The prevalence of metabolic syndrome among adult patients with chronic kidney disease: an overlooked problem in Sudan
Introduction
Chronic kidney disease (CKD) is a worldwide health problem ranging from mild to end-stage renal disease and is one of the leading causes of mortality. The prevalence of chronic kidney is about 15% worldwide (1-3). Older people are more prone to develop CKD due to aging related reduction in glomerular function and chronic illnesses such as hypertension and diabetes (4,5). Unfortunately, many patients are not aware of CKD due to the long asymptomatic phase of the disease (6). Early treatment of CKD is important to slow disease progression (7). The prevalence of metabolic syndrome (MetS) increases with the growing prevalence of chronic renal disease (8).
MetS is a group of metabolic risk factors strongly associated with a greater risk of developing cardiovascular disease and type 2 diabetes mellitus. Components of MetS include central obesity, hypertension, insulin resistance, and atherogenic dyslipidemia (9,10). Both lifestyle factors and genetic factors are involved in the pathogenesis of MetS (11). There is an association between MetS and kidney damage (12). However, the mechanism by which components of MetS cause kidney damage is not yet elucidated. High caloric diet, unbalanced nutrition, sedentary lifestyle, and obesity which are now common in both developed and developing countries, are the main risk factors of MetS and CKD (13). Components of MetS might play an etiologic role in CKD (13-17). However, components of MetS do not have equal contribution to the risk of CKD (7). The prevalence of the MetS is growing in the Middle East and sub-Saharan Africa (18).
To our knowledge, there was no published study about MetS in CKD in the Sudanese population. This study aimed to determine the prevalence of MetS and associated risk factors in adult Sudanese patients with CKD. We present the following article in accordance with the STROBE reporting checklist (available at https://jphe.amegroups.com/article/view/10.21037/jphe-22-4/rc).
Methods
Study design
This was a descriptive cross-sectional hospital-based study.
Study area and duration
The study was conducted at Ibn Sina specialized hospital in Khartoum, Sudan from October 2020 to January 2021. Ibn Sina specialized hospital was selected because it is a tertiary healthcare hospital that attract patients with CKD.
Study population
All patients who came to the referred clinic of Ibn Sina specialized hospital during the study period.
Inclusion criteria
All patients who accepted to participate in the study were included in the study.
Exclusion criteria
Patients who refused to participate in the study.
Sampling technique and sample size
All study participants who fulfilled the inclusion criteria were selected as the representative study sample. The total coverage of patients presenting to the referred clinic in the present period was decided and the sample size of the patients was estimated to be about 100.
Study variables
Study variables include dependent variables: demographical characteristics, age, gender, body mass index (BMI), and independent variables, which are the laboratory investigations.
Data collection
The data was collected by a comprehensive, structured closed-ended questionnaire that covers the study’s relevant aspects and variables. The data was collected by the authors themselves.
Anthropometric measurements
Weight and height were measured using calibrated equipment and standardized technique. Body mass index (BMI) was calculated by the following formula: weight in kilograms divided by height in meters squared. Waist circumference of the study participants was measured at the iliac crest highest point during minimal respiration.
Measurement of blood pressure (BP)
Two readings of BP were obtained using a mercury sphygmomanometer in the sitting position following rest for 10 minutes and the mean of the readings was used for analysis.
Measurement of fasting blood glucose (FBG), HDL-cholesterol and triglycerides (TG)
Blood samples were collected after overnight fasting for 8–10 hours for the measurement of fasting blood glucose (FBG), HDL-cholesterol (HDL-C) and TG. All the biochemical parameters were assayed on a Biosystem BTS350.
Definition of CKD
CKD is defined as either urinary albumin-creatinine ratio more than 30 mg/gram or estimated glomerular filtration rate (eGFR) less than 60 mL/min per 1.73 m2 body surface area (19).
Definition of MetS
Patients with CKD were diagnosed with MetS using the modified National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria (20). According to NCEP criteria, subjects who had three or more of the following were defined as having MetS: (I) abdominal obesity WC >102 cm in men and >88 cm in women; (II) systolic BP ≥130 mmHg or a diastolic BP ≥85 mmHg); (III) TG ≥1.7 mmol/L, (IV) HDL-C <1.03 mmol/L in men and <1.29 mmol/L in women; (V) FBG ≥5.6 mmol/L. The participants who currently reported using anti-diabetic or anti-hypertensive medication were counted as having diabetes or high BP respectively.
Data analysis
Data entered into the questionnaire and then transferred to SPSS version 25.0 for analysis. Descriptive analysis was performed for all study variables with mean and standard deviation for quantitative data and frequencies with proportions for qualitative data. These were presented in frequency tables with percentages and graphs.
Bi-variable analysis was done to determine the associations between the main outcome variable and the other relevant risk factors with Chi-square test (for categorical variables) and t-test (for quantitative variables) statistical tests. P value of 0.05 or less was considered significant.
Ethical approval
This study was approved by the Sudanese Medical Specialization Board (SMSB) and the Manager of Ibn Sina Teaching Hospital. Also, verbal consent was taken from the patients. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013).
Results
Sociodemographic factors of study participants
More than half (53%) of the study participants were more than 55 years old; females were (56%) of the study participants. The majority of patients (61%) were from Khartoum State (Table 1).
Table 1
| Population demographics | Study participants (N=100) | |
|---|---|---|
| % | N | |
| Age, years | ||
| 18–35 | 20 | 20 |
| 35–55 | 27 | 27 |
| ≥55 | 53 | 53 |
| Gender | ||
| Male | 44 | 44 |
| Female | 56 | 56 |
| Origin | ||
| North Sudan | 59 | 59 |
| East Sudan | 2 | 2 |
| West Sudan | 39 | 39 |
| Residence | ||
| Khartoum | 61 | 61 |
| Middle Sudan | 19 | 19 |
| North Sudan | 7 | 7 |
| West Sudan | 3 | 3 |
| Occupation | ||
| Employee | 16 | 16 |
| Workers | 28 | 28 |
| Housewives | 44 | 44 |
| Jobeless/Retired | 12 | 12 |
Distribution of components of MetS among study participants.
Nineteen percent of the study participants had MetS, frequency of high blood pressure, high FBG, high TG, low HDL, and high WC were 48%, 39%, 43%,53%, and 9%, respectively (Table 2).
Table 2
| Components of metabolic syndrome | Study participants (N=100) | |
|---|---|---|
| % | N | |
| MetS | 19 | 19 |
| High BP | 48 | 48 |
| High FBG | 39 | 39 |
| High TG | 43 | 43 |
| Low HDL | 53 | 53 |
| High WC | 9 | 9 |
MetS, metabolic syndrome; BP, blood pressure; FBG, fasting blood glucose; TG, triglycerides; HDL, high-density lipoprotein; WC, waist circumference.
Characteristics of study participants
More than half (62%) of the study participants presented with fatigue, and also more than half (63%) were suffering from anemia (Table 3).
Table 3
| Characteristics of metabolic syndrome | Study participants (N=100) | |
|---|---|---|
| % | N | |
| Fatigue | 62 | 62 |
| Anemia | 63 | 63 |
| Skin changes | 7 | 7 |
| HTN | 55 | 55 |
| DM | 55 | 55 |
| Family history of MetS | 20 | 20 |
| Smoking history | 26 | 26 |
| Alcohol consumption | 7 | 7 |
| Taking AHM | 66 | 66 |
| BMI >30 kg/m2 | 15 | 15 |
| eGFR, mL/min | ||
| ≥90 | 14 | 14 |
| 60–90 | 24 | 24 |
| 45–60 | 16 | 16 |
| 30–45 | 17 | 17 |
| 15–30 | 18 | 18 |
| <15 | 11 | 11 |
HTN, hypertension; DM, diabetes mellitus; MetS, metabolic syndrome; AHM, antihypertensive medications; BMI, body mass index; eGFR, estimated glomerular filtration rate.
More than half (55%) of the study participants had a history of hypertension, and a similar percentage had a history of diabetes mellitus; less than a third (20%) of the study participants had a family history of a similar condition.
Twenty-six percent of patients were smokers, and 66% of them were using antihypertensive medications. BMI of more than 30 kg/m2 was found in 15% of patients while eGFR between 60–89 mL/min was found in (24%) of the study participants (Table 3).
Test of associations
Using Chi-Square test, a statistically significant association was found between MetS and high blood pressure (with P=0.004), high TG (with P=0.000), high FBG (with P=0.000) (Table 4).
Table 4
| Factors | Patient without MetS | Patient with MetS | Total | P value |
|---|---|---|---|---|
| Age | 47±12 | 55±10 | 0.083 | |
| Gender | 0.785 | |||
| Male | 8 | 36 | 44 | |
| Female | 11 | 45 | 56 | |
| High BP | 14 | 34 | 48 | *0.040 |
| High FBG | 17 | 22 | 39 | *0.000 |
| High TG | 16 | 17 | 33 | *0.000 |
| Low HDL | 8 | 45 | 53 | 0.054 |
| High WC | 2 | 7 | 9 | 0.795 |
| Total | 19 | 81 | 100 |
*, significant P value. MetS, metabolic syndrome; BP, blood pressure; FBG, fasting blood glucose; TG, triglycerides; HDL, high-density lipoprotein; WC, waist circumference.
Discussion
Components of MetS are involved in CKD development (21). To the best of our knowledge, this is the first study in Sudan to assess the prevalence and associated risk factors of MetS in patients with CKD. In the present study, 19% of the participants had MetS. In the same direction, previous studies conducted by Ramli et al. (22), and Xiao et al. (23), reported that the percentages of the study participants with MetS were 23%and 25%, respectively. In contrast to our study, Poudel et al. (13) reported that 37.5% of their participants had MetS. The present study showed that more than a half (53%) of the study participants were more than 55 years old, similar to Ramli et al. (22) who reported that the mean age group of their participants was 40–60 years old. More than half (56%) of the study participants were females and male to female ratio was 1:1.3. In agreement with our study, Kurella et al. (24), revealed a male-to-female ratio of 1:1.2. Similar to Xiao et al. (23), our study found that more than half of the study participants presented with fatigue, and less than one third (15%) of the study participants had BMI of more than 30 kg/m2.
One interesting finding of our study is that more than half (59%) of study participants had a 88–100 cm waist circumference. Bener et al. estimated waist circumference in MetS to be 85–109 cm (25). In the present study, 61% of the participants had FBG level of less than 100 mg/dL, 57% of the study participants had a TG level of less than 150 mg/dL, and 53% of study participants had HDL level of less than 40 mg/dL, similar to Sawant et al. findings, which are components of MetS (26).
In agreement with Sheen et al., who investigated the association between MetS and renal diseases (27), the present study documented that more than half of patients (60%) of the study participants had an eGFR less than 60 mL/min. This is similar to Xiao et al. (23), who showed that more than half of their participants had eGFR of 60–89 mL/min.
The present study showed that the risk factors for MetS in adult Sudanese patients with CKD were hypertension, high FBG level, and hypertriglyceridemia, similar to a recent study conducted by Xu et al., which recruited 37,533 old Chinese individuals to investigate the association of components of MetS with CKD (28). Furthermore, Michishita et al. (29) and Lu et al. (7) reported that hypertension and hyperglycemia are associated with CKD. Zhao et al. showed that hypertriglyceridemia is associated with a higher risk of nephric microvascular damage and CKD (30). The main risk factor for MetS in our study was hypertension, while abdominal obesity was the main risk factor in Morocco and Nepal (13,21). It is worth mentioning that about one third of the population in the Middle East and sub-Saharan Africa is hypertensive (31). The high prevalence of hypertension in this study can be also explained by activation of the renin-angiotensin-aldosterone system and sympathetic nervous system, and inhibition of Atrial natriuretic peptide in patients with CKD (32).
This study is not without limitations. The sample size was relatively small and the cross-sectional design does not allow for identifying the temporal relationship between the risk factors and outcome. Variables that constitute the components of the MetS are associated with metabolic syndrome. The study might not truly represent all patients with MetS and CKD as the involvement of patients was not from all renal centers in Sudan. Despite all these limitations, this study is novel and reflects the prevalence and risk factors of MetS in adult Sudanese patients with CKD.
Conclusions
Nineteen percent of the study participants had MetS. The risk factors for MetS were hypertension, high FBG and high hypertriglyceridemia. The growing prevalence of MetS is expected to increase the prevalence of CKD. Components of MetS should be identified early and controlled in patients with CKD. Further clinical trials with bigger sample sizes should be conducted to establish whether the treatment of MetS or its components can improve the clinical outcomes in patients with CKD.
Acknowledgments
Funding: None.
Footnote
Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jphe.amegroups.com/article/view/10.21037/jphe-22-4/rc
Data Sharing Statement: Available at https://jphe.amegroups.com/article/view/10.21037/jphe-22-4/dss
Peer Review File: Available at https://jphe.amegroups.com/article/view/10.21037/jphe-22-4/prf
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jphe.amegroups.com/article/view/10.21037/jphe-22-4/coif). MHA serves as an unpaid editorial board member of Journal of Public Health and Emergency from August 2017 to July 2023. The other authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was approved by the Sudanese Medical Specialization Board (SMSB) and the Manager of Ibn Sina Teaching Hospital. Also, verbal consent was taken from the patients. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013).
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
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Cite this article as: Noor SK, Hamid S, Abdelgeyoom AE, ElSayed A, Ibrahim M, Abdelrahim HM, Eldin MS, Ahmed MH, Ahmed M. The prevalence of metabolic syndrome among adult patients with chronic kidney disease: an overlooked problem in Sudan. J Public Health Emerg 2022;6:13.
