Elsevier

Bone

Volume 51, Issue 3, September 2012, Pages 332-337
Bone

Original Full Length Article
Prevalence and progression of cardiovascular calcifications in peritoneal dialysis patients: A prospective study

https://doi.org/10.1016/j.bone.2012.06.002Get rights and content

Abstract

Background

Patients on dialysis may have abnormal serum levels of Ca, P and parathyroid hormone, with related bone diseases. This population has an increased risk of death, with cardiovascular calcification (CC) a contributing factor. Patients on peritoneal dialysis appear to be at increased risk of hyperlipidemia, a contributing factor to atherosclerotic plaque formation. Although several studies have described the presence and progression of CC in hemodialysis populations, there are fewer data in patients on peritoneal dialysis.

Study design

The Renal Osteodystrophy and Calcifications: Key factors in Peritoneal Dialysis (ROCK-PD) study was a 36-month, prospective observational study conducted in Italy. The study examined the presence and progression of CC in two cardiac valves and five arterial sites. The potential associations of serum Ca and P with mortality and cardiovascular morbidity, demographic, clinical and blood chemistry variables was investigated.

Results

CC was present in 77% of patients at baseline (N = 369) and in 90% of patients by study end (N = 145), progressing in 73% of patients. There were 42 deaths (11%). Analyses showed a marked correlation between baseline P levels and the presence of left ventricular hypertrophy. However, there were no consistent correlations between serum Ca or P with mortality or morbidity.

Conclusions

CC was common in peritoneal dialysis patients and progressed in a majority of patients.

Highlights

► Cardiovascular calcifications are considered an important prognostic factor. ► Few data are available on cardiovascular calcifications in patients on peritoneal dialysis. ► Prevalence of cardiovascular calcifications increased from 77% to 90% in 3 years. ► Cardiovascular calcifications progressed in over 70% of peritoneal dialysis patients. ► Serum calcium and phosphate levels are not predictors of calcification prevalence and progression. ► Serum phosphate levels are positively associated with left ventricular hypertrophy.

Introduction

The signs and symptoms of chronic kidney disease mineral and bone disorder (CKD-MBD) worsen as renal function decreases [1]. Uncontrolled, this can lead to high levels of serum Ca, P and parathyroid hormone (PTH), increasing the risks of renal osteodystrophy, cardiovascular calcification (CC) and morbidity [2], [3], [4], [5]. A dynamic bone disease can result from over-suppression of PTH in this population; the resulting Ca release and hypercalcemia are also linked with CC, increased risk of fractures and mortality [6]. International guidelines for CKD-MBD recommend targets for serum PTH, Ca and P [6]. However, these are difficult to achieve and dialysis patients remain at risk [4], [7].

Patients on dialysis have increased risk of hyperlipidemia and cardiovascular disease (CVD) [4], [8], [9], [10], [11], [12], [13]. Patients on peritoneal dialysis (PD) with CVD or diabetes potentially have a higher overall mortality risk, which may depend in part on CC [14], [15], [16].

Data on CC in patients with CKD-MBD are mostly limited to hemodialysis (HD) or mixed dialysis populations [17], [18]. Studies on progression of CC solely in patients on PD are few, and limited to 1-year follow up [8], [19]. We therefore conducted the 3-year prospective observational Renal Osteodystrophy and Calcifications: Key factors (ROCK)-PD study to characterize the presence and progression of CC in a PD population and investigated the potential associations of CC and serum Ca and P with morbidity.

Section snippets

Study population

This was a multicenter, observational, prospective study conducted in 38 dialysis centers across Italy between 2002 and 2007. The study did not guide treatment nor influence clinical management of patients.

Patients were enrolled if they were ≥ 18 years, receiving PD. Patients were excluded if their life expectancy was < 6 months or they had evident malignancies. Patients were withdrawn in case of renal transplant, switching to HD, if the clinician deemed it appropriate for clinical or

Patient disposition

ROCK-PD ran from 2002 to 2007. Disposition of patients is shown in Fig. 1. There were 224 withdrawals, most frequently switching to HD (42%) and renal transplant (28%).

Demographics, dialysis vintage and concomitant therapies for analysis population

Baseline patient demographics are presented in Table 1.

Median lipid levels were at or slightly above the upper limit of normal.

Usage of active vitamin D (calcitriol) rose from 57% to 61% and usage of statins rose from 30% to 39% by study end. Total phosphate binder usage dropped slightly from 89% to 83%, owing mostly to a drop in

Discussion

CKD-MBD develops as the kidneys lose their ability to maintain Ca and P homeostasis. A major consequence is a 20-fold increased risk of death [22]. Increased age, diabetes, raised levels of serum Ca, P, lipids and PTH are recognized risk factors for CVD for patients on dialysis [2], [7], [23], [24], [25], [26]. The ROCK-PD population exhibited many of these risk factors.

To our knowledge, this is the largest prospective observational study of patients on PD. We used echocardiography to identify

Conflict of interest statements

Dr. Maurizio Gallieni: none

Dr. Flavia Caputo: none

Dr. Armando Filippini: none

Dr. Paolo Gabella: none

Dr. Michele Giannattasio: none

Dr. Antonio Stingone: none

Dr. Marco Farina: none

Acknowledgments

Statistical analysis was provided by BiOikoS FARMA s.r.l., Bologna, Italy and editorial assistance was provided by Brooker Communications, Switzerland. Both were funded by grants from Amgen (Europe) GmbH, Zug, Switzerland.

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    1

    See Appendix 1 for the complete list of investigators.

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