Age-related bone mineral density patterns in a large German clinical DXA cohort: device-specific comparisons with international reference populations.

UNLABELLED: In a large German clinical DXA cohort, comparisons with international reference populations were strongly device-dependent. iDXA values were consistently lower, whereas Prodigy Pro values showed closer but age- and cohort-dependent agreement. The data should not be interpreted as scanner-independent German normative reference values.

PURPOSE: To describe age-related bone mineral density patterns in a German DXA cohort and to compare device-specific femoral neck (FN) and total hip (TH) standardized BMD values with international reference cohorts.

METHODS

We retrospectively analyzed data from 6,086 women using GE Lunar iDXA or Prodigy Pro systems. Device-related differences were evaluated separately by age-group and measurement site using absolute and percentage differences, Hedges' g, Welch tests, and multiple comparison adjustment. For external comparisons, FN and TH BMD data for women aged 20-79 years were converted to standardized BMD and compared separately by device with NHANES III, the Irish DXA-HIP study, and the Italian DINS study. Hedges' g with 95% confidence intervals, two-sided Welch tests, and Holm-adjusted p values were calculated from summary statistics.

RESULTS

Prodigy Pro BMD values were higher than iDXA across most age groups and measurement sites, with moderate effect sizes in younger and middle-aged women and smaller differences at older ages. In external comparisons, iDXA sBMD was lower than all reference cohorts in all 36 comparisons (age/site/reference), remaining significant after Holm adjustment. Prodigy Pro showed smaller and age-dependent differences, with 18 of 36 comparisons remaining Holm-significant. Across the reference cohorts, Prodigy Pro percentage differences ranged from -8.9% to 1.3%, whereas iDXA ranged from -19.0% to -1.8%.

CONCLUSION

Comparisons with international reference cohorts were strongly dependent on the DXA device. The present clinical cohort should not be interpreted as a scanner-independent German normative reference population. Device-stratified results provide a more appropriate description of concordance with international datasets than pooled analyses.