Changes in bone mineral density (BMD): a longitudinal study of osteoporosis patients in the real-world setting

In clinical practice, the frequency of patients achieving improved T-scores and the expected change in bone mineral density (BMD) according to osteoporosis drugs is unknown. We found that osteoporosis medications infrequently achieve improved femoral neck T-scores over 1.2 years. BMD increases were more often seen with IV bisphosphonates and denosumab.

To determine the frequency of osteoporosis patients achieving improvement in T-scores and quantify the change in bone mineral density (BMD) over time according to osteoporosis medication use.

The study included all patients receiving clinical care at United Osteoporosis Centers, Gainesville, GA, 1995-2015, who had at least two measures of femoral neck BMD (N = 1232). We evaluated successive pairs of BMD tests to describe the distribution of transitions between T-score categories. Generalized estimating equations were used to estimate %BMD change between successive pairs of BMD tests according to osteoporosis medication, adjusted for age, sex, height, weight, baseline BMD, previous fracture, and follow-up time.

Mean (±SD) age was 68 (±10) years, and 90% of patients were women. Mean baseline T-score was - 2.04 (± 0.85). In total, 1232 patients had 4918 pairs of successive BMD tests, with a mean 1.2 years (± 0.9) between assessments. Frequency of transition to an improved T-score category was 41% when prior T-score ≤ - 3.5, and 15% when prior T-score - 1.99 to - 1.50. Most individuals (69%) remained in the same T-score category. BMD increased 0.54% (95% CI 0.23-0.85%) with IV bisphosphonates and 1.23% (95% CI 0.56-1.90%) with denosumab, whereas no significant change was seen with oral bisphosphonates, teriparatide, or raloxifene.

Osteoporosis patients are unlikely to improve femoral neck T-scores over 1.2 years. Additional studies are needed to determine the optimal time to repeat BMD testing while receiving osteoporosis treatment and to determine whether fracture risk is reduced in patients who achieve target T-scores.