Background: In osteoporosis, the use of bone turnover markers(BTMs) is recommended 3 months after start of bisphosphonate treatment, but data are scarce, outside the context of clinical trials, on the value of the long-term use of these markers to monitor efficacy of treatment. Our objective was to assess the value of BTMs in the management of osteoporosis beyond 3 months of starting treatment with bisphosphonates.
Methods: Consecutive patients attending the outpatient clinic, aged ≥18years, who started bisphosphonate treatment between 2006-2012 with available baseline and sequential BTMs and BMD data were included. Subgroup analysis was performed when a fracture ≤12months before start of treatment.
Results: 134 patients (98 female), mean age 64.6 years(range 22-89) were included. Sixty-eight (51%) sustained a fracture ≤12 months before start of therapy with median time of 4.5 months. Baseline P1NP and CTX were 57.6±27.6ng/ml and 0.39±0.23ng/ml in the whole group, and 60.4±28.5ng/ml and 0.43±0.25ng/ml in patients with recent fractures. P1NP decreased by 66% (p<0.001) within 12 months, irrespective of a recent fracture. There was a significant correlation between decrease in P1NP at 12 months and increases in lumbar spine(LS) BMD at 12 months(5%,p=0.015) and 24 months(7%,p=0.003), which persisted after adjustment for age, gender, BMI, glucocorticoids, smoking, alcohol use and 25-OH vitamin D levels. In patients with a recent fracture, changes in P1NP at 12 months also significantly correlated with changes in LS BMD at 12 and 24 months (r=-0.309,p=0.046 and r=-0.372,p=0.040).
Conclusion: The significant relationship between changes in BTMs at 12 months and changes in LS BMD at 12 and 24 months after start treatment with bisphosphonates, also observed after a recent fracture, justifies and supports the long-term use of these markers in the management of osteoporosis in the clinic after start of bisphosphonate therapy.
Disclosure: The authors declared no competing interests.