Nephrolithiasis: A Red Flag for Cardiovascular Risk

Arterial stiffness and cardiovascular risk in patients with nephrolithiasis: a 10-year prospective study

BACKGROUND

Nephrolithiasis is frequently associated with cardiovascular diseases. These conditions present common risk factors: systemic inflammation that promotes oxidative stress leading to arterial wall stiffening may also play a role in plaque formation predisposing to nephrolithiasis.

OBJECTIVES

The aim of this study was to evaluate arterial stiffness indices at baseline and after a 10-year follow-up, in patients with nephrolithiasis compared with patients without.

METHODS

A total of 82 patients (37 men; mean age 45 ± 13 years) were enrolled at the Geriatrics and Nephrology Outpatient Clinic: 66 were diagnosed with nephrolithiasis, whereas the control group consisted of 16 individuals. At baseline and after 10 years, they underwent clinical evaluation and arterial stiffness measurement, such as carotid-femoral pulse wave velocity (CF-PWV), by arterial applanation tonometry.

RESULTS

At baseline, when compared with the control group, patients with nephrolithiasis showed higher SBP and CF-PWV. After 10 years, patients with nephrolithiasis, but not those without, showed a significant raise in CF-PWV, even after adjustment for age and sex. In a stepwise regression model, with CF-PWV changes during the follow-up as the dependent variable, and age, sex, follow-up years, Δ mean arterial pressure, BMI, hypertension and nephrolithiasis as independent variables, nephrolithiasis was proved to be the only significant predictor of ΔCF-PWV, accounting for 6% of the variance.

CONCLUSION

Our study shows higher baseline CF-PWV and greater increase in ΔCF-PWV within 10 years in individuals with nephrolithiasis than in those without, demonstrating an increased cardiovascular risk for nephrolithiasis patients.

Vitamin D and Calcium Supplementation and Urolithiasis: A Controversial and Multifaceted Relationship

Patients with urolithiasis, and particularly those with hypercalciuria, frequently have a marked reduction of bone mineral content up to the levels of osteoporosis, with a significant increase in bone fracture risk. For these reasons, the indication to prescribe vitamin D and/or calcium supplementations is very frequent in such patients. On the other hand, both calcium supplementation, and even more vitamin D therapy, can worsen the risk of developing urolithiasis by increasing calcium, phosphate, and oxalate urinary excretion. Despite the clinical and practical relevance of this issue, the evidence on this topic is scarce and contradictory. Therefore, some concerns exist about how and whether to prescribe such supplements to a patient with a history of kidney stones. In this narrative review, we resume some pivotal pathophysiological concepts strictly related to the dealt topic, and we draw some considerations and personal opinions on the pros and cons of such prescriptions. Finally, we share with the reader our pragmatic algorithm for handling the urolithiasis risk in patients who have strong indications to be prescribed vitamin D and calcium supplementations.

Unravelling the Complex Relationship between Diet and Nephrolithiasis: The Role of Nutrigenomics and Nutrigenetics

Nephrolithiasis is an increasingly prevalent condition, especially in high income countries, and is associated with high morbidity. Extraordinary progress in genetics made the identification of genetic forms of nephrolithiasis possible. These genetic diseases are usually rare and do not account for the most common forms of nephrolithiasis that are the result of several factors such as environment, dietary habits, and predisposing genes. This knowledge has shaped what we classify as nephrolithiasis, a condition that is now recognized as systemic. How and to what extent all these factors interact with one another and end in kidney stone formation, growth, and recurrence is not completely understood. Two new research fields have recently been trying to give some answers: nutrigenomics and nutrigenetics. These fields have the aim of understanding the intricate diet/genome interface that influences gene expression regulation mainly through epigenetic mechanisms and results in specific medical conditions such as cancer, metabolic syndrome, and cardiovascular diseases. Epigenetics seems to play a crucial role and could represent the link between environmental factors, that we are constantly exposed to, and risk factors for nephrolithiasis. In this systematic review, we summarize all the available evidence of proven or hypothesized epigenetic mechanisms related to nephrolithiasis.