Poor Bone Mineral Density Is Associated With Increased Risk of Urological Bone Metastases

Objective: To investigate whether a diagnosis of precancer poor bone mineral density (PBMD) is associated with higher risk of urological cancer bone metastasis. Methods: The PearlDiver Database was utilized to conduct a retrospective, propensity-matched cohort analysis of adult patients diagnosed with kidney, bladder, prostate, and testicular cancer with and without a prior diagnosis of PBMD, defined as osteopenia or osteoporosis. Unadjusted and adjusted odds ratios (OR) and 95% confidence intervals are used to compare the rate of newly diagnosed bone metastases between 6 months and 3 years of the initial cancer diagnosis between the experimental and control cohorts. Results: Among 685,066 patients with urological cancers, precancer PBMD was associated with increased odds of bone metastasis at various time periods (1 week, 6 months, 1, 2, and 3 years). The strongest association was appreciated within 1 week of cancer diagnosis (kidney: adjusted odds ratio [aOR], 2.37, P <.001; bladder: [aOR], 2.37, P <.001; prostate: [aOR], 2.84, P <.001; testicular: [aOR], 4.45, P <.001). Bisphosphonates were associated with reduced risk of kidney ([aOR], 0.46, P <.001), bladder ([aOR], 0.61, P <.001), and prostate ([aOR], 0.66, P <.001) cancer bone metastasis. Conclusion: Our findings suggest urology patients with PBMD may be predisposed to forming bone metastases as well as presenting with metastatic disease at time of cancer diagnosis. As such, further studies are needed to elucidate whether PBMD plays a role in bone tropism and whether bone health pertains to prolonging bone-free metastasis.