Combination therapy of anabolic agents and bisphosphonates on bone mineral density in patients with osteoporosis: a meta-analysis of randomised controlled trials

Objective We aimed to determine whether the concomitant combination therapy of anabolic agents and bisphosphonates produces more effects on bone mineral density (BMD) than anabolic agents alone in patients with osteoporosis. Methods We searched MEDLINE, EMBASE and the Cochrane Library for publications from 1 January 1980 to 1 August 2016 to identify all the randomised controlled trials (RCTs) and quasi-RCTs. The primary outcome was the mean per cent changes in BMD at the lumbar spine, the total hip and the femoral neck with an optimal period of treatment (6 to 12 months). The secondary outcome was the mean per cent changes in BMD at the same sites with the full period of recommendation (18 to 24 months). A random-effects model was used to estimate the standardised mean differences (SMDs) and the 95% Cls. Results Seven studies, with 747 patients, were included. With the optimal period, the concomitant combination therapy demonstrated a significant advantage over a monotherapy in BMD improvement at the total hip (SMD 0.42; 95% CI 0.26 to 0.58) and the femoral neck (SMD 0.30; 95% CI 0.14 to 0.46), but not for the spine BMD (SMD 0.13; 95% CI -0.17 to 0.43). With the full period, the concomitant combination therapy did not improve the BMD at the lumbar spine (SMD -0.06; 95% CI -0.71 to 0.59), the total hip (SMD 0.05; 95% CI -0.71 to 0.82) and the femoral neck (SMD -0.32; 95% CI -1.15 to 0.50). Conclusions Compared with anabolic monotherapy, the concomitant combination therapy of anabolic agents and bisphosphonates significantly improved the BMD at the total hip and femoral neck with a shorter term (6 to 12 months) and produced similar benefits on BMD for the longer term (18 to 24 months). Also, the effect of concomitant combination therapy might be affected by the dose of anabolic agents.