It will come as no surprise to hear that low adherence to any type of medication can lead to incomplete treatment and disease recurrence. In the case of osteoporosis, patients failing to comply with their oral bisphosphonate treatment, which is prescribed to prevent a decrease in bone mass, will likely succumb to this same problem – which is concerning since a third to half of patients don’t fully adhere to their medication (1). In an attempt to curtail this low adherence, a research group from institutes across Europe and North America, in conjunction with the International Osteoporosis Foundation and European Calcified Tissue Society Working Group, has now recommended the implementation of a screening program for oral bisphosphonate adherence (2).
What might something like this – which on the face of it appears a gargantuan task – entail? They propose the measurement of two markers of the condition, levels of which are reduced by oral bisphosphonates – PINP (procollagen type 1 N-terminal propeptide) and CTX (collagen type 1 C-terminal telopeptide) – before therapy begins and then three months after its initiation. After collating their results, and referencing a study comparing three different oral bisphosphonate therapies (3), they came to recommend this: if there is a significant decrease in either biomarker (over 38 percent for PINP, and over 56 percent for CTX) then it appears that the patient is being compliant and therapy should be continued, but if there is no significant decrease, the clinician should reassess the situation to establish where the issue lies. The detection rate of this screening – which the researchers use synonymously with sensitivity – is 84 percent for PINP, 87 percent for CTX, and 94.5 percent if both are measured and changes are found in at least one of the biomarkers. Though their guidelines are empirically based, the researchers do not suggest that their recommendations will directly affect patient adherence to medication. Detecting the issue is a step in the right direction, but finding an effective solution to low adherence is a different puzzle to solve.
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References
- P Kothawala et al., “Systemic review and meta-analysis of real-world adherence to drug therapy for osteoporosis”, Mayo Clin Proc, 82, 1493–1501 (2007). PMID: 18053457. A Diez-Perez et al., “International Osteoporosis Foundation and European Calcified Tissue Society Working Groups. Recommendations for the screening of adherence to oral bisphosphonates”, Osteopor Int, 28, 767–774 (2017). PMID: 28093634. MA Paggiosi et al., “Comparison of the effects of three oral bisphosphonate therapies on the peripheral skeleton in postmenopausal osteoporosis: the TRIO study, Osteoposos Int, 25, 2729– 2741 (2014). PMID: 25074351.
