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May 2007, Volume 57, Issue 5

Original Article

Frequency of the metabolic syndrome in adult type2 diabetics presenting to Pakistan Institute of Medical Sciences

Abdul Mohsin  ( Departments of General Medicine, The Children's Hospital, Pakistan Institute of Medical Sciences, Islamabad )
Jamal Zafar1  ( Departments of General Medicine, The Children's Hospital, Pakistan Institute of Medical Sciences, Islamabad )
Sayed Muhammad Imran  ( Departments of General Medicine, The Children's Hospital, Pakistan Institute of Medical Sciences, Islamabad )
Kashif Zaheer  ( Departments of General Medicine, The Children's Hospital, Pakistan Institute of Medical Sciences, Islamabad )
Bushra Khizar  ( Departments of General Medicine, The Children's Hospital, Pakistan Institute of Medical Sciences, Islamabad )
Rizwan Aziz Qazi  ( Departments of General Medicine, The Children's Hospital, Pakistan Institute of Medical Sciences, Islamabad )
Yasir Bin Nisar  ( Departments of ARI Research Cell2, The Children's Hospital, Pakistan Institute of Medical Sciences, Islamabad )

Abstract

Objective: To determine the frequency of metabolic syndrome in both genders, in a limited adult type 2 diabetic population presenting to Pakistan Institute of Medical Sciences, Islamabad.

Methods:
This was a cross sectional study conducted in a tertiary care teaching hospital. During the six months of study period, 106 adult type2 diabetics were examined and evaluated for the presence of metabolic syndrome according to the ATP-III criteria. Asian standards for the waist circumference were used.

Results:
Out of 106 patients, 91 (85.8%) had metabolic syndrome of whom 95% were females. Abdominal obesity was present in 91% females and 86% males. Low HDL levels were present in all females and 83% males. Seventy eight percent females and 63% males had elevated levels of triglycerides. Hypertension was present in 68% and 73% females and males respectively.

Conclusion:
This study showed a very high prevalence of the metabolic syndrome in type2 diabetic population. Females were more affected than males in all respects (JPMA 57:235;2007).

Introduction

The association between diabetes, obesity and hyperlipidaemia is long known and has been termed "insulin resistance syndrome", syndrome"X" and metabolic syndrome by various researchers.1 This syndrome is recognized as constellation of metabolic risk factors for the development of type2 diabetes mellitus and atherosclerotic cardiovascular disease (ASCVD).2 In 2001, the National Cholesterol Education Program (NCEP) Expert Panel on
Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel-III or ATP-III) suggested a working definition for the metabolic syndrome that included abdominal obesity, atherogenic hyperlipidemia, high blood pressure and impaired glucose tolerance.3 Taken individually, each component of the metabolic syndrome is a well established risk factor for the ASCVD. These factors act synergistically and increase the risk for ASCVD from two to three folds.4

With growing problem of obesity in the modern world, a high prevalence of metabolic syndrome is observed. Findings from the National Health and Nutrition Examination Survey (NHANES) in USA suggested an unadjusted and age adjusted prevalence of 21.8% and 23.7% among US adults respectively.2 The age adjusted prevalence in an Indian urban population was reported as 24.9%.5

The prevalence is higher among diabetics than non-diabetics and is reported as 70-80% among Caucasian type 2 diabetics.6,7 A study conducted in Indian urban population gives a prevalence of 76.3% among type-2 diabetics.8 Prevalence of diabetes in Pakistan is high and studies suggest that more than 12% of Pakistani adults above 25 years of age have diabetes.9 Rapid urbanization and acquisition of western life style have resulted in decreased physical activity and increased calorie intake; two of the major contributors towards the development of diabetes and metabolic syndrome.3 The exact prevalence of metabolic syndrome in Pakistan is not known, though United States census department has given an estimate of approximately 25% among general population.10

The recent Adult Treatment Panel (ATP III) guidelines have called specific attention to the importance of targeting the cardiovascular risk factors of the metabolic syndrome as a method of risk reduction therapy. Since the presence of metabolic syndrome and diabetes together poses a greater risk for the development of ASCVD than either alone, it is important to know the prevalence and pattern of metabolic syndrome among diabetics. This is necessary for the effective prevention of ASCVD among this particularly high risk group. We conducted this cross sectional study to determine the frequency of metabolic syndrome in a limited adult type 2 diabetic population and its differences between the two sexes.

Methods

This cross sectional study was conducted at Pakistan Institute of Medical Sciences, Islamabad, which is the largest tertiary care hospital in the northern half of Pakistan. Majority of the patients come from upper Punjab, North Western Frontier Province and Kashmir, as well as the city and suburbs of Islamabad. The hospital has a diabetes clinic on outpatient basis for the routine follow-up and monitoring of these patients.

During the study period of six months from January to June 2005, we enrolled a total of 106 adult type2 diabetics above 20 years of age who presented to the diabetic clinic or were admitted to the medical ward for glycaemic control.

All type1 diabetics as well as young type2 diabetics (age <20 years) were also excluded from the study. Patients with renal failure, Cushing syndrome or with ascites due to any reason were excluded. Patients with secondary hypertension, hepato-biliary disease and hypothyroidism were excluded from the study after thorough clinical evaluation. For nephrotic syndrome as an exclusion criterion, massive proteinuria was also required. Patients taking lipid-altering drugs were also not included.

Specifically designed forms were used to collect the data. Informed consent was taken after fully explaining the procedure and objective of the study. Demographic and clinical data, including ischaemic heart disease (evidenced by history of angina pain, myocardial infarction or coronary artery surgery); family history of diabetes, ischaemic heart disease and hypertension were recorded.

World Health Organization (WHO) criteria were used for the diagnosis and classification of diabetes mellitus.11 Samples for blood glucose and serum lipid profile were taken after an overnight fast. Samples were analyzed on the Selectra E Vitalab analyzer by enzymatic colorimetric method.

Sitting blood pressure was measured with mercury sphygmomanometer, using the patient's right arm and after 10 minutes of rest. Two readings were taken and the mean was used for analysis.12 Waist circumference was measured at the level of the mid point between the high point of the iliac crest and last rib on the sides and the umbilicus anatomy, using a tape measure with the person lightly clothed.13 A waist circumference of =88 cm (for females) or =102 cm (for males) constitutes central obesity in Caucasian populations.3 The NCEP/ATP III criteria for abdominal obesity in a slams was used and metabolic syndrome was defined according to the cut-offs of waist circumferences > 90 cm in men and > 80 cm in women.14

[(0)]

Metabolic Syndrome was diagnosed using the ATP III criteria (Table 1).
Data was entered and analyzed by using SPSS version 11 software. Demographic indicators and different parameters for metabolic syndrome recorded at the time of enrollment were analyzed. Descriptive analysis was done and reported as mean, standard deviation and median for continuous variables and frequencies and percentages for categorical variables.

Results

During the study period, 106 known cases of type2 diabetes mellitus were enrolled. Of these 106, 91 (85.8%) were diagnosed to have metabolic syndromoe. Of the 64 female patients, 61 (95.3%) had the metabolic syndrome whereas 30 (71.4%) of 42 males fulfilled the criteria of the syndrome. This difference was statistically significant (p=0.001).

The mean (standard deviation) age of all the metabolic syndrome patients was 49.7 (11.1) years. Thirty (32.9%) patients were between the age group 41 to 50 years. The family history of diabetes, obesity and ischaemic heart disease were present in 47 (51.6%), 38 (41.8%) and 25 (27.5%) patients respectively. Only 16 (17.6%) patients were smokers.
The mean (standard deviation) duration of diagnosis of diabetes was 6.5 (5.7) years. Forty six (50.5%) patients had it for less than 5 years. Majority (74.7%) of patients were currently treated with oral hypoglycemic agents. In 42 (46.2%) patients all the five risk factors for the metabolic syndrome were present. However in 15 (16.5%) patients only 3 risk factors were present. The baseline characteristics are shown in Table 2.

[(1)]
[(2)]

The comparison of various risk factors for diabetic metabolic syndrome in both sexes is shown in Figure. Our result showed that abdominal obesity was present in 91% female and in 86% male patients. However all female and 83% males had low HDL levels. Seventy eight percent females and 63% males had elevated levels of triglycerides. Hypertension was present in 68% and 73% females and males respectively.

Discussin

We studied 106 patients with type-2 diabetes mellitus using the ATPIII criteria. The study estimated a prevalence of 85.8%, which is very high. Studies conducted in other parts of the world estimated a prevalence of 70-80% among Caucasian type-2 diabetics6 and 75.6% among Chinese population with type-2 diabetes mellitus.15 An Indian population based study using the Caucasian criteria for abdominal obesity, gave a prevalence of 76.3% among type2 diabetics.8

Different studies report quite varied effects of gender on the metabolic syndrome in different populations. In USA, metabolic syndrome is more prevalent in white males than in females.16 In American blacks, Mexican Americans, Korea, Iran, India, Oman, and Kinmen women had higher prevalence of the metabolic syndrome than men.17-20 We observed that metabolic syndrome was more common in females with type-2 diabetes mellitus as compared to their male counterparts (p-value 0.001). The higher percentage is also reported in Nigerian women with type-2 diabetes mellitus.21 The reason may be a relatively sedentary lifestyle of women, in this part of the world, due to religious and social barriers.

Prevalence of the metabolic syndrome tends to increase with age.21,22 However, we did not find a statistically significant difference in the ages of both groups.
Family history of hypertension, type-2 diabetes mellitus and obesity are recognized markers of genetic predisposition to the syndrome.23 Our study supports this fact as more patients with the syndrome had a family history of obesity and diabetes in the first degree relatives as compared with those without the metabolic syndrome.

We further categorized our patients with metabolic syndrome into three groups according to the number of metabolic risk factors present. The majority of patients were those who had all the five risk factors followed by those having four and three respectively. This trend is almost similar to that found in the Nigerian diabetic population.21

Finally, the prevalence of different risk factors in patients of both sexes with metabolic syndrome was studied. As all of the patients were diabetics, males and females were compared for the presence of abdominal obesity, hypertension, low HDL and high triglycerides levels. We found low HDL levels and abdominal obesity as the two most prevalent risk factors in both sexes. An interesting finding was that all of the females with metabolic syndrome had low HDL levels. The combination of abdominal obesity and dyslipidemia was also reported as the most common combination among Chinese type-2 diabetics with metabolic syndrome.24 Abdominal obesity is reported as one of the most prevalent risk factor among patients with metabolic syndrome in Greece.25

In Kinmen, the most common abnormalities were high blood pressure in men and large waist circumference in women.17 In the Iranian population, low HDL cholesterol was the most common metabolic abnormality in both sexes.18 In western India, the prevalence of low HDL cholesterol was 90.2% in women and 54.9% in men.19 Thus, it appears that low HDL cholesterol and large waist circumference are responsible for the high prevalence of metabolic syndrome in women in many populations.

Conclusion

Metabolic syndrome has been underestimated in our setup and not much importance is laid on its consequences. This limited observational study showed a very high prevalence of the metabolic syndrome in type2 diabetic population. There is a need to conduct a study involving a larger population and to make recommendations for the primary and secondary prevention of this syndrome.

References

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