Efficacy of Zoledronic Acid in Patients with Systemic Osteoporosis and Problem of «Non Respondents» to the Treatment

Abstract

Prospective study of zolendronic acid efficacy was performed in 112 patients with systemic osteoporosis. Study results confirmed the presence of patients who did not response to the treatment: in 15.7 % of observations reduction of mineral bone density (BMD) continued to progress. No significant differences in initial deviations of resorption and bone formation markers, peculiarities of calcium homeostasis were detected in “non respondents”. At the same time by the 12th month after treatment initiation the relationship between BMD increase with preservation of marked decrease of resorption marker (deoxypyridinoline) and bone formation marker (osteocalcin) was noted, that pointed out the expediency of prognostic model creation. Evaluation of the influence of certain risk factors (age, results of blood and urine biochemical tests, data of densitometry including the results of femoral neck BMD in some patients) using discriminant analysis showed that 81.5% of patients were correctly referred to the groups of patients who responded and not responded to treatment. Out of all initially studied parameters the most significant were 7 that in 78.6% of cases (method sensitivity) enabled to identify the patients with negative treatment effect and in 82.1% of cases (method specificity) - with positive treatment effect.