Analyzing Adherence to Prenatal Supplement: Does Pill Count Measure Up?

Objective. To determine if adherence as measured by pill count would show a significant association with serum-based measures of adherence. Methods. Data were obtained from a prenatal vitamin D supplementation trial where subjects were stratified by race and randomized into three dosing groups: 400...

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Main Authors: Kristie E. Appelgren, Paul J. Nietert, Thomas C. Hulsey, Bruce W. Hollis, Carol L. Wagner
Format: Article
Language:English
Published: Wiley 2010-01-01
Series:International Journal of Endocrinology
Online Access:http://dx.doi.org/10.1155/2010/631971
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author Kristie E. Appelgren
Paul J. Nietert
Thomas C. Hulsey
Bruce W. Hollis
Carol L. Wagner
author_facet Kristie E. Appelgren
Paul J. Nietert
Thomas C. Hulsey
Bruce W. Hollis
Carol L. Wagner
author_sort Kristie E. Appelgren
collection DOAJ
description Objective. To determine if adherence as measured by pill count would show a significant association with serum-based measures of adherence. Methods. Data were obtained from a prenatal vitamin D supplementation trial where subjects were stratified by race and randomized into three dosing groups: 400 (control), 2000, or 4000 IU vitamin D3/day. One measurement of adherence was obtained via pill counts remaining compared to a novel definition for adherence using serum 25-hydroxy-vitamin D (25-OH-D) levels (absolute change in 25(OH)D over the study period and the subject's steady-state variation in their 25(OH)D levels). A multivariate logistic regression model examined whether mean percent adherence by pill count was significantly associated with the adherence measure by serum metabolite levels. Results. Subjects' mean percentage of adherence by pill count was not a significant predictor of adherence by serum metabolite levels. This finding was robust across a series of sensitivity analyses. Conclusions. Based on our novel definition of adherence, pill count was not a reliable predictor of adherence to protocol, and calls into question how adherence is measured in clinical research. Our findings have implications regarding the determination of efficacy of medications under study and offer an alternative approach to measuring adherence of long half-life supplements/medications.
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series International Journal of Endocrinology
spelling doaj-art-b00de22dafa74efba3b164c350187e402025-02-03T05:58:59ZengWileyInternational Journal of Endocrinology1687-83371687-83452010-01-01201010.1155/2010/631971631971Analyzing Adherence to Prenatal Supplement: Does Pill Count Measure Up?Kristie E. Appelgren0Paul J. Nietert1Thomas C. Hulsey2Bruce W. Hollis3Carol L. Wagner4Department of Pediatrics, Duke University, Durham, NC 27710, USADepartment of Biostatistics, Bioinformatics, and Epidemiology, Medical University of South Carolina, Charleston, SC 29425, USADivision of Neonatology, Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, USADivision of Neonatology, Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, USADivision of Neonatology, Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, USAObjective. To determine if adherence as measured by pill count would show a significant association with serum-based measures of adherence. Methods. Data were obtained from a prenatal vitamin D supplementation trial where subjects were stratified by race and randomized into three dosing groups: 400 (control), 2000, or 4000 IU vitamin D3/day. One measurement of adherence was obtained via pill counts remaining compared to a novel definition for adherence using serum 25-hydroxy-vitamin D (25-OH-D) levels (absolute change in 25(OH)D over the study period and the subject's steady-state variation in their 25(OH)D levels). A multivariate logistic regression model examined whether mean percent adherence by pill count was significantly associated with the adherence measure by serum metabolite levels. Results. Subjects' mean percentage of adherence by pill count was not a significant predictor of adherence by serum metabolite levels. This finding was robust across a series of sensitivity analyses. Conclusions. Based on our novel definition of adherence, pill count was not a reliable predictor of adherence to protocol, and calls into question how adherence is measured in clinical research. Our findings have implications regarding the determination of efficacy of medications under study and offer an alternative approach to measuring adherence of long half-life supplements/medications.http://dx.doi.org/10.1155/2010/631971
spellingShingle Kristie E. Appelgren
Paul J. Nietert
Thomas C. Hulsey
Bruce W. Hollis
Carol L. Wagner
Analyzing Adherence to Prenatal Supplement: Does Pill Count Measure Up?
International Journal of Endocrinology
title Analyzing Adherence to Prenatal Supplement: Does Pill Count Measure Up?
title_full Analyzing Adherence to Prenatal Supplement: Does Pill Count Measure Up?
title_fullStr Analyzing Adherence to Prenatal Supplement: Does Pill Count Measure Up?
title_full_unstemmed Analyzing Adherence to Prenatal Supplement: Does Pill Count Measure Up?
title_short Analyzing Adherence to Prenatal Supplement: Does Pill Count Measure Up?
title_sort analyzing adherence to prenatal supplement does pill count measure up
url http://dx.doi.org/10.1155/2010/631971
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