Impact of successful secondary hyperparathyroidism treatment on cardiovascular morbidity in patients with chronic kidney disease KDIGO stages G3b-5.

Introduction: Chronic kidney disease is common, with a projected increase to 5.4 million people in need of kidney replacement therapy by 2030. As many as 61.7% of patients on hemodialysis have secondary hyperparathyroidism (SHPT). This has been associated with high cardiovascular morbidity. The present study investigates the effect of SHPT treatment success on cardiovascular morbidity in patients with CKD KDIGO stages G3b, 4, and 5.

Methods: A retrospective single center analysis of 211 chronic kidney disease stages G3b-5 patients undergoing computed tomography for coronary artery calcium (CAC) scoring at the University Hospital of Zurich between 2015 and 2019 was performed. The presence of and control of SHPT was assessed at the timepoint of CAC scoring and 6-12 months prior. Information on left ventricular ejection fraction (LVEF), left ventricular hypertrophy (LVH), and left ventricular myocardial mass index (LVMMI) were calculated from echocardiography values obtained at the timepoint of CAC scoring. Occurrence of major acute cardiovascular events, including acute coronary syndrome (ACS), within 1 year of CAC scoring was drawn from the charts. Independent predictive factors for ACS and LVH were assessed by multivariable analysis.

Results: Thirty-four percent (n=72) of the patients had uncontrolled SHPT, whereas 66% (n=139) had either no (n=18%, n=39) or a controlled SHPT (n=48%, n=100). The CKD stage G3b-5 patients with uncontrolled SHPT had a significantly lower LVEF (p=0.028) and significantly more pronounced LVH (p=0.003) and a higher LVMMI (p=0.002) than the group with either no SHPT or well-controlled SHPT. Uncontrolled SHPT in the observed CKD cohort had a significantly higher risk for developing ACS (p=0.011, HR 2.76, 95%CI 1.26-6.05) compared to no or controlled SHPT patients (41.7% vs 31.7%). While patients with uncontrolled SHPT showed a median CAC score of 290 (IQR 18-866), those with no or controlled SHPT had a lower median CAC score of 194 (IQR 14-869), although not significant (p=0.490). Patients with CAC scores >400 displayed a significantly higher incidence of ACS (56.8% vs 33.1%, p=0.010).

Conclusions: SHPT is common (82%) in advanced CKD (≥G3b) patients and insufficiently controlled in one-third of patients. Insufficient control of SHPT is associated with higher cardiovascular morbidity, lower LVEF, increased LVH, and a higher incidence of ACS. Thus, increased focus on SHPT control in CKD patients may have a beneficial impact on cardiovascular outcomes.