Osteoporosis treatment: Systematic global review of intervention thresholds based on FRAX

Since its launch in 2008, FRAX^® has become a widely used assessment tool in clinical practice and is included in many national osteoporosis management guidelines worldwide. Specific calculators are currently available for 58 countries and in 32 languages at http://www.shef.ac.uk/FRAX/.

According to most current guidelines, treatment for osteoporosis is recommended in individuals with prior fragility fractures -- however for those without prior fractures, intervention thresholds using FRAX can be derived using different methods.

The new report 'Systematic review of intervention thresholds based on FRAX', published recently in Archives of Osteoporosis on behalf of the International Osteoporosis Foundation (IOF) and the National Osteoporosis Guideline Group (NOGG), provides a systematic review of the available information on the use of FRAX in assessment guidelines, and in particular the setting of intervention thresholds and their validation.

The report includes information on, and worldwide examples of:

• the use of a fixed FRAX intervention threshold;
• age-dependent intervention thresholds using FRAX;
• hybrid intervention thresholds using FRAX;
• health economic approach to intervention thresholds with FRAX;
• discrimination of FRAX (comparing cohort-specific models with FRAX);
• calibration of FRAX.

Among its many conclusions and recommendations, the report finds that fixed or age-dependent thresholds are more effective in identifying individuals at high risk of fracture than the use of BMD alone, however the intervention thresholds must be country-specific.

More than one half (39) of the 58 publications identified utilized a threshold probability of 20 % for a major osteoporotic fracture- In nearly all instances, no rationale is provided other than that this was the threshold used by the National Osteoporosis Foundation of the US.

Lead-author of the report, John A. Kanis, Emeritus Professor in Human Metabolism at the University of Sheffield, commented, "Given the wide variation in fracture probability globally, it is important that intervention thresholds are appropriate to the population of the country concerned."

Professor Kanis added, "Importantly, of the 120 guidelines or academic papers that incorporated FRAX, 38 provided no clear statement on how the fracture probabilities derived are to inform the approach to therapy, a situation clearly frustrating for the clinician. Linkage of the FRAX calculator to country-specific intervention thresholds, as now available the UK, Finland, Lebanon and Romania, provides a ready solution."