Treat to target is the use of a physiologic marker as a monitor of effectiveness or compliance to an intervention. A recent example has been the progressive use of CTX-1 (Marker of osteoclastic activity) as a surrogate of bone resorptive activity in osteoporosis treatment. CTX-1 levels were demonstrated to be inversely related to drug efficacy in the suppression of bone resorption. As far as fragility fractures are concerned, no reference value of CTX-1 for any index fracture sites was found in the literature. In order to prevent subsequent fractures, efforts to better manage this chronic disease are to be explored. The main objective of this study was to compare and validate the use of serum CTX-1 to the perceived compliance to treatment.

Five hundred and forty three patients (men and women) 40 years of age or older who had been treated for a fragility fracture were enrolled. The purpose of this study was to correlate the measurement of CTX-1 with the perceived compliance to treatment of patients at the time of fracture and at six, 12 and 18 months after initiation of treatment. Our secondary objectives were to evaluate two different CTX-1 suppression target levels (CTX-1< 0.3 ng/mL and CTX-1<0.2 ng/mL), to determine CTX-1 values according to fracture sites, and to explore the profile of patients with subsequent fractures.

Considering index fractures, compliant patients under treatment at baseline had lower CTX-1 levels than non-compliant patients (p=0.052). Patients who were compliant to treatment at six, 12 and 18 months also had lower CTX-1 levels than non-compliant patients (p=0.000). When index fractures were divided into fracture sites, regardless of CTX-1 suppression target level (i.e. CTX-1< 0.3 or 0.2 ng/mL), significant CTX-1 suppression was observed in non-hip and non-vertebral (NHNV) fractures at six, 12 and 18 months (p0.05). No clinically relevant difference was observed between the profile of patients with and without subsequent fractures.

The correlation between serum CTX-1 at the time of fracture and at six, 12, 18 months and the perceived compliance to treatment was validated for NHNV fractures supporting the concept of the available treatments and their effects on bone remodeling for this type of fracture. The correlation was not validated for hip neither for vertebral fracture. There was no correlation between CTX-1 levels and subsequent fracture risk.

Purpose

In 2010, the new clinical guideline of Osteoporosis Canada for the diagnosis of osteoporosis, clearly indicates that patients with high-risk of fracture are those that have already sustained a fracture (osteoporotic fracture). Until now, only 12% of the 3,400 fractures that we treat each year receive a treatment for osteoporosis. We are validating an evaluation protocol and a multidisciplinary systematic follow-up approach for osteoporosis. Patients are managed by a clinical nurse specialist. We are recruiting 543 patients with an osteoporotic fracture at Hal du Sacré-Coeur de Montréal. We aim to evaluate: 1) the incidence of a second osteoporotic fracture, 2) the initiation of a treatment and determine the compliance and adherence to treatment and 3) the evaluation of CTX-1 and Osteocalcin at Baseline, 6, 12,18 et 24 months (treatment efficacy) and 4) the functional outcome and quality of life post-fracture.