The use of serial bone mineral density (BMD) monitoring while on osteoporosis treatment is debatable. The percentage of women categorized as suboptimal responders to antiresorptive drug treatment was calculated using two criteria of serial BMD change. Cohort research was conducted in a single-payer government health system in Manitoba, Canada, using administrative datasets. Participants were postmenopausal women aged 40 or older who were using antiresorptive medicines and had three consecutive BMD measurements. Women who were discontinuing or switching treatments were not included. The proportion of women whose spine or hip BMD declined substantially during the first or second interval of BMD monitoring was calculated. BMD decreases at both monitoring intervals were classified as suboptimal responder status, as was BMD reduction from baseline to final BMD. The analytic cohort included 1369 women. BMD monitoring intervals were 3.0 and 3.2 years on average. In the first period, 3.2 percent and 6.5 percent of women had a drop in spine or hip BMD; in the second interval, 8.0 percent and 16.9 percent had decreased; however, only 1.4 percent had recurrent losses in both intervals. Only 3.2 percent and 7.4 percent of patients demonstrated BMD decrease at the spine or hip during the whole therapy period, respectively. The findings may not be applicable in cases of poor adherence to antiresorptive medicine or anabolic treatment usage.

A very tiny percentage of women who were extremely adherent to antiresorptive treatment for osteoporosis maintained BMD reductions on repeated assessments. Multiple serial BMD monitoring should be questioned in order to discover chronic poor responders.