Adipokines in Peritoneal Dialysis: Relevant Clinical Impact According to Body Composition

Abstract

Adipokines impact on clinical outcomes is not adequately addressed in peritoneal dialysis (PD). We investigated the impact of leptin/adiponectin ratio (L/A) as a predictor of cardiovascular events (CVE) in PD, taking into consideration patient's body composition and the potential role of glucose load. We prospectively followed 66 prevalent PD patients for 47.0 ± 28.2 months. New CVE were evaluated. Lean tissue index (LTI), relative fat mass (relFM) and relative overhydration (relOH) using multifrequency bioimpedance (BCM) were assessed; serum lipids, interleukin-6 (IL-6), leptin and adiponectin were measured. We established the determinants of L/A using multiple linear regression and the impact of L/A on CVE. Obesity was present in 47 (73.4%) patients according to relFM, and in seven (10.6%) according to body mass index (BMI). Leptin and L/A exhibited a stronger correlation with relFM (both r = 0.62, P < 0.0001) than with BMI (r = 0.46 and r = 0.51, respectively, both P < 0.0001). L/A showed a significant correlation with triglycerides (r = 0.41, P = 0.001) and HDL-cholesterol (r = -0.358, P = 0.003), better than isolated leptin or adiponectin. RelFM (RR = 0.130, 95%confidence interval [CI]:0.086-0.174, P < 0.0001) and LTI (RR = 0.194, 95%CI:0.037-0.351, P = 0.016) were independent predictors of L/A (R(2) = 0.67). Patients who suffered new CVE were older (59.12 ± 12.41 vs. 47.52 ± 13.84years, P = 0.003) and had a higher relOH (11.28 ± 7.29 vs. 6.60 ± 8.16%, P = 0.028). L/A was significantly higher in patients with CVE[2.29 (1.79) vs. 0.65 (1.73), P = 0.028] but this association was only put on evidence after excluding patients with wasting. BMI is an inaccurate method to classify obesity in PD since it underestimates its prevalence compared with body composition assessment using BCM. High adiponectin and low leptin are associated with a more favorable metabolic risk profile in peritoneal dialysis. The L/A is determined by relFM and by LTI. A higher L/A is associated with CVE in PD patients without wasting.

Insulin Resistance in Nondiabetic Peritoneal Dialysis Patients

“…In our study, peritoneal glucose absorption was not correlated with any insulin resistance indices, nor with fat mass, and did not differ in insulin-resistant patients versus the lower HOMA-IR group. Our results also reproduce our previous observation that BMI underestimates obesity prevalence in PD (6), and that obesity increases in patients on PD for .1 year (61%). This supports other studies reporting increased fat mass with time on PD (8,(26)(27)(28).…”

“…We have previously reported that rel.FM and LTI predicted LAR independently of peritoneal glucose absorption (6). The results of the present study corroborate this, underlining that insulin resistance is aggravated in both extremes of the nutritional spectrum: obese patients exhibited higher LAR values, strongly positively correlated with HOMA-IR, but the two patients with protein-energy wasting also evidenced insulin resistance while LAR was ,1.…”

“…In a previous study of PD patients followed up on for 47 months, no difference was found concerning small-solute transport rate between patients with and without cardiovascular events (6). In the present study, we also did not find any significant difference concerning LAR, IGFPB-1, glucose absorption, or body composition parameters between fast transporters and other categories of small-solute transport.…”

“…However, it is feared that with time the cumulative exposure to glucose solutions used in PD might lead to systemic hyperglycemia, obesity, and aggravate insulin resistance, which could contribute to increased cardiovascular risk (4). The incidence of overweight and obese patients is widely prevalent in contemporary PD populations (5,6), although there is much controversy about the major role of peritoneal glucose absorption on body fat accumulation over time (7,8). A single study has evidenced that insulin resistance evaluated by homeostasis model assessment (HOMA-IR) is a predictor of cardiovascular disease in PD patients (9); however, the specific role of peritoneal glucose absorption, small-solute transport, or obesity were not addressed.…”

“…LAR has been recently proposed as a new atherogenic index, since it has been associated with cardiovascular events in PD (6). However, no study has explored the association between these newly adipokine-based insulin resistance indices and the HOMA-IR in PD patients.…”