Changes in biomarkers of bone turnover in an aripiprazole add-on or switching study.

Background: The association between mental illness and osteoporosis and fractures is particularly pronounced in psychotic disorders. Antipsychotic use has previously been described to affect bone density. Method: A 52-week follow-up of patients switched to aripiprazole or with aripiprazole added on, conducting a specific analysis of markers of bone turnover: urinary NTX (a biomarker of bone resorption) and serum BSAP (a biomarker of bone formation). Baseline and serial measurements of bone markers NTX, BSAP and of hormones prolactin, oestrogen and testosterone were done at weeks 0 and 1, 2, 6, 12, 26 and 52, respectively. Results: NTX concentration reduced over time but this did not reach significance in the whole group (log-NTX: beta =-0.0012, p= 0.142). For BSAP the addition of or replacement with aripiprazole produced a significant reduction (log-BSAP: beta=-0.00039, p= 0.002). Analysis with prolactin similarly showed a significant reduction (log-prolactin: beta = -0.0024, p > 0.001); other hormones did not change significantly. Sensitivity analysis to compare the switchers to aripiprazole versus the "add-on" showed that the former group had a significant reduction in NTX. Conclusions: We found that switching to aripiprazole was associated with changes in molecular biomarkers of bone resorption, indicating a more favourable profile for bone health. (c) 2015 Elsevier B.V. All rights reserved.