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Analyzing adherence to prenatal supplement: does pill count measure up?
Kristie E Appelgren1, Paul J Nietert, Thomas C Hulsey
1Department of Pediatrics, Duke University, Durham, NC 27710, USA.
International Journal of Endocrinology
|February 20, 2010
Summary
Pill counts are an unreliable measure of adherence to vitamin D supplements, according to a new study. Serum metabolite levels provide a more accurate assessment of patient adherence in clinical research.
Area of Science:
- Clinical Research
- Nutritional Science
- Pharmacology
Background:
- Accurate measurement of patient adherence is crucial for determining medication efficacy.
- Pill counts are a common but potentially flawed method for assessing adherence.
- Novel adherence metrics are needed, especially for supplements with long half-lives.
Purpose of the Study:
- To evaluate the association between adherence measured by pill counts and serum-based adherence metrics.
- To assess the reliability of pill counts as a predictor of adherence to vitamin D supplementation.
Main Methods:
- Utilized data from a prenatal vitamin D supplementation trial with three dosing groups.
- Compared adherence via pill counts to a novel serum-based definition using 25-hydroxy-vitamin D (25-OH-D) levels.
- Employed multivariate logistic regression to analyze the association between pill count adherence and serum metabolite levels.
Main Results:
- Mean adherence percentage by pill count was not a significant predictor of adherence determined by serum metabolite levels.
- This finding remained consistent across multiple sensitivity analyses.
- Pill count adherence did not reliably reflect adherence to the study protocol.
Conclusions:
- Pill counts are not a reliable measure of adherence for long half-life supplements like vitamin D.
- The study highlights the need to re-evaluate adherence measurement methods in clinical research.
- Serum metabolite levels offer a more accurate alternative for assessing adherence to supplements and medications.
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