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.