Association between serum phosphate and calcium, long-term blood pressure, and mortality in treated hypertensive adults

Objectives: Abnormalities of bone mineral parameters are associated with cardiovascular morbidity and mortality in patients with chronic kidney disease and the general population. Methods: We assessed the impact of baseline serum phosphate and calcium on longitudinal blood pressure (BP) control and survival in hypertensive adults. We studied 9260 hypertensive adults followed for 40 years (151 789 person-years). Changes in BP over initial 5-year follow-up were analysed using generalized estimating equations. Survival analyses were performed using Cox proportional hazards model. Results: Serum phosphate levels were higher in hypertensive women (1.10 mmol/l ± 0.20) than compared to men (1.02 mmol/l ± 0.21). In treated hypertensive patients, higher baseline serum phosphate was significantly associated with poor longitudinal SBP reduction (one standard deviation increase in phosphate was associated with 0.22 and 0.59 mmHg higher SBP at 5 years in men and women, respectively). Higher serum phosphate was significantly associated with all-cause and cardiovascular mortality in men, whereas in men and women, serum calcium significantly predicted all-cause and noncardiovascular mortality. In hypertensive patients with chronic kidney disease, higher phosphate was significantly associated with poorer survival. Conclusion: In hypertensive patients, serum phosphate and calcium are significantly associated with reduced all-cause and cardiovascular survival and this appears not to be related to BP control