Interventions to improve adherence and persistence with osteoporosis medications: a systematic literature review

Abstract

Summary

Adherence and persistence with osteoporosis medications are poor. We conducted a systematic literature review of interventions to improve adherence and persistence with osteoporosis medications. Seven studies met eligibility requirements and were included in the review. Few interventions were efficacious, and no clear trends regarding successful intervention techniques were identified. However, periodic follow-up interaction between patients and health professionals appeared to be beneficial.

Introduction

Adherence and persistence with pharmacologic therapy for osteoporosis are suboptimal. Our goal was to examine the design and efficacy of published interventions to improve adherence and persistence.

Methods

We searched medical literature databases for English-language papers published between January 1990 and July 2008. We selected papers that described interventions and provided results for control and intervention subjects. We assessed the design and methods of each study, including randomization, blinding, and reporting of drop-outs. We summarized the results and calculated effect sizes for each trial.

Results

Seven studies met eligibility requirements and were included in the review. Five of the seven studies provided adherence data. Of those five studies, three showed a statistically significant (p ≤ 0.05) improvement in adherence by the intervention group, with effect sizes from 0.17 to 0.58. Five of the seven studies provided persistence data. Of those five, one reported statistically significant improvement in persistence by the intervention group, with an effect size of 0.36.

Conclusions

Few interventions were efficacious, and no clear trends regarding successful intervention techniques were identified in this small sample of studies. However, periodic follow-up interaction between patients and health professionals appeared to be beneficial.

Appendix 1. Calculations of Effect Size

For the studies (Delmas et al., Cook et al., Cooper et al., Guilera et al., Schousboe et al., Clowes et al.) for which we had the proportions (P) of the intervention and control populations who were adherent or persistent, the following calculation was used to determine effect size:

$$ {\text{Effect size}} = 2\left( {\arcsin \sqrt {P_{{\text{int} ervention}} } } \right) - 2\left( {\arcsin \sqrt {P_{control} } } \right) $$

For the study (Shu et al.) for which we had the means (M) and standard deviations (σ) for adherence and persistence in the intervention and control populations, the following calculation was used to determine effect size:

$$ {\text{Effect size}} = {{\left| {M_{\text{intervention}} - M_{\text{control}} } \right|} \mathord{\left/ {\vphantom {{\left| {M_{\text{intervention}} - M_{\text{control}} } \right|} {\sigma_{\text{control}} }}} \right. } {\sigma_{\text{control}} }} $$

As a general guideline, effect sizes ≅0.20 are considered to have negligible clinical importance; ≅0.50 moderate clinical importance; and ≅0.80 crucial clinical importance (see also Cohen 1987 [20]).