Prevalence of peripheral arterial disease among chronic kidney disease patients at Kenyatta National Hospital

Abstract

Background Chronic kidney disease (CKD) is a worldwide public health problem. There is a high prevalence of cardiovascular disease (CVD) in patients with CKD contributed to by presence of both traditional and non-traditional cardiovascular (CV) risk factors. Peripheral arterial disease (PAD) is a distinct atherothrombotic syndrome that is associated with an elevated risk of cardiovascular and cerebral events including myocardial infarction, stroke and death. The ankle-brachial index (ABI) is a simple, non-invasive, inexpensive and reliable measurement to assess the patency of the lower extremity arterial system with a sensitivity of 95% and specificity of 100%. Objectives The aim of the study was to determine the prevalence of PAD and the associated cardiovascular risk factors among patients with CKD at the Kenyatta National Hospital. Design Imethods Hospital based cross-sectional prevalence study Setting Kenyatta National Hospital Renal Clinic. Subjects Adult patients ~30 years with chronic kidney disease defined as proteinuria for ~3 months and or a GFR </= 60 ml/min/1.73 m2. Outcome measures • Prevalence of PAD. • Prevalence of selected CV risk factors in patients with CKD and PAD: - age, male gender, hypertension, cigarette smoking, dyslipidemia and diabetes mellitus. • Relationship between the selected CV risk factors and PAD. • Proportion of patients with symptomatic PAD. Results Between January and October 2006, 194 patients with CKD were studied, 111 males and 83 females. The underlying aetiology of CKD was diabetes in 34%, hypertension in 29%, chronic glomerulonephritis in 29%, obstructive uropathy in 6% and polycystic kidney disease in 2%. The mean GFR was 36 ± 24.7 (range 1.9 - 110.1 mllmin/1.73m2 ) with 81.4% of the patients having advanced CKD. Twenty-three patients had ABI <0.9 computing to a PAD prevalence of r- 11.9%(95% CI, 7.3- 16.4). The mean age of PAD patients was significantly higher than non-PAD counterparts (67.7 ±14.3yrs versus 50.5 ±13.6; p=O.OOO). PAD patients had a worse renal function compared to non-PAD patients (GFR 27.2 ± 21 versus 37.3 ± 25 ml/min/1.73m2, p=0.04). All but five of the PAD patients were male and all females were aged over 55yrs. All the PAD-patients demonstrated presence of traditional CV risk factors with the majority having more than two risk factors. The commonest risk factor was age occurring in 87% followed by male gender 78%, hypertension 74%, diabetes mellitus 56%, cigarette use 47% and dyslipidemia 43%. The odds ratios for cigarettes use, male gender, diabetes mellitus and CKD stage <3 versus CKD stage <3 were on average two fold, however only the male gender and diabetes mellitus attained statistical significance. Hypertension and dyslipidemia in this data set were not associated with the presence of PAD. On basis of the Edinburgh Claudication Questionnaire, 47.8% of PAD patients exhibited intermittent claudication. Conclusions The prevalence of PAD in CKD patients at KNH was 11.9%. All the selected CV risk factors were prevalent in the PAD population in varying proportions. Of the CV risk factors assessed, male gender and diabetes mellitus were independently associated with PAD. More than half of the patients with PAD were asymptomatic.