No effect of surgery on kidney and cardiovascular risk factors in mild primary hyperparathyroidism: secondary analyses from a 10-year randomized controlled trial.

Objective: Renal function and the skeleton are classic target organs in primary hyperparathyroidism (PHPT), affected by the chronic course of the disease. Most patients diagnosed today exhibit mild PHPT, characterized by slight hypercalcemia and no or unspecific symptoms. Concerns have been raised that PHPT could promote deteriorating kidney function and increase cardiovascular risk directly. To examine the effect of parathyroidectomy (PTX) on mild PHPT on renal function and markers for bone turnover, cardiovascular disease (CVD), and vascular inflammation.

Design: Prospective randomized controlled trial. ClinicalTrials.gov: NCT00522028.

Setting: Eight Scandinavian referral centers.

Participants: From 1998 to 2005, 191 patients with mild PHPT were included in Sweden, Norway, and Denmark. Of these 150 were included in the present analyses.

Intervention: Seventy patients were randomized to PTX and 80 to observation without intervention (OBS).

Measures: e-GFR was calculated based on creatinine and cystatin C. Markers of CVD and systemic inflammation: osteoprotegerin, vascular cell adhesion molecule 1, soluble CD40 ligand, interleukin-1 receptor antagonist, von Willebrand factor. Bone turnover markers: C-terminal telopeptide of type 1 collagen (CTX-1) and serum Procollagen type 1 N-terminal propeptide.

Results: No differences in the development of renal function or vascular and systemic inflammation were detected. CTX-1 was lower in PTX after 10 years.

Limitations: Secondary analyses of a randomized controlled trial.

Conclusion: PTX does not appear to affect renal function or markers of CVD and vascular inflammation in mild PHPT in a ten-year perspective.