Dementia diagnosis and osteoporosis treatment propensity: a population-based nested case-control study.

AIM: Increasing age and a diagnosis of dementia both dramatically increase the risk of serious osteoporosis-related sequela. We sought to examine the factors associated with osteoporosis treatment, in relation to dementia diagnosis, in older adults with osteoporosis. METHODS: This was a population-based, retrospective, nested, case-control study utilizing administrative healthcare data from British Columbia, Canada. Community-based individuals aged ≥65 years with an osteoporosis diagnosis and continuous enrolment in the provinces' drug plan between 1991 and 2007 were eligible for inclusion. A multivariate logistic regression model was assembled to examine the relationship between dementia diagnosis, age, sex, other comorbidity, residence and osteoporosis medication dispensation. RESULTS: Almost half of the total osteoporosis cohort (n = 39 452) were dispensed an osteoporosis medication during the study period. Individuals with no dementia diagnosis were dispensed a medication significantly more often than those with a diagnosis of dementia (P < 0.001). Those patients with dementia (n = 13 315), who had been dispensed an osteoporosis drug, were more often younger, female, had not sustained a previous fracture, had ≥ 4 comorbid conditions and lived in the most central health region (P < 0.001). A diagnosis of dementia was found to be a significant negative predictor of osteoporosis drug dispensation (adjusted OR 0.55; 95% CI 0.44-0.69). Increasing comorbidity was significantly associated with receiving treatment (adjusted OR 3.30; 95% CI 2.88-3.78). CONCLUSION: Despite the wide availability of osteoporosis medications, our findings suggest that many older adults with a diagnosis of dementia, but not necessarily fewer comorbid conditions, were not receiving treatment.