Measuring and improving adherence to osteoporosis pharmacotherapy

Abstract

Purpose of review: Osteoporosis is a major public health issue resulting in considerable fracture-related morbidity. Although effective treatment exists, adherence to osteoporosis pharmacotherapy is suboptimal and linked to reduced drug effectiveness. In this paper, we review methods of measuring and improving adherence to osteoporosis pharmacotherapy.

Recent findings: Most patients will stop osteoporosis pharmacotherapy, yet the majority who discontinue will reinitiate treatment after an extended gap. The key to improving adherence to osteoporosis pharmacotherapy is to reduce the number and length of gaps in treatment. Multifaceted and individualized interventions may help to improve adherence. New strategies aimed at identifying patients likely to stop therapy may also facilitate the development of targeted interventions.

Summary: Adherence to osteoporosis pharmacotherapy is suboptimal with short periods of persistence and lengthy gaps in therapy. Regular communication regarding the importance of continued therapy is critical. More research to help identify risk profiles of patients likely to become nonadherent, targeted multifaceted interventions to maximize adherence to therapy, and data to support when patients may safely consider a physician directed drug holiday is needed.

Figure 1

Quantifying adherence to pharmacotherapy using healthcare utilization data, adapted from prior summaries[18, 25]. Adherence is a general term describing medication taking behaviour and is examined using healthcare utilization data by measurement of compliance and persistence in the observation period. The proportion of days covered (PDC) is also commonly referred to as the medication possession ratio (MPR). We recommend PDC as the standard terminology and measurement of compliance. t₀=start of observation period t₁=end of observation period

Figure 2

Example drug exposure and adherence for a hypothetical patient. A. Truth: dark solid lines=true consumption B. Claims data “raw”: dark solid lines=drug use identified through pharmacy claims, dotted line=days in hospital identified through medical claims. C. Claims data “raw” +50% days supplied grace period: dark solid lines=drug use identified through raw pharmacy claims, light solid lines=coverage added by applying a maximum 50% days supplied grace period to all gaps, dotted line=days in hospital identified through medical claims. t₀=start of observation period, t₁=end of observation period; calculations only consider drug coverage during the observation period