Osteoporosis telephonic intervention to improve medication regimen adherence: a large, pragmatic, randomized controlled trial

Abstract

Background: Multiple studies demonstrate poor adherence to medication regimens prescribed for chronic illnesses, including osteoporosis, but few interventions have been proven to enhance adherence. We examined the effectiveness of a telephone-based counseling program rooted in motivational interviewing to improve adherence to a medication regimen for osteoporosis.

Methods: We conducted a 1-year randomized controlled clinical trial. Participants were recruited from a large pharmacy benefits program for Medicare beneficiaries. All potentially eligible individuals had been newly prescribed a medication for osteoporosis. Consenting participants were randomized to a program of telephone-based counseling (n = 1046) using a motivational interviewing framework or a control group (n = 1041) that received mailed educational materials. Medication regimen adherence was the primary outcome compared across treatment arms and was measured as the median (interquartile range) medication possession ratio, calculated as the ratio of days with filled prescriptions to total days of follow-up.

Results: The groups were balanced at baseline, with a mean age of 78 years; 93.8% were female. In an intention-to-treat analysis, median adherence was 49% (interquartile range, 7%-88%) in the intervention arm and 41% (2%-86%) in the control arm (P = .07, Kruskal-Wallis test). There were no differences in self-reported fractures.

Conclusion: In this randomized controlled trial, we did not find a statistically significant improvement in adherence to an osteoporosis medication regimen using a telephonic motivational interviewing intervention.

Trial registration: ClinicalTrials.gov NCT00567294.

Figure 1

The CONSORT diagram illustrates the assembly of the study cohort and its follow-up through the trial procedures. Ten subjects (4 in the intervention arm and 6 in the control arm) died between recruitment and the start of follow-up 30 days later and were excluded from analyses.

Figure 2

This histogram displays the distribution of adherence for intervention (white) and control arm (grey), by decile of medication possession ratio.

Figure 3

This histogram displays the median medication possession ratios for six 60-day intervals, by treatment assignment, with intervention in purple and control in red. The interaction effect between treatment arm and sequential 60-day periods during follow-up was not statistically significant (P for interaction = 0.60).

Figure 4

This figure illustrates the persistence over time in use of medications for osteoporosis. The intervention arm is show in red and the control arm in blue.