Vol 43 # 3 September 2011 - Kma.org.kw

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Evaluation of Insulin Resistance by the Homeostasis Model Assessment ...
September 2011
salivary gland biopsy (p = 0.790) and HOMA-IR
values.
There were no statistically significant differences
between the HOMA-IR values and autoantibodies
such as rheumatoid factor (p = 0.241), anti-Ro (p =
0.710) and anti-La autoantibody (p = 0.476) positivity.
However, a statistically significant difference was
detected between ANA positivity and HOMA-IR
values (p = 0.016). Four patients with pSS had high
HOMA values ( > 2.7) and all these patients had ANA
positivity.
There was a positive correlation between HOMA
values and insulin levels as expected (p < 0.0001) and
also, there were no statistically significant differences
between the HOMA-IR values and fasting glucose,
triglyceride, HDL-C, LDL-C, Body Mass Index (BMI),
systolic and diastolic blood pressure. However,
a statistically significant positive correlation was
detected between HOMA-IR values and HDL-C levels
(R = 0.450 p = 0.009) (Table 3).
Table 3: Correlation between HOMA and laboratory tests
HOMA R p-value
Fasting glucose (mmol/l)
Fasting insulin (microU/l)
HbA1c (%)
Triglyceride (mmol/l)
Total Cholesterol(mmol/l)
HDL-C (mmol/l)
LDL-C (mmol/l)
0,069
0.857
0,146
-0,093
0,041
0,450
-0,168
0,693
0.05). pSS patients with ANA positivity
had lower LDL-C levels (p = 0.009).
In this study, patients who had not received
antimalarials showed higher levels of total cholesterol
(p = 0.042) and HDL-C (p = 0.01). There were no
statistically significant difference between antimalarial
therapy and the other biochemical parameters such as
HOMA values, insulin, LDL-C and triglyceride levels
(p > 0.05).
DISCUSSION
To the best of our knowledge, this is the first study
about insulin resistance in pSS. This study evaluated
insulin resistance by using HOMA method in a total
of 35 pSS patients. The major finding was that pSS
patients with ANA had significantly higher HOMA
values than ANA negative patients.
Also, lipid profile alterations were seen in patients
with pSS [14] . In this study, a statistically significant
positive correlation was detected between HOMA-
IR values and HDL-C levels. The patients with no
extraglandular involvement had higher levels of total
and LDL-C. Patients who had not received antimalarial
drugs showed higher levels of total and HDL-C. Lower
triglyceride levels were seen in only anti-La antibodies
positive patients. pSS patients with ANA positivity
had lower LDL-C levels.
There are a few studies about the clinical
significance of metabolic alterations in patient with
pSS. Experimental and clinical studies showed that
there are an association between pSS and diabetes [6,12] .
Binder et al studied 102 type-1 diabetic patients and
found anti-Ro antibody among 32% of the patients [12] .
The non-obese diabetic (NOD) mouse is a murine
model of diabetes that develops an exocrine disease
similar to human pSS [16] .
In our study, a statistically significant difference
was detected between ANA positivity and HOMA-
IR values (p = 0.016). Four patients with pSS had
high HOMA values ( > 2.7) and all these patients had
ANA positivity. Islet cell auto antigen 69 is present
in salivary and lachrymal glands and pancreatic beta
cell and tissue of the nervous system [17] . Winer et al
reported that elevated levels of autoantibodies to this
protein were frequently found in serum of patients
with pSS [18] . These autoantibodies may be responsible
for the HOMA-IR and ANA association.
In addition to diabetes, in a previous study, Lodde
et al described a differentiated serum lipid profile in
patients with pSS. They found that total cholesterol
levels were significantly lower in pSS patients with
anti-Ro and lower HDL-C levels were seen in patients
with anti-La [14] . Ramos-Casals et al stated that patients
with pSS showed negative correlation between
autoantibody production and cholesterol/HDL-C
levels [13] .
However, in our study, lower triglyceride levels
were seen in patients with anti-La antibodies
positivity but not other antibodies, and lower LDL-C
levels in pSS patients with ANA positivity (p = 0.009).
Adipose tissue has a pivotal role in inflammation,
releases several inflammatory and immune mediators
termed adipokines [9] . We can speculate that the role of
adipokines in inflammatory rheumatic diseases may
explain the lipid profile alteration in patients with
pSS.
As regards insulin resistance data in other
rheumatic diseases such as SLE, Zeng et al reported that
SLE patients with hyperglycemia were characterized
by insulin resistance and reduced pancreatic beta
cell function [9] Likewise, Tso et al and Parker et al
suggested that SLE is associated with an increased
prevalence of the metabolic syndrome and patients
also show evidence of increased insulin resistance [3,10] .
Likewise Shahin et al showed that early untreated RA
patients are characterized by a severe insulin resistant