Adherence to oral glucose-lowering therapies and associations with 1-year HbA1c: A retrospective cohort analysis in a large primary care database

Andrew J. Farmer; Lauren R. Rodgers; Mike Lonergan; Beverley Shields; Michael N. Weedon; Louise Donnelly; Rury R. Holman; Ewan R. Pearson; Andrew T. Hattersley

doi:10.2337/dc15-1194

Adherence to oral glucose-lowering therapies and associations with 1-year HbA_1c: A retrospective cohort analysis in a large primary care database

Andrew J. Farmer (Lead / Corresponding author), Lauren R. Rodgers, Mike Lonergan, Beverley Shields, Michael N. Weedon, Louise Donnelly, Rury R. Holman, Ewan R. Pearson, Andrew T. Hattersley

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Abstract

Objective The impact of taking oral glucose-lowering medicines intermittently, rather than as recommended, is unclear. We conducted a retrospective cohort study using community-acquired U.K. clinical data (Clinical Practice Research Database [CPRD] and GoDARTS database) to examine the prevalence of nonadherence to treatment for type 2 diabetes and investigate its potential impact on HbA1c reduction stratified by type of glucose-lowering medication.

Research Design and Methods Data were extracted for patients treated between 2004 and 2014 who were newly prescribed metformin, sulfonylurea, thiazolidinedione, or dipeptidyl peptidase 4 inhibitors and who continued to obtain prescriptions over 1 year. Cohorts were defined by prescribed medication type, and good adherence was defined as a medication possession ratio ≥0.8. Linear regression was used to determine potential associations between adherence and 1-year baseline-adjusted HbA_1c reduction.

Results In CPRD and GoDARTS, 13% and 15% of patients, respectively, were nonadherent. Proportions of nonadherent patients varied by the oral glucose-lowering treatment prescribed (range 8.6% [thiazolidinedione] to 18.8% [metformin]). Nonadherent, compared with adherent, patients had a smaller HbA_1c reduction (0.4% [4.4 mmol/mol] and 0.46% [5.0 mmol/mol] for CPRD and GoDARTs, respectively). Difference in HbA_1c response for adherent compared with nonadherent patients varied by drug (range 0.38% [4.1 mmol/mol] to 0.75% [8.2 mmol/mol] lower in adherent group). Decreasing levels of adherence were consistently associated with a smaller reduction in HbA_1c.

Conclusions Reduced medication adherence for commonly used glucose-lowering therapies among patients persisting with treatment is associated with smaller HbA_1c reductions compared with those taking treatment as recommended. Differences observed in HbA_1c responses to glucose-lowering treatments may be explained in part by their intermittent use.

Original language	English
Pages (from-to)	258-263
Number of pages	6
Journal	Diabetes Care
Volume	39
Issue number	2
DOIs	https://doi.org/10.2337/dc15-1194
Publication status	Published - 1 Feb 2016

ASJC Scopus subject areas

Internal Medicine
Endocrinology, Diabetes and Metabolism
Advanced and Specialised Nursing

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.2337/dc15-1194Licence: Other

Author Accepted Manuscript
This is an author-created, un-copy-edited electronic version of an article accepted for publication in Diabetes Care. The American Diabetes Care Association (ADA), publisher of Diabetes Care, is not responsible for any errors or omissions in this version of the manuscript or any version derived from it by third parties. The definitive publisher-authenticated version will be available in a future issue of Diabetes Care in print and online at http://care.diabetesjournals.org,
Accepted author manuscript, 256 KBLicence: Other

Cite this

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title = "Adherence to oral glucose-lowering therapies and associations with 1-year HbA1c: A retrospective cohort analysis in a large primary care database",

abstract = "Objective The impact of taking oral glucose-lowering medicines intermittently, rather than as recommended, is unclear. We conducted a retrospective cohort study using community-acquired U.K. clinical data (Clinical Practice Research Database [CPRD] and GoDARTS database) to examine the prevalence of nonadherence to treatment for type 2 diabetes and investigate its potential impact on HbA1c reduction stratified by type of glucose-lowering medication. Research Design and Methods Data were extracted for patients treated between 2004 and 2014 who were newly prescribed metformin, sulfonylurea, thiazolidinedione, or dipeptidyl peptidase 4 inhibitors and who continued to obtain prescriptions over 1 year. Cohorts were defined by prescribed medication type, and good adherence was defined as a medication possession ratio ≥0.8. Linear regression was used to determine potential associations between adherence and 1-year baseline-adjusted HbA1c reduction. Results In CPRD and GoDARTS, 13% and 15% of patients, respectively, were nonadherent. Proportions of nonadherent patients varied by the oral glucose-lowering treatment prescribed (range 8.6% [thiazolidinedione] to 18.8% [metformin]). Nonadherent, compared with adherent, patients had a smaller HbA1c reduction (0.4% [4.4 mmol/mol] and 0.46% [5.0 mmol/mol] for CPRD and GoDARTs, respectively). Difference in HbA1c response for adherent compared with nonadherent patients varied by drug (range 0.38% [4.1 mmol/mol] to 0.75% [8.2 mmol/mol] lower in adherent group). Decreasing levels of adherence were consistently associated with a smaller reduction in HbA1c.Conclusions Reduced medication adherence for commonly used glucose-lowering therapies among patients persisting with treatment is associated with smaller HbA1c reductions compared with those taking treatment as recommended. Differences observed in HbA1c responses to glucose-lowering treatments may be explained in part by their intermittent use.",

author = "Farmer, {Andrew J.} and Rodgers, {Lauren R.} and Mike Lonergan and Beverley Shields and Weedon, {Michael N.} and Louise Donnelly and Holman, {Rury R.} and Pearson, {Ewan R.} and Hattersley, {Andrew T.}",

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AU - Farmer, Andrew J.

AU - Rodgers, Lauren R.

AU - Lonergan, Mike

AU - Shields, Beverley

AU - Weedon, Michael N.

AU - Donnelly, Louise

AU - Holman, Rury R.

AU - Pearson, Ewan R.

AU - Hattersley, Andrew T.

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N2 - Objective The impact of taking oral glucose-lowering medicines intermittently, rather than as recommended, is unclear. We conducted a retrospective cohort study using community-acquired U.K. clinical data (Clinical Practice Research Database [CPRD] and GoDARTS database) to examine the prevalence of nonadherence to treatment for type 2 diabetes and investigate its potential impact on HbA1c reduction stratified by type of glucose-lowering medication. Research Design and Methods Data were extracted for patients treated between 2004 and 2014 who were newly prescribed metformin, sulfonylurea, thiazolidinedione, or dipeptidyl peptidase 4 inhibitors and who continued to obtain prescriptions over 1 year. Cohorts were defined by prescribed medication type, and good adherence was defined as a medication possession ratio ≥0.8. Linear regression was used to determine potential associations between adherence and 1-year baseline-adjusted HbA1c reduction. Results In CPRD and GoDARTS, 13% and 15% of patients, respectively, were nonadherent. Proportions of nonadherent patients varied by the oral glucose-lowering treatment prescribed (range 8.6% [thiazolidinedione] to 18.8% [metformin]). Nonadherent, compared with adherent, patients had a smaller HbA1c reduction (0.4% [4.4 mmol/mol] and 0.46% [5.0 mmol/mol] for CPRD and GoDARTs, respectively). Difference in HbA1c response for adherent compared with nonadherent patients varied by drug (range 0.38% [4.1 mmol/mol] to 0.75% [8.2 mmol/mol] lower in adherent group). Decreasing levels of adherence were consistently associated with a smaller reduction in HbA1c.Conclusions Reduced medication adherence for commonly used glucose-lowering therapies among patients persisting with treatment is associated with smaller HbA1c reductions compared with those taking treatment as recommended. Differences observed in HbA1c responses to glucose-lowering treatments may be explained in part by their intermittent use.

AB - Objective The impact of taking oral glucose-lowering medicines intermittently, rather than as recommended, is unclear. We conducted a retrospective cohort study using community-acquired U.K. clinical data (Clinical Practice Research Database [CPRD] and GoDARTS database) to examine the prevalence of nonadherence to treatment for type 2 diabetes and investigate its potential impact on HbA1c reduction stratified by type of glucose-lowering medication. Research Design and Methods Data were extracted for patients treated between 2004 and 2014 who were newly prescribed metformin, sulfonylurea, thiazolidinedione, or dipeptidyl peptidase 4 inhibitors and who continued to obtain prescriptions over 1 year. Cohorts were defined by prescribed medication type, and good adherence was defined as a medication possession ratio ≥0.8. Linear regression was used to determine potential associations between adherence and 1-year baseline-adjusted HbA1c reduction. Results In CPRD and GoDARTS, 13% and 15% of patients, respectively, were nonadherent. Proportions of nonadherent patients varied by the oral glucose-lowering treatment prescribed (range 8.6% [thiazolidinedione] to 18.8% [metformin]). Nonadherent, compared with adherent, patients had a smaller HbA1c reduction (0.4% [4.4 mmol/mol] and 0.46% [5.0 mmol/mol] for CPRD and GoDARTs, respectively). Difference in HbA1c response for adherent compared with nonadherent patients varied by drug (range 0.38% [4.1 mmol/mol] to 0.75% [8.2 mmol/mol] lower in adherent group). Decreasing levels of adherence were consistently associated with a smaller reduction in HbA1c.Conclusions Reduced medication adherence for commonly used glucose-lowering therapies among patients persisting with treatment is associated with smaller HbA1c reductions compared with those taking treatment as recommended. Differences observed in HbA1c responses to glucose-lowering treatments may be explained in part by their intermittent use.

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Adherence to oral glucose-lowering therapies and associations with 1-year HbA_1c: A retrospective cohort analysis in a large primary care database

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Stratified Medicine in Type 2 Diabetes: Insights from the Study of Drug Response (New Investigator Award)

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Adherence to oral glucose-lowering therapies and associations with 1-year HbA1c: A retrospective cohort analysis in a large primary care database

Abstract

ASJC Scopus subject areas

UN SDGs

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Stratified Medicine in Type 2 Diabetes: Insights from the Study of Drug Response (New Investigator Award)

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Adherence to oral glucose-lowering therapies and associations with 1-year HbA_1c: A retrospective cohort analysis in a large primary care database