Emerging data on cardiovascular risk in primary hyperparathyroidism.

Abstract

The cardiovascular risk profile of patients affected by primary hyperparathyroidism (PHPT) has been an issue of debate over the last years. Studies regarding the potential damages caused by increased serum levels of parathyroid hormone (PTH) and/or calcium, have yielded controversial results, suggesting either the presence or the absence of damage [1, 2]. It is interesting to note that the answer to this question is further complicated by the changing clinical presentation of PHPT over the last decade. Indeed, once considered a symptomatic disorder characterized by significant hypercalcemia with kidney stones and/or bone involvement [3– 5], today PHPT is most commonly seen in asymptomatic individuals with milder hypercalcemia, due to the large availability of routine serum calcium measurements and developments in assay systems. A new presentation is now emerging, characterized by normocalcemia and elevated serum parathyroid hormone levels (the so-called ‘‘normocalcemic primary hyperparathyroidism’’). Recently in this Journal, Procopio et al. reported an increased prevalence of intermediate-high cardiovascular risk score (CRS), both in symptomatic and asymptomatic PHPT patients, as compared to healthy controls [6]. Their data are in line with several previous studies that reported an increased coronary artery and cerebrovascular morbidity in PHPT [7, 8]. By means of a multivariate analysis, they also showed that, PHPT status predicts the presence of intermediate-high CRS and metabolic syndrome [9], while elevated calcium levels predict altered glucose tolerance among the components of metabolic syndrome. Procopio et al. added new information on an emerging aspect of patients with this glandular disorder; however, there are also some limitations that should be kept in mind when interpreting the results obtained. For example, the classification of patients is somewhat arbitrary. Asymptomatic patients with complications should no longer be considered as such; indeed, future classifications should be based on the presence or absence of complications. Just to make an example, patients may be asymptomatic, but can be incidentally discovered to have a kidney stone by ultrasound; in such a case she/he is asymptomatic but already has a complication of the disease. In essence, the term asymptomatic does not mean without complications; in this context, also a vertebral fracture may be asymptomatic but represents a complication. Secondly, the paper does not include any follow-up after surgery; this could have added meaningful information about the possible reversible effects of a restored biochemical calcium metabolism on cardiovascular risk factors. The current data conflict on this last issue [10, 11], possibly due to the different timing of surgery. For example in the case of hypertensive patients, it is entirely possible that parathyroidectomy would be effective only if performed in an early phase of the disease, when structural abnormalities are not present. A similar situation can be observed in other endocrine disorders determining arterial hypertension, such as primary hyperaldosteronism [12]. It has been shown that, in the general population, cardiovascular risk factors can result in cardiac organ damage which might be detected by echocardiographic measurements. Conflicting results are present in the current literature in relation to the finding of left ventricular (LV) hypertrophy and LV systolic and diastolic dysfunction in J. Pepe S. Piemonte C. Cipriani M. Cilli S. Minisola (&) Department of Internal Medicine and Medical Disciplines, Sapienza University, Viale del Policlinico 155, 00161 Rome, Italy e-mail: salvatore.minisola@uniroma1.it