Prevalence of Cardiovascular Risk Factors in Patients with ... - MedIND

ORIGINAL ARTICLE

JIACM 2009; 10(1 & 2): 23-6

Prevalence of Cardiovascular Risk Factors in Patients with Chronic Kidney Disease Sarathi Kalra*, Pralhad Sharma*, Acharya Pranab Sharma*, Sanjib Sharma**

Abstract Background: Chronic kidney disease (CKD) is a global health problem. Patients with CKD have accelerated atherosclerosis, and cardiovascular disease (CVD) is the most common cause of death in them. Objective: To estimate the prevalence of risk factors for CVD in patients with CKD. Material and methods: A nested case control study was conducted in patients evaluated for CKD over a period of 8 weeks attending the Renal Disease Prevention Clinic of BP Koirala Institute of Health Sciences, Dharan, Nepal. A total of 84 subjects (42 cases and 42 controls) were enrolled by convenient sampling method. The data collected were entered and analysed by SPSS, and odds ratios were calculated. Results: The mean age for cases and controls was 53.3 (SD ± 13.7) and 51.5 (SD ± 16.1) years respectively, and both groups were sex-matched. The prevalence of diabetes mellitus, hypertension, and smoking was higher among the cases (OR = 1.67, 2.16 and 3.67 respectively). Duration of diabetes and hypertension was longer in cases as compared to the controls. Besides this, smoking was more common in patients of CKD as compared to controls (OR = 3.67). The cases having sedentary lifestyle and haemoglobin level less than 12 g/dl were 54.8% and 55.2% respectively as compared to 43.6% and 21.1% in controls (OR = 1.5 and 4.0 respectively). Of the cases, 63.6% had altered lipid profile. Patients with CKD had a higher waist-to-hip ratio as compared to the controls. Conclusion: Patients with CKD have higher prevalence of risk factors for CVD. Key words: Cardiovascular disease, risk factors, chronic kidney disease.

Introduction Chronic kidney disease (CKD) is a worldwide public health problem. It is associated with significantly increased morbidity and mortality. Data show that approximately 40 to 75% of patients starting dialysis therapy already have manifestations of cardiovascular disease (CVD) and it accounted for 40% of subsequent deaths in these patients1,2. Based on such data, the National Kidney Foundation (NKF) Task Force has made the recommendation that patients with CKD should be considered in the highest risk group for the development of subsequent cardiovascular events3. Various studies have shown that this increased cardiovascular risk begins quite early during the course of renal insufficiency4. CVD risk factors involved in CKD may be classified as either traditional (viz. hypertension, diabetes mellitus, hyperlipidaemia, smoking, positive family history) or uraemia-related [viz. albuminuria, anaemia, oxidative stress, hyperhomocysteinaemia, raised lipoprotein (a)

levels]5. Several of these risk factors result in accelerated atherosclerosis, thereby leading to the increased prevalence of CVD. Most patients of CKD die of CVD rather than due to kidney failure6. Early interventions at correcting many of these risk factors may help decrease the cardiovascular morbidity and mortality in patients with CKD7. To the best of our knowledge, no study from Nepal has looked into various CVD risk factors in patients with CKD. The present pilot study was done to evaluate the prevalence of various CVD risk factors in CKD patients in Nepal.

Material and methods This study was conducted in the Renal Disease Prevention Clinic of the medical out-patient department of B. P. Koirala Institute of Health Sciences, Dharan, Nepal. It was a nested case control study. The study included 42 cases of CKD and 42 controls. Patients were enrolled by convenient sampling technique. CKD (case) was defined and staged as per the National Kidney Foundation – K/DOQI

* Intern, ** Additional Professor, Department of Internal Medicine, B. P. Koirala Institute of Health Sciences, Dharan, Nepal.

guidelines7. Those who were not found to have CKD or any major ailment were taken at random and grouped as controls. Patients with cerebrovascular accident, congestive heart failure, fever, and infection were excluded. An elaborate questionnaire was designed. Ethical clearance was obtained from the Ethical Committee of the Institute. Informed consent was taken from all the patients and controls before administering the questionnaire. Data from patients as well as controls were recorded on a pre-designed proforma. GFR was estimated using Cockcroft and Gault formula. Sedentary lifestyle was defined as less than 30 minutes of physical exercise per day for at least 5 days a week. Truncal obesity was defined as waist-to-hip ratio > 0. 9 for males and > 0.8 for females. Laboratory investigations included urinalysis, haemoglobin, blood urea, serum creatinine, blood sugar, lipid profile and other tests, as required.

Results Out of the total 84 subjects, there were 42 cases with male to female ratio of 1: 1 and 42 controls with male: female ratio of 1.1:1. The mean age of cases and controls was 53.3 (± 13.7) and 51.5 (± 16.1) years respectively. The prevalence of diabetes mellitus and hypertension was significantly higher in cases than the control group (OR = 1.67 and 2.16 respectively). Besides this, the prevalence of smoking was found to be more common in cases as compared to controls (OR – 3.67). Prevalence of sedentary lifestyle and anaemia was 54.8 and 55.2% in cases compared to 43.6 and 21.1% respectively in the control group (OR = 1.5 and 4.0 respectively). Similarly, deranged lipid profile and truncal obesity were also more common in the cases. Table I shows the prevalence of various CVD risk factors in cases and controls.

Discussion Patients with CKD are more likely to die of CVD than to develop kidney failure6. The alarming rise in CKD appears not to be due to intrinsic renal disease but to the dramatic rise in systemic diseases that damage the kidney. These include type 2 diabetes and atherosclerotic disease8. Patients with CKD have an increased risk for major cardiovascular morbidity and mortality9. Such increased cardiovascular risk begins quite early in renal insufficiency4. CKD and CVD share a number of common

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aetiological factors. Moreover the circumstances derived from disease in one system cannegatively influence the other organ system10. Buteven after adjusting for such factors, the association of CKD with prevalence of cardiovascular disease is seen to persist11.This prompted the American Heart Association in 1993 to recommend that patients with CKD be considered members of the “highest risk group” for development of subsequent cardiovascular events12. As CVDin CKD is treatable and potentially preventable, assessment of major risk factors prevalent in resource poor settings like ours becomes important. We found a higher prevalence of diabetes mellitus in the CKD group as compared to the control population (OR = 1.67). Truncal obesity as well as deranged lipid profile was higher among CKD group in both the sexes than the control group. It is important to realise that these factors are treatable and potentially preventable, mostly with simple lifestyle modifications. Measures like physical exercise, dietary modification and smoking cessation could potentially have highly favourable outcomes and minimise the CVD risk factors. Among our cases 54.8% had a sedentary lifestyle whereas smokers were also higher among cases (OR = 3.67). Awareness, health promotion and lifestyle modification seem to be the most effective and economically sound interventions to control these factors in developing countries. Our findings show a higher prevalence of hypertension in the cases than the controls (OR = 2.16). Early detection and institution of anti-hypertensive therapy is the key factor. This has been specifically stressed by Joint National Committee (JNC-7) which includes CKD as a “compelling” indication, justifying lower target blood pressure and treatmentwith specific anti-hypertensive agents13. Anaemia (haemoglobin < 12 g/dl) was observed in 55.2% of cases compared to 21.1% of the controls (OR = 4.0). This uraemia-related risk factor shares a close relationship between cardiovascular morbidity and mortality14. Data from Medicare considered anaemia a multiplicative risk factor for mortality in patients with CKD15. It is also associated with causation of cardiomyopathy14, 16. Proteinuria, reduced GFR and creatinine clearance are other independent risk factors for development of CVD.

Journal, Indian Academy of Clinical Medicine

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Majority (31% each) of the patients were in stage 2 and 3 and only 7% were in stage 5, indicating that increased CVD risk develops quite early during the course of renal insufficiency4. Recent evidence shows that even modestly raised albuminuria values, within what hitherto has been considered the normal range, are associated with a future risk of CV events17-19. Possibly the glomerular albumin leak reflects a widespread atherosclerosismediated capillary vasculopathy affecting the cardiovascular system alike20-22.

realistic strategy to avert national health and economic crisis. Structured and well-resourced primary and secondary prevention programmes based on reducing the risk factors for chronic kidney disease and cardiovascular disease could make a big difference, both for CKD and subsequent CVD risk. An effort has been initiated in Nepal through ISN supported KHDC-Nepal programme by conducting ‘door-to-door’ screening programmes for chronic diseases and risk factors for cardiovascular disease.

Table I: Demographic and lipid profile of the study population. Cases (n = 42)

Controls (n = 42)

53.3 1:1

51.5 1.1:1

Diabetes mellitus duration (yrs) 10

23 11 (47.8%) 2 (8.7%) 10 (43.5%)

15 8 (56.3%) 3 (18.8%) 4 (24.9%)

Hypertension duration (yrs) 10

27 16 (59.3%) 4 (14.8%) 7 (25.9%)

16 7 (43.8%) 7 (43.8%) 2 (12.4%)

+ve history of smoking. If yes, then pack years < 10 > 10

21 (50.0%) 9 12

9 (21.4%) 3 6

3.67

Sedentary lifestyle

23 (54.8%)

18 (43.6%)

1.5

Haemoglobin (< 12 g/dl)

23 (55.2%)

9 (21.1%)

4.0

0.99 1.00

0.95 0.96

Mean age (yrs) Sex M: F

Waist: Hip Ratio Male Female Dyslipidaemia

63.6%

It is thus quite evident that there exist various CVD risk factors among CKD patients within our setting also. Clear guidelines have been proposed for risk stratification, like the JNC-7 for lower target blood pressure, and NKF-K/ DOQI guidelines for a lower target low-density lipoprotein cholesterol level. For a developing country like ours with limited resources and the huge financial burden of renal replacement therapy, preventive strategies should be emphasised. Development of strategies for early detection and prevention of kidney involvement and control of risk factors for CVD is the only


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Odds ratio

1.67

2.16

23.8% 3.4

There are certain limitations of this case control study; namely, this study is a hospital-based pilot study and the results cannot be extrapolated at the community level. Hence, large scale community-based studies will give a better reflection of the burden of cardiovascular risk factors in CKD patients. The present study highlights that in the Nepalese population the prevalence of various cardiovascular risk factors in patients with CKD is significantly higher. Some of these risk factors such as hypertension, smoking, obesity, and sedentary habits are potentially modifiable. Thus appropriate changes in

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lifestyle and timely treatment of hypertension and diabetes can help in significant reversal of cardiovascular risk profile, thereby decreasing the morbidity and mortality in patients with chronic kidney disease.

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