Incongruent Treatment Recommendations Between Left and Right Hip Bone Mineral Densities

Objective The official position of the International Society for Clinical Densitometry (ISCD) is that either hip site can be scanned with dual-energy X-ray absorptiometry (DXA) imaging. Whether there is a difference in guideline-based treatment recommendations between hip sites has not previously been assessed. Methods We conducted a retrospective analysis of all individuals who underwent DXA imaging at a single center from September 1, 2018, to October 31, 2019. Women aged ≥ 40 years old and men aged ≥ 50 years old were included. Individuals without bilateral hip measurements or who were on osteoporosis treatment were excluded. The 10-year probability of fracture using the fracture risk assessment tool (FRAX) was calculated for each hip when the worst T-score was in the osteopenia range. Results Of the included participants, 10% (n = 151/1505) had incongruent treatment recommendations (ITR) between the left and right hips. In the ITR group, 70% (n = 106) had osteopenia and 30% (n = 45) had osteoporosis. Age was the only significant risk factor for ITR overall (OR: 1.06, 95% CI: 1.04-1.09). In the osteopenia group, however, age (OR: 1.17, 95% CI: 1.13-1.21), history of parental hip fracture (OR: 3.16, 95% CI: 1.65-6.05), and glucocorticoid use (OR: 4.18, 95% CI: 1.6-11.0) were associated with ITR. In the osteoporosis group, the right hip (femoral neck and total) T-scores were significantly lower compared to the left. Conclusion Measuring bone mineral density on both hips changes treatment recommendations in 10% of people. This was more likely in those with osteopenia who were older, had a parental history of hip fracture, or were on glucocorticoids. Measuring both hips did not add time or cost to patient care. Given the minimal disadvantages to measuring both hips, there should be a strong consideration to change the current guidance of only measuring one hip.