Baseline characteristics and prevalence of cardiovascular disease in newly visiting or referred chronic kidney disease patients to nephrology centers in Japan: a prospective cohort study

Abstract

Background: About 39,000 patients were newly prescribed renal replacement therapy in Japan in 2011, resulting in a total of more than 300,000 patients being treated with dialysis. This high prevalence of treated end stage kidney disease (ESKD) patients is an emergent problem that requires immediate attention. We launched a prospective cohort study to evaluate population specific characteristics of the progression of chronic kidney disease (CKD). In this report, we describe the baseline characteristics and risk factors for cardiovascular disease (CVD) prevalence among this cohort.

Methods: New patients from 16 nephrology centers who were older than 20 years of age and who visited or were referred for the treatment of CKD stage 2-5, but were not on dialysis therapy, were recruited in this study. At enrollment, medical history, lifestyle behaviors, functional status and current medications were recorded, and blood and urine samples were collected. Estimated glomerular filtration rate (eGFR) was calculated by a modified three-variable equation.

Results: We enrolled 1138 patients, 69.6% of whom were male, with a mean age of 68 years. Compared with Western cohorts, patients in this study had a lower body mass index (BMI) and higher proteinuria. The prevalence of CVD was 26.8%, which was lower than that in Western cohorts but higher than that in the general Japanese population. Multivariate analysis demonstrated the following association with CVD prevalence: hypertension (adjusted odds ratio (aOR) 3.57; 95% confidence interval (CI) 1.82-7.02); diabetes (aOR 2.45; 95% CI 1.86-3.23); hemoglobin level less than 11 g/dl (aOR 1.61; 95% CI 1.21-2.15); receiving anti-hypertensive agents (aOR 3.54; 95% CI 2.27-5.53); and statin therapy (aOR 2.73; 95% CI 2.04-3.66). The combination of decreased eGFR and increased proteinuria was also associated with a higher prevalence of CVD.

Conclusions: The participants in this cohort had a lower BMI, higher proteinuria and lower prevalence of CVD compared with Western cohorts. Lower eGFR and high proteinuria were associated with CVD prevalence. Prospective follow up of these study patients will contribute to establishment of individual population-based treatment of CKD.

Figure 1

Prevalence of individual causes of cardiovascular disease (CVD) stratified by CKD stages, the CKD-ROUTE study (Oct 2010 - Dec 2011). Angina pectoris (AP), myocardial infarction (MI), peripheral arterial disease (PAD) and stroke were highest in patients with stage 4 CKD; congestive heart failure (CHF) incidence gradually increased with CKD progression.

Figure 2

Prevalence of cardiovascular disease (CVD) in 11 categories classified by CKD stages and proteinuria, the CKD-ROUTE study (Oct 2010 - Dec 2011). Odds ratio (OR) was adjusted for age and gender. The reference category is the group with stage 2 and optimal proteinuria. Horizontal lines indicate 95% confidence intervals (95% CI) and the scales are logarithmic. eGFR lower than 30 ml/min per 1.73 m² and very high proteinuria were significantly associated with the prevalence of CVD.