Endocrine Abstracts

Background: Hypogonadism in males is associated with a reduction in bone mineral density (BMD). It is known that the reversal of this is achievable through adequate hormone replacement; however, the degree to which this is dependent on the proportion of time patients spend within the recommended therapeutic range (>15 nmol/l) in real-ife has not yet been established.

Aim: To evaluate the degree to which the proportion of time that a hypogonadal patient’s testosterone levels are maintained within the target range affects the magnitude of their BMD improvement.

Methods: This retrospective, longitudinal observational, study included 115 patients aged 25–87 ( ± 15.1) treated ata regional tertiary centre between 2006 and 2019. BMD measurements were performed using Bone Densitometry (DXA).The target range of testosterone >15 nmol/l was used as per nationalguidelines. Proportion of time spent within target range (TST)was expressed as a percentage of the treatment duration and grouped into 4 ranges; <25, 25–50, 50–75, >75%. Between-groups differences were analysed using the Kruskal-Wallis test.

Results: Mean percentage of treatment duration spent within target range was 44.2 ± 27.2 with 43 (42%) of patients exhibiting an increase in t-score values for both Femoral Neck (FN) and L2-L4 measurements during their treatment period. The median change in bone mineral density for FN BMD was 0.2 and for L2-L4 it was 0.4. Median improvement in FN BMD for <25% = −0.05; 25–49% = 0; 50–75% = 0.1; >75% = 0.2 showing a linear increase across groups, however differences lacked statistical significance (P = 0.64). For L2-L4 BMD measurements, the median improvement values were <25% = −0.4; 25–49% = 0.5; 50–75% = 0.3; >75% = 0.3. These scores between groups were also not statistically significant (P = 0.92).

Conclusion: The results of this real-life longitudinal, retrospective observational study did not show a significant association between time spent in recommended target range of testosterone and an increase in BMD. Whilst a relationship is evident for the FN scores, the absence of a statistically significant difference potentially implies the influence of multiple confounders in practice. Cofounders, such as low sample numbers, should be explored and other modalities of bone protection should also be considered for BMD improvement in these patients.