Reassessment Intervals for Transition From Low to High Fracture Risk Among Adults Older Than 50 Years

Abstract

IMPORTANCE Fracture risk scores are used to identify individuals at high risk of major osteoporotic fracture or hip fracture for antiosteoporosis treatment. For those not meeting treatment thresholds at baseline, the optimal interval for reassessing fracture risk is uncertain.OBJECTIVE To examine reassessment intervals for transition from low to high fracture risk under guidelines-defined treatment thresholds. DESIGN, SETTING, AND PARTICIPANTSThis retrospective cohort study included persons aged 50 years or older with fracture risk below treatment thresholds at baseline who had fracture risk reassessed at least 1 year later. Data were obtained from a population-based bone mineral density registry (baseline assessment during 1996-2015; reassessment to 2016) in the Province of Manitoba, Canada. Primary analysis was performed from May to June 2019. Analysis for the revision was performed in October 2019. MAIN OUTCOMES AND MEASURES The primary outcome was time to transition from low (below the treatment threshold) to high fracture risk (treatment-qualifying risk score using osteoporosis clinical practice guidelines strategies for Canada, the United States, and the United Kingdom). RESULTS The study population consisted of 10 564 individuals (94.1% women; mean [SD] age at baseline, 63.2 [8.2] years). At the time of reassessment (a mean [SD] interval of 5.2 [2.9] yearsbetween initial and subsequent fracture risk assessment), 690 (6.6%) had reached the fixed major osteoporotic fracture treatment threshold of 20%, 1546 (16.2%) had reached the fixed hip treatment threshold of 3%, and 932 (9.4%) had reached the age-dependent major osteoporotic fracture treatment threshold. Among those below 25% of the treatment threshold at baseline for each guideline, few (0%-3.0%) reached guidelines-defined high fracture risk at follow-up. In contrast, among those at the upper end of the scale for each guideline (75%-99% of the treatment threshold at baseline), 30.6% to 74.4% reached guidelines-defined high fracture risk. An increased number of clinical risk factors was associated with increased likelihood of reaching guidelines-defined high fracture risk (range for 3 guidelines, 17.1%-28.2%) compared with unchanged or decreased clinical risk factors (range for 3 guidelines, 3.3%-12.8%) (P < .001). Estimated time for 10% of the population to reach treatment-qualifying high fracture risk ranged from fewer than 3 years to more than 15 years. CONCLUSIONS AND RELEVANCEThe findings suggest that baseline fracture risk (as a fraction of the treatment threshold) and change in clinical risk factors can identify individuals with low and high probability of guidelines-defined high fracture risk during follow-up, thereby potentially helping to inform the reassessment interval. Question What is the optimal reassessment interval to detect high fracture risk for those who do not meet the treatment threshold at baseline? Findings In this cohort study of 10 564 individuals, after a mean interval of 5.2 years between initial and subsequent fracture risk a...

Serial Bone Density Measurement for Osteoporosis Screening

“…For patients with 10-year predicted risk below the treatment threshold (20% for major osteoporotic fracture or 3% for hip fracture) at baseline, age was a key factor, with the estimated time to treatment–level fracture risk ranging from 7.6 years for women aged 65 to 69 years to 5.1 years for women aged 75 to 79 years at baseline (not accurately estimated for women aged 50-64 years because of rare incidence of treatment-level scores) . In a clinical registry of 10 564 individuals reassessed after mean 5.2 years, baseline risk that was only slightly below the treatment threshold, and the acquisition of new clinical risk factors during follow-up were associated with reduced time to treatment qualification . Together, these measures identified subgroups of patients for whom the transition to guidelines–defined high fracture risk was unlikely for more than 15 years and others for whom the transition to high risk occurred in less than 3 years (Table).…”