Analysis of the kinetics of the parathyroid hormone, and of associated patient outcomes, in a cohort of haemodialysis patients

Abstract

BackgroundObservational studies have recently associated a decrease in serum parathyroid hormone (PTH) level with a higher rate of mortality among hemodialysis (HD) patients. Decreases in PTH level can result from medical intervention (MPD) and surgical parathyroidectomy (PTX), or may occur spontaneously, usually associated with an underlying malnutrition-inflammation syndrome (SPD). The aim of our study was to prospectively identify the incidence of decreases in PTH level in a cohort of HD patients and the frequency distribution of the different causes (MPD, PTX and SPD), as well as to evaluate the survival outcomes for each PTH group (MPD, PTX and SPD) compared to patients who did not experience a PTH decrease over the first 36 months of the study (NPD).MethodsThe 197 patients receiving HD at our center in January 2010, and meeting our eligibility criteria, were enrolled in our prospective study, and were observed for a period of 60 months. A decrease in PTH level >50 % between two successive PTH measurements obtained within an interval <3 months was defined as a significant event. MPD referred to a decrease in PTH due to an increased oral calcium intake, increased dialysate calcium concentration (DCC), increased alfacalcidol use, or use of cinacalcet therapy. A surgical 7/8 PTX was performed in young patients or in patients in whom cinacalcet therapy failed. SPD referred to a decrease in PTH related to a medical or surgical event. Baseline characteristics among patients in each group (MPD, PTX, SPD, and NPD) were evaluated using Fisher’s exact test. The 60-month survival was evaluated using Kaplan-Meier and Cox multivariable proportional hazards models. Univariate and multivariate Cox analyzes were used identify variables with mortality. The relative risk of mortality was expressed as a hazard ratio (HR).ResultsThe distribution of the 197 patients forming our four study groups was 34 % in the NPD group, 35 % in the SPD group, 25 % in the MSD group and 6 % in the PTX group. Among patients in the SPD group, the main acute comorbid conditions were peripheral vascular and cardiac complications, sepsis, fractures, and cancers with an increase in serum CRP level (from 14.3 ± 18 to 132 ± 90 mg/L) and a decrease in serum albumin (from 33 ± 4.5 to 28.6 ± 4 g/L). In the MPD group, the main therapeutic change was an increase in DCC, either independently or in association with cinacalcet therapy. The median survival rate among patients was 10 months for SPD, compared to 22 months among patients in the MPD group (p < 0.001). Using multivariable Cox model and taking the NPD group as reference, the risk of mortality was lower among patients in the MPD group (HR, 0.42[0.2-0.87] p = 0.01), with survival being comparable for the SPD and NPD groups (HR, 1.3 [0.75-2.2]). No mortality was observed in the PTX group.ConclusionThe poor outcomes associated with SPD, related to acute comorbid conditions, should not lead to undertreat secondary hyperparathyroidism whose appropriate medical or surgical therapies are associated with bette...

Parathyroidectomy—A last resort for hyperparathyroidism in dialysis patients

“…They concluded that PTX was associated with improved survival (HR=0.80). These results are consistent with other studies which are also based on large national registry with a long follow‐up . In an editorial, however, Messa questioned the better outcomes of PTX cohorts because of a major problem with the studies—defining the indications for the intervention and in selecting the surgical candidates .…”

Serum Calcium and Phosphorus Levels in Hemodialysis Patients: A Large Population-Based Multicenter Study

“…The inflammatory-malnutrition syndrome was associated with low iPTH and adverse prognosis (37). Given the relationship between inflammatory and nutritional factors and low iPTH levels in our study that has been suggested by other studies, as well (38,39), it is necessary to pay special attention to the nutritional status and inflammatory fac-tors to treat PTH disorders (40). Unfortunately, nutrition screening is not performed routinely in CKD patients in a large number of kidney care centers (41).…”

Severe secondary hyperparathyroidism in patients on haemodialysis is associated with a high initial serum parathyroid hormone and beta-CrossLaps level: Results from an incident cohort

“…The progressive increase of the serum PTH level from month 3 to month 36 is less expected, since individualisation of DCC, alfacalcidol and calcium salts has been applied using the same strategy and is aimed at maintaining a serum PTH level between 150 and 400 pg/mL. Three factors may be involved: a) patients with a low baseline PTH level or having a spontaneous PTH decrease are more likely to die, as we reported recently in the same cohort [ 13 ], and we could have selected patients who were exposed to SHPT; b) SHPT began a long time before dialysis and the increasing slope reflects the spontaneous evolution from CKD stage 3 to stage 5 when prevention remains suboptimal; -c) in patients on HD, our therapeutic strategy is insufficient for preventing the increase of serum PTH due to inadequate biological targets or treatment dosage, especially in patients with higher baseline PTH and CTX levels.…”