Is lower income associated with an increased likelihood of qualification for treatment for osteoporosis in Canadian women?

Abstract

We examined whether low income was associated with an increased likelihood of treatment qualification for osteoporotic fracture probability determined by Canada FRAX in women aged ≥50 years. A significant negative linear association was observed between income and treatment qualification when FRAX included bone mineral density (BMD), which may have implications for clinical practice.

Introduction: Lower income has been associated with increased fracture risk. We examined whether lower income in women was associated with an increased likelihood of treatment qualification determined by Canada FRAX®.

Methods: We calculated 10-year FRAX probabilities in 51,327 Canadian women aged ≥50 years undergoing baseline BMD measured by dual energy x-ray absorptiometry 1996-2001. FRAX probabilities for hip fracture ≥3% or major osteoporotic fracture (MOF) ≥20 % were used to define treatment qualification. Mean household income from Canada Census 2006 public use files was used to categorize the population into quintiles. Logistic regression analyses were used to model the association between income and treatment qualification.

Results: Percentages of women who qualified for treatment based upon high hip fracture probability increased linearly with declining income quintile (all p trend <0.001), but this was partially explained by older age among lower income quintiles (p trend <0.001). Compared to the highest income quintile, women in the lowest income quintile had a greater likelihood of treatment qualification based upon high hip fracture probability determined with BMD (age-adjusted odds ratio [OR], 1.34; 95% confidence intervals (CI), 1.23-1.47) or high MOF fracture probability determined with BMD (age-adjusted OR, 1.31; 95% CI, 1.18-1.46). Differences were nonsignificant when FRAX was determined without BMD, implying that BMD differences may be the primary explanatory factor.

Conclusions: FRAX determined with BMD identifies a larger proportion of lower income women as qualifying for treatment than higher income women.