Factors associated with initiation of bone-health medication among older adults in primary care in Ireland

Background Adults at high risk of fragility fracture should be offered pharmacological treatment when not contraindicated, however under-treatment is common. Objective This study aimed to investigate factors associated with bone-health medication initiation in older patients attending primary care. Design Retrospective cohort study. Setting 44 general practices in Ireland from 2011-2017. Subjects Adults aged ≥65 years who were naïve to bone-health medication for 12 months. Methods Overall fracture-risk (based on QFracture) and individual fracture-risk factors were described for patients initiated and not initiated onto medication and compared using generalised linear model regression with Poisson distribution. Results Of 36,799 patients (51 % female, mean age 75.4 (SD=8.4)) included, 8% (n=2,992) were observed to initiate on bone-health medication during the study. One fifth of all patients (n=8,193) had osteoporosis or had high fracture-risk but only 21% of them (n=1,687) initiated on medication. Female sex, older age, state-funded health cover and osteoporosis were associated with initiation. Independently of osteoporosis and co-variates, high 5-year QFracture risk for hip (IRR=1.33 (95% CI=1.17-1.50), p<0.01) and all fractures (IRR=1.30 (95% CI=1.17-1.44), p<0.01) were associated with medication initiation. Previous fracture, rheumatoid arthritis, and corticosteroid use were associated with initiation, while liver, kidney, cardiovascular disease, diabetes and oestrogen-only hormone replacement therapy showed an inverse association. Conclusions Bone-health medication initiation is targeted at patients at higher fracture-risk but much potential under-treatment remains, particularly in those >80 years and with co-morbidities. This may reflect clinical uncertainty in older multimorbid patients, and further research should explore decision-making in preventive bone medication prescribing. Key points During this study, 23% of women and 11% of men defined as high-risk of fracture were newly initiated on bone-health medication. Rates of potential under-treatment were highest in patients over 80 years old. Fracture history, corticosteroid use, and rheumatoid arthritis were independently associated with medication initiation. Patients with diabetes, and liver, kidney, or cardiovascular disease were less likely to be initiated on medication. Clinical guidelines should provide advice on risk-benefit decisions in osteoporosis treatment where co-morbidities are present.