Effect of Telmisartan and Losartan on Bone Turnover Markers in Patients with Newly Diagnosed Stage I Hypertension

Methodology and Course of the Study

A total of 42 patients with newly diagnosed stage I hypertension (defined according to JNC 7 classification as systolic blood pressure [BP] 140–159 mmHg or diastolic BP 90–99 mmHg) were included in the study. A total of 22 patients (mean age 54.2 years; 50% women) took telmisartan at a dose of 80 mg/day for 12 weeks, while the remaining 20 patients (mean age 49.3 years; 40% women) were assigned to the group taking losartan at a dose of 100 mg/day. The exclusion criteria were as follows:

• use of substances affecting calcium metabolism (i.e., products containing calcium or vitamin D, bisphosphonates, levothyroxine, corticosteroids, antidepressants, fibrates, nonsteroidal anti-inflammatory drugs, selective estrogen receptor modulators, antiepileptics)
• serum creatinine level > 132 µmol/l for men and 124 µmol/l for women;
• malignant neoplastic disease and other conditions affecting calcium or vitamin D metabolism (malabsorption or Cushing's syndrome, kidney or liver disease, primary hyperparathyroidism, sarcoidosis)
• hormonal treatment in the last 3 months
• pregnancy or lactation
• smoking or drug abuse
• premenopausal women

Before starting antihypertensive therapy, blood was drawn from the patients after overnight fasting. Serum levels of calcium, phosphorus, 25-hydroxyvitamin D (25-OHD), bone-type alkaline phosphatase (Bs-ALP), parathyroid hormone (PTH), osteocalcin (OC), interleukin 6 (IL-6), and N-terminal telopeptide (NTx) in 24-hour urine were determined. Laboratory tests were repeated after 12 weeks of taking sartans.  

Results

In both groups of patients, statistically significant increases in serum 25-OHD levels and decreases in parathyroid hormone were observed after 12 weeks. Levels of Bs-ALP, OC, NTx in urine, and IL-6 also decreased. However, serum calcium and phosphorus levels did not differ significantly compared to baseline. In the covariance analyses, after removing the effect of 25-OHD and PTH, no significant changes were observed in any of the monitored bone turnover parameters after 12 weeks of treatment.

Changes in monitored bone metabolism parameters were similar in both groups. However, a significant decrease in mean IL-6 levels was observed only in the group taking losartan. The reduction in 24-hour urinary NTx was statistically significant in both groups.

Baseline blood pressure values did not differ significantly between patients taking telmisartan and losartan. After 12 weeks of use, the mean systolic blood pressure was 126.5 and 124.4 mmHg and diastolic BP was 79.8 and 78.9 mmHg in the telmisartan and losartan groups, respectively.

Discussion and Conclusion

After eliminating the influence of changes in 25-OHD levels, no significant effect of telmisartan or losartan on bone turnover markers was observed after 12 weeks in newly diagnosed patients.

However, the study is limited by the relatively short duration of sartan use, the small size of the study population, and the absence of bone density measurements. Healthy patients were also not included as “controls,” and the study was not randomized. Since the study ran from late winter to late spring, changes in parathyroid hormone and 25-OHD levels could also be related to seasonal fluctuations.

To assess the effects of AT₁ receptor blockers on bone density and fracture risk, especially in postmenopausal women, a randomized controlled clinical study needs to be conducted in the future.

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Source:

Aidoğan I. B., Ererslan E., Ünlütürk U. et al. Effects of telmisartan and losartan treatments on bone turnover markers in patients with newly diagnosed stage I hypertension. J Renin Angiotensin Aldosterone Syst 2019 Jul-Sep; 20 (3): 1–6, doi: 10.1177/1470320319862741.