Late referral to a nephrologist increases the risk of uremia-related cardiac hypertrophy in patients on hemodialysis

Abstract

Background: The prognosis and outcome of patients with end-stage renal disease are related to the quality of predialysis care and the timing of referral. Late referral (LR) has been correlated with more frequent hospital admissions, malnutrition and cardiovascular mortality after hemodilaysis (HD) is started.

Methods: We investigated the effects of LR on cardiac hypertrophy, uremia-related metabolic risk factors and mortality in patients on HD. A baseline echocardiography was performed in 119 patients on HD, 67 of whom were early referrals (ER, referred more than 3 months before the start of HD) and 52 were LR (referred less than 3 months before the start of HD; median (range): 22.5 (4-120) vs. 1.0 (0-3) months, respectively).

Results: The survival curves showed a higher mortality rate in the LR patients than in the ER patients (log rank, p = 0.004). More patients in the LR group died of cardiovascular disease compared to the ER patients (p = 0.04). The plasma levels of albumin were significantly lower (p < 0.05), and the intact parathyroid hormone (iPTH) and log C-reactive protein (log CRP) were significantly higher in the LR patients compared to the ER patients (p < 0.05 and p < 0.001, respectively). The LR patients, especially nonsurvivors, showed greater impairment of systolic cardiac function and more concentric left ventricular hypertrophy (LVH) than ER patients, as determined by interventricular septal thickness (p < 0.001), left ventricular posterior wall thickness (p < 0.001), relative wall thickness (p = 0.02), and the left ventricular mass index (LVMi, p < 0.001). Interestingly, the duration of the pre-HD treatment, after referral, was positively associated with the plasma albumin (r = 0.229; p = 0.01) and negatively associated with the log CRP (r = -0.350; p < 0.001), iPTH (r = -0.309; p = 0.001) and LVMi (r = -0.268; p = 0.004). Multiple linear regression analysis also demonstrated that the log CRP and iPTH as well as the LR were independently associated with LVMi in the HD patients (p < 0.05).

Conclusions: The results of this study demonstrated that the LR HD patients were at an increased risk for more cardiovascular related mortality, severe concentric LVH and systolic dysfunction accompanied by inflammatory and malnutrition indices, as well as with increased iPTH levels. In the LR patients, the more severe LVH associated with severe inflammatory indices, as well as the higher iPTH levels, may be one of the causes of LR-related mortality.