Prevalence of Metabolic Syndrome and Associated Factors among Hemodialysis Patients Monitored at the National Teaching Hospital , Hubert Koutoucou Maga in 2015

Introduction: Metabolic syndrome is one of the main risk factors of cardiovascular disease among hemodialysis patients. Objective: The main objective of this study was to determine the prevalence and factors associated with metabolic syndrome among hemodialysis patients in Cotonou in 2015. Patients and methods: It was a cross-sectional, descriptive and analytical study conducted from 05 October to 02 November 2015 at the National Teaching Hospital, Hubert Koutoucou Maga of Cotonou. All patients aged 18 years and above, regularly under hemodialysis for the past 3 months and who gave their informed consent were included in the study. Those excluded were: currently hospitalized hemodialysis patients, hemodialysis patients hospitalized in the last three months, hemodialysis patients whose general condition deteriorated or unable to answer the questionnaire. Metabolic syndrome was defined according to the International Diabetes Federation’s criteria. Factors associated with metabolic syndrome were sought using logistic regression in univariate analysis. Confidence intervals were calculated at 95% and alpha significance threshold at 5%. Outcomes: In total 165 patients were included in the study. Male predominance was observed, with 1.27 sex-ratios. Average age was 49.3 ± 12.9 years with extremes ranging from 18 to 78 years. Metabolic syndrome is observed among 46 patients undergoing hemodialysis or 27.9% prevalence rate. Factors associated with the metabolic syndrome in univariate analysis were: gender (p < 0.001), age (p = 0.007), body mass index (p = 0.029) and prior diabetes history (p = 0.011). Conclusion: Metabolic syndrome is common among hemodialysis patients. Early screening and fighting against associated How to cite this paper: Vigan, J., Alassani, A.S.C., Ahissou, M.M.A., Sabi, A.K., AssogbaGbindou, U., Attolou, V. and Djrolo, F. (2016) Prevalence of Metabolic Syndrome and Associated Factors among Hemodialysis Patients Monitored at the National Teaching Hospital, Hubert Koutoucou Maga in 2015. Open Journal of Nephrology, 6, 167-175. http://dx.doi.org/10.4236/ojneph.2016.64022 Received: October 25, 2016 Accepted: December 25, 2016 Published: December 28, 2016 Copyright © 2016 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access


Introduction
Chronic kidney disease is a real public health problem [1].Hemodialysis patients are faced with the risk of cardiovascular diseases which are the first cause of mortality among this population.Cardiovascular diseases' index varies from 25% to 60% among patients with chronic renal disease [2].These cardiovascular diseases claim 44% of deaths among hemodialysis patients [3].The risk of hemodialysis patients' death is 5 to 20 times higher compared to the general population [4].
Metabolic syndrome is an entity that brings together in the same individual, several metabolic abnormalities which predispose him to cardiovascular risks.Metabolic syndrome is itself one of the main risk factors for cardiovascular diseases [5].
In Benin, the prevalence of the metabolic syndrome among chronic hemodialysis patients is unknown.The factors associated with metabolic syndrome among these patients have not yet been identified.This justifies the interest in this study on the metabolic syndrome among hemodialysis patients at the National Teaching Hospital Hubert Koutoukou Maga (CNHU-HKM) of Cotonou.

General Objective
• Study metabolic syndrome among hemodialysis patients monitored in CNHU-HKM.

Specific Objectives
• Determine metabolic syndrome prevalence among patients undergoing hemodialysis.
• Identify factors associated with metabolic syndrome among hemodialysis patients.

Patients and Methods
It was a cross-sectional, descriptive and analytical study conducted from 05 th October to 02 nd November 2015 at the Nephrology-Hemodialysis University Clinic of The National Teaching Hospital, Hubert Koutoukou Maga of Cotonou.This National University Teaching Hospital is the referral hospital for the whole country.Nephrology-Hemodialysis University Clinic received 60 -80 new patients per year, which are then distributed mostly in other public or private dialysis centers of the country.
Patients included in the study were at least 18 years old, under hemodialysis for at least the past three months and who gave their informed consent.The following were excluded from the study: currently hospitalized hemodialysis patients, hemodialysis patients hospitalized in the last three months, hemodialysis patients unable to answer the questionnaire.
Metabolic syndrome was defined according to International Diabetes Federation (IDF) which includes the following components [13]: • Waist size or abdominal circumference is above or equal to 94 cm among men and above or equal to 80 cm among women, • Blood pressure is above or equal to 130/85 mmHg or specific treatment of hypertension, • Fasting plasma glucose above or equal to 1, 1 g/L or specific treatment, • Fasting triglyceridemia above or equal to 1, 50 g/L or specific treatment, • HDL cholesterol levels below 0.40 g/l among men or below 0.50 g/L among women or specific treatment.
Metabolic syndrome occurs with a patient if his/her waist size is high and associated with at least two other criteria [13].
The waist circumference was measured at the end of hemodialysis session, in sitting position, with a measuring tape, placed in the middle of the distance between the iliac crest and the lower costal margin, on the narrowest abdominal section.
Other variables sought were socio-demographic data (age, gender, profession, marital status); medical history (diabetes, hypertension); lifestyle (alcohol abuse, and level of physical activity), dialysis parameters (usual number of hours of dialysis per session, frequency of dialysis per week, type of arterio-venous fistula or catheter, duration under hemodialysis, percentage of urea reduction) and biological data.
Patients practicing less than 30 minutes of physical activity per day were considered as inactive.Otherwise, they were considered active.Anemia is defined by a rate of hemoglobin below 10 g/dl according kidney Disease Improving Global Outcome (KDIGO) guideline [14].Urea reduction percentage (URP) was calculated on the ratio of the difference between blood urea nitrogen before dialysis and the one after dialysis on blood urea nitrogen before dialysis multiplied by 100.The URP is considered as normal when it is above or equal to 60%.With regard to biological data, blood sampling was made for each patient at the beginning of one of the he-modialysis sessions in the morning.Associated factors were sought by using logistic regression in univariate analysis.Data entry and analysis were performed using Epi Data 3.1.P-value below 0.05 was considered significant.

General Characteristics of the Population
The study population comprised 165 hemodialysis patients.Male predominance was noted with 1.27 sex-ratio.Average age was 49.3 ± 12.9 years with extremes ranging from 18 to 78 years.Hypertension (HTA) was observed among 103 patients (62.4%).Arteriovenous fistula (AVF) was the privileged vascular access, and it was observed among 140 patients (84.8%).Average BMI of patients was 22.5 ± 6.8 kg/m² with extremes ranging from 14.5 to 62.14 kg/m 2 .Table 1 shows the general characteristics of hemodialysis patients.

Metabolic Syndrome Prevalence
Metabolic syndrome was observed among 46 hemodialysis patients or 27.9% prevalence.The average waist size of patients was 87.7 ± 12.4 cm with extremes ranging from 64 to 130 cm.Average systolic blood pressures was 147 ± 25.73 mmHg with extremes ranging from 81 to 234 mmHg and average diastolic blood pressure was 76.03 ± 19.06 mmHg with extremes ranging from 10 to 111 mmHg.Average HDL rate was 0.47 ± 0.14 g/L with extremes ranging from 0.10 to 0.87 g/l.Average triglyceridemia was 1.17 ± 0.75 g/L with extremes ranging from 0.30 to 5.92 g/L.Average glycemia was 0.97 ± 0.35 g/L with extremes ranging from 0.6 to 2.60 g/l.The most frequently metabolic syndrome criteria observed were blood pressure above or equal to 130/85 mm Hg (66.67%), followed by HDL hypocholesterolemia (45.5%).Table 2 shows metabolic syndrome prevalence and metabolic syndrome criteria among hemodialysis patients.

Factors Associated with Metabolic Syndrome
Factors associated with metabolic syndrome in univariate analysis were gender (p < 0.001), age (p = 0.007), body mass index (p = 0.029), and diabetes history (p = 0.011).Table 3 shows factors associated with metabolic syndrome among hemodialysis patients in univariate analysis.

Metabolic Syndrome Prevalence
In this study, the definition of metabolic syndrome is based on IDF criterion, which is a reliable definition of metabolic syndrome.It is the most used and practical in the sense that the excess abdominal fat estimated through waist size is considered as a vital criterion [13].
Vogt et al. observed among the general population varied metabolic syndrome 51%, 66.3%, and 75.3% respectively following the criteria of NCEP ATP III, IDF and harmonized criteria [20].
The most frequent metabolic syndrome criteria observed were high blood pressure followed by HDL hypocholesterolemia.Bonet et al. reported similar results with high blood pressure among 65% of hemodialysis patients and HDL hypocholesterolemia among 52.7% patients [11].

Factors Associated with Metabolic Syndrome
Gender was associated with metabolic syndrome, and female subjects were 2.6 times more exposed to the risk of developing metabolic syndrome (RC [95% CI] = 2.66 [1.56-4.55];p < 0.001).This same association was reported by Chen (p < 0.0001) who used as criteria for metabolic syndrome definition, NCEP-ATPIII [21].
In our study, age is associated with metabolic syndrome among hemodialysis patients

Table 1 .
General characteristics of hemodialysis patients monitored at CNHU-HKM in 2015.

Table 2 .
Prevalence and characteristics of metabolic syndrome components among hemodialysis patients monitored at CNHU-HKM in 2015.

Table 3 .
Factors associated with metabolic syndrome among hemodialysis patients monitored at CNHU-HKM in 2015 (univariate analysis).