Kevin J Friesen1, Shawn Bugden1,2, Jamie Falk3. 1. College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, Apotex Centre, 750 McDermot Avenue, Winnipeg, MB, R3E 0T5, Canada. 2. School of Pharmacy, Memorial University, St. John's, NL, Canada. 3. College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, Apotex Centre, 750 McDermot Avenue, Winnipeg, MB, R3E 0T5, Canada. jamison.falk@umanitoba.ca.
Abstract
INTRODUCTION: This study aimed to examine long-term persistence in new users of oral bisphosphonates in a population-wide cohort in Manitoba, Canada. MATERIALS AND METHODS: A longitudinal observational study was conducted using administrative health data characterizing long-term bisphosphonate persistence in those who started treatment between 1997 and 2018. Treatment discontinuation was evaluated using Kaplan-Meier methods. Cox regression was used to examine associations between discontinuation and osteoporosis diagnosis, previous fractures, and age. A sub-analysis of users with FRAX scores examined the relationship between 10-year fracture risk estimations and discontinuation. RESULTS: Of 42,249 new bisphosphonate users, median age was 71 years, with 88.6% being female. Median duration of bisphosphonate use was 0.95 years (IQR 0.25, 3.9 years). Overall, 47.9% of incident users persisted up to 1 year, 25.0% persisted up to 3 years, and 14.1% up to 5 years. Presence of an indication for bisphosphonate use was associated with decreased discontinuation risk. Persistence generally increased with age. Having a BMD test performed was a predictor of lower discontinuation. The strongest predictor was having an osteoporosis diagnosis [HR for discontinuation = 0.68 (95% CI 0.66, 0.70)]. In users with FRAX scores (n = 14,114), moderate-risk [HR = 0.86 (95% CI 0.77, 0.96)] and high-risk users [HR = 0.77 (95% CI 0.69, 0.85)] were less likely to discontinue compared to lower-risk users. CONCLUSIONS: A rapid decline in bisphosphonate persistence was shown. Almost half of users would not be expected to achieve clinically relevant benefits with a persistence of less than 1 year. Allowing informed choice in high-risk patients may be the best way to focus on those likely to benefit and persist with treatment.
INTRODUCTION: This study aimed to examine long-term persistence in new users of oral bisphosphonates in a population-wide cohort in Manitoba, Canada. MATERIALS AND METHODS: A longitudinal observational study was conducted using administrative health data characterizing long-term bisphosphonate persistence in those who started treatment between 1997 and 2018. Treatment discontinuation was evaluated using Kaplan-Meier methods. Cox regression was used to examine associations between discontinuation and osteoporosis diagnosis, previous fractures, and age. A sub-analysis of users with FRAX scores examined the relationship between 10-year fracture risk estimations and discontinuation. RESULTS: Of 42,249 new bisphosphonate users, median age was 71 years, with 88.6% being female. Median duration of bisphosphonate use was 0.95 years (IQR 0.25, 3.9 years). Overall, 47.9% of incident users persisted up to 1 year, 25.0% persisted up to 3 years, and 14.1% up to 5 years. Presence of an indication for bisphosphonate use was associated with decreased discontinuation risk. Persistence generally increased with age. Having a BMD test performed was a predictor of lower discontinuation. The strongest predictor was having an osteoporosis diagnosis [HR for discontinuation = 0.68 (95% CI 0.66, 0.70)]. In users with FRAX scores (n = 14,114), moderate-risk [HR = 0.86 (95% CI 0.77, 0.96)] and high-risk users [HR = 0.77 (95% CI 0.69, 0.85)] were less likely to discontinue compared to lower-risk users. CONCLUSIONS: A rapid decline in bisphosphonate persistence was shown. Almost half of users would not be expected to achieve clinically relevant benefits with a persistence of less than 1 year. Allowing informed choice in high-risk patients may be the best way to focus on those likely to benefit and persist with treatment.