obe-
sity, and impaired glucose tolerance, and that the
association is stronger for severe psoriasis compared
with mild psoriasis.33
Similar to psoriasis, the metabolic syndrome is
characterized by increases in the immunological
activity of type 1 helper Tcells (TH1), which suggests
the hypothesis that psoriasis may be associated with
the metabolic syndrome because of shared inflam-
matory pathways.34For example, circulatory levels
of tumor necrosis factor (TNF)-a, soluble TNF-a
receptors, and in vitro TNF-a production have been
shown to be elevated in patients with components of
the metabolic syndrome, such as obesity and insulin
resistance.34,35TNF may lead to insulin resistance by
inhibiting insulin-mediated tyrosine phosphoryla-
tion of the insulin receptor as well as insulin receptor
substrate-1, key to downstream insulin signaling and
glucose transportation to the cell surface.36Further-
more, TNF-a has also been shown to be a potent
activator of c-Jun amino-terminal kinase (JNK),
which stimulates activator protein-1, a major regula-
tor of proinflammatory activity. Mouse models show
that JNK activity is abnormally elevated in obesity
and that the absence of the JNK1 molecule is asso-
ciated with decreased adiposity, improved insulin
sensitivity, and enhanced insulin receptor signal-
ing.37Therefore it is possible that the association of
the diseases which characterize the metabolic syn-
drome and psoriasis is explained by dysregulation of
TH1 pathways shared by these seemingly disparate
diseases. Another explanation for the predisposition
of psoriasis patients to develop metabolic syndrome
may be that certain behaviors or the psychological
impact of psoriasis itself (eg, poor eating habits,
alcohol consumption, stress, decreased exercise due
Table IV. Prevalence odds ratios of individual
cardiovascular risk factors in severe versus
Variable Psoriasis model (95% CI)*
BMI, Body mass index; CI, confidence interval.
*Model adjusted for age, sex, person-years.
yBMI data were available in 61% of patients.
J AM ACAD DERMATOL
VOLUME 55, NUMBER 5
Neimann et al833
to psoriasis symptoms or stigmatization) may lead
to development of increased body weight and the
metabolic syndrome. Lastly, the metabolic syndrome
itself could predispose an individual to developing
psoriasis as observed by a case-control study in
which increased BMI (a precursor to the metabolic
syndrome) was an independent risk factor for devel-
oping psoriasis (BMI 26-29: OR 1.6, 95% CI 1.1-2.1,
age, sex, marital status, hospitalization, education
level, smoking, and alcohol use).
Our study also confirms several previous reports
that psoriasis is associated with smoking.3Nicotine
alters a wide range of immunological functions,
Nicotine can modulate the functional capacity of
dendritic cells and can increase the secretion of
proinflammatory TH1 cytokines bydendriticcells.40,41
Studies support the hypothesis that nicotine alters
the immune response by directly interacting with
Tcells and dendritic cells as well as indirectly through
brain-immune interactions.42Additionally, nicotinic
cholinergic receptors have been demonstrated on
keratinocytes that stimulate calcium influx and
accelerate cell differentiation; they can also control
keratinocyte adhesion and upward migration in the
epidermis.43This suggests a biologic explanation for
the association between smoking and psoriasis.
Our study advances the literature of the associa-
tion of psoriasis and cardiovascular risk factors. To
our knowledge, this study is the only broadly repre-
sentative population-based study to date examining
the prevalence of these combined cardiovascular
risk factors with psoriasis. Additionally, our study
examined patients with both mild and severe psori-
asis and utilized multivariable modeling to deter-
mine which factors are independently associated
with psoriasis. The study is broadly representative of
all psoriasispatients; therefore the findingslikely can
be generalized to the general population of patients
Observational studies may be limited by bias and
confounding. Selection bias is unlikely to explain the
results described herein because the psoriasis
patients and control subjects were identified and
included from the same well-defined source popu-
lation. Information (ascertainment) bias is unlikely
to explain the results because psoriasis patients and
control subjects had information collected in the
same manner (ie, by GPs matched by practice), and
the results were robust to sensitivity analysis in
which we ensured that all patients were actively
followed up. Completeness of data may be an issue
in epidemiologic studies. Information on BMI was
available in our study for about 61% of patients,
which could affect generalizability. However, we
thought this unlikely as our full multivariable anal-
ysis (adjusting for age, sex, person-years, and each
of the cardiovascular risk factors except for BMI) in
our entire study population was comparable to our
analysis of only our population in which data on
BMI were captured. Furthermore, we measured
smoking status as ‘‘current’’ or ‘‘never’’ and therefore
could not determine whether history of smoking or
number of cigarettes smoked introduced any poten-
tial confounding. In addition, we defined severe
psoriasis based on a history of having received
systemic therapies; therefore we cannot differentiate
between the impact of psoriasis severity and sys-
temic therapy. The most commonly used systemic
therapy was methotrexate, and to our knowledge
methotrexate has no known association with diabe-
tes, hypertension, hyperlipidemia, or smoking. Oral
retinoids and cyclosporine may induce certain car-
diovascular risk factors such as hypertension and
hyperlipidemia in some patients; however, our find-
ings in the severe psoriasis group were robust to
sensitivity analyses, which excluded patients treated
with cyclosporine and oral retinoids. We also did not
directly assess psoriasis activity in our mild psoriasis
group, which is likely heterogeneous; therefore it is
possible that the association with cardiovascular risk
factors in those we classified as having mild psoriasis
varies on the basis of psoriasis activity (eg, extent of
skin involvement). Finally, since the diagnosis of
psoriasis was based on GP diagnosis, it is possible
that some patients with mild psoriasis did not in fact
have psoriasis. In the event that misclassification of
psoriasis occurred, we believe this would bias our
results toward the null, thus making our positive
findings even stronger.
The findings of this study are important and add
to the growing evidence that diabetes, hypertension,
hyperlipidemia, smoking, and increased BMI are
associated with psoriasis. In particular, the results
of this study demonstrate that psoriasis is associated
psoriasis compared with those with mild psoriasis.
This finding is important since those with as little as
one or two metabolic syndrome risk factors are at
increased risk for death caused by CVD.44Therefore,
as part of good medical care, patients with psoriasis
should be encouraged to identify and manage their
modifiable cardiovascular risk factors.
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