Prevalence and determinants of peripheral arterial disease in children with nephrotic syndrome

Abstract

Peripheral arterial disease (PAD) is the least studied complication of nephrotic syndrome (NS). Risk factors which predispose children with NS to developing PAD include hyperlipidaemia, hypertension and prolonged use of steroids. The development of PAD significantly increases the morbidity and mortality associated with NS as such children are prone to sudden cardiac death. The ankle brachial index (ABI) is a tool that has been proven to have high specificity and sensitivity in detecting PAD even in asymptomatic individuals. We aimed to determine the prevalence of PAD in children with NS and to identify risk factors that can independently predict its development. A comparative cross-sectional study was conducted involving 200 subjects (100 with NS and 100 apparently healthy comparative subjects that were matched for age, sex and socioeconomic class). Systolic blood pressures were measured in all limbs using the pocket Doppler machine (Norton Doppler scan machine). ABI was calculated as a ratio of ankle to arm systolic blood pressure. PAD was defined as ABI less than 0.9. The prevalence of PAD was significantly higher in children with NS than matched comparison group (44.0% vs 6.0%, p < 0.001). Average values of waist and hip circumference were significantly higher in subjects with PAD than those without PAD (61.68± 9.1cm and 67.6± 11.2 cm vs 57.03 ± 8.3cm and 65.60± 12.5cm respectively, p< 0.005). Serum lipids (triglyceride, very low density lipoprotein, total cholesterol and low density lipoprotein) were also significantly higher in subjects with PAD than those without PAD [106.65mg/dl (67.8-136.7) vs 45.72mg/dl (37.7-61.3), 21.33mg/dl (13.6-27.3) vs 9.14mg/dl (7.5-12.3), 164.43mg/dl (136.1-259.6) vs 120.72mg/dl (111.1-142.1) and 93.29mg/dl (63.5-157.3) vs 61.84mg/dl (32.6-83.1), respectively p< 0.05]. Increasing duration since diagnosis of NS, having a steroid resistant NS and increasing cumulative steroid dose were independent predictors of PAD in children with NS; p< 0.05 respectively. With these findings, it is recommended that screening for PAD in children with NS should be done to prevent cardiovascular complications before they arise.

Fig 1. Prevalence of PAD in children with nephrotic syndrome compared with an apparently healthy comparative group.

Forty-four of hundred NS patients had peripheral arterial disease (ABI range 0.7–0.8) giving a prevalence rate of 44%.–Fig 1. The corresponding figures for the comparative group were six of hundred subjects with a prevalence rate of 6.0%. Thus the prevalence of PAD was significantly higher in participants with NS (p < 0.001).