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Abstract
Objectives: To review trial-based economic evaluations, identifying: 1) the proportion reporting adherence; 2) methods for assigning intervention costs according to adherence; 3) which participants were included in the economic analysis; and 4) statistical methods to estimate cost-effectiveness in those who adhered. We provide recommendations on handling non-adherence in economic evaluations.
Methods: The NHS Economic Evaluation Database was searched for recently published trials. We extracted information on the methods used to assign shared costs in the presence of non-adherence and methods to account for non-adherence in the economic analysis.
Results: Ninety-six eligible trials were identified. For one-off interventions, 86% reported the number of participants initiating treatment. For recurring interventions, 56% and 73% respectively reported the number initiating and completing treatment, whilst 66% reported treatment intensity. Most studies (23/31 [74%] trials and 42/53 [79%] trials of one off and recurring interventions respectively) reported strict intention to treat or complete case analyses. A minority (3/31 [10%] and 7/53 [13%] respectively), however, performed a per protocol analysis. No studies used statistical methods to adjust for non-adherence directly in the economic evaluation. Only 13 studies described patient-level allocation of intervention costs; there was variation in how fixed costs were assigned according to adherence.
Conclusion. The majority of trials reported a measure of adherence, but reporting was not comprehensive. A non-trivial proportion of studies report a primary per protocol analysis which potentially produces biased results. Alongside primary ITT analysis, statistical methods for obtaining an unbiased estimate of cost-effectiveness in adherers should be considered.
Methods: The NHS Economic Evaluation Database was searched for recently published trials. We extracted information on the methods used to assign shared costs in the presence of non-adherence and methods to account for non-adherence in the economic analysis.
Results: Ninety-six eligible trials were identified. For one-off interventions, 86% reported the number of participants initiating treatment. For recurring interventions, 56% and 73% respectively reported the number initiating and completing treatment, whilst 66% reported treatment intensity. Most studies (23/31 [74%] trials and 42/53 [79%] trials of one off and recurring interventions respectively) reported strict intention to treat or complete case analyses. A minority (3/31 [10%] and 7/53 [13%] respectively), however, performed a per protocol analysis. No studies used statistical methods to adjust for non-adherence directly in the economic evaluation. Only 13 studies described patient-level allocation of intervention costs; there was variation in how fixed costs were assigned according to adherence.
Conclusion. The majority of trials reported a measure of adherence, but reporting was not comprehensive. A non-trivial proportion of studies report a primary per protocol analysis which potentially produces biased results. Alongside primary ITT analysis, statistical methods for obtaining an unbiased estimate of cost-effectiveness in adherers should be considered.
Original language | English |
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Pages (from-to) | 99-108 |
Number of pages | 10 |
Journal | Value in Health |
Volume | 19 |
Issue number | 1 |
Early online date | 16 Sep 2015 |
DOIs | |
Publication status | Published - 1 Jan 2016 |
Structured keywords
- ConDuCT-II
Keywords
- adherence
- compliance
- economic evaluation
- systematic review
- trial
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Dive into the research topics of 'The Reporting of Treatment Nonadherence and Its Associated Impact on Economic Evaluations Conducted Alongside Randomized Trials: A Systematic Review'. Together they form a unique fingerprint.Projects
- 2 Finished
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COLLABORATION AND INNOVATION IN DIFFICULT OR RANDOMISED CONTROLLED TRIALS
1/04/09 → 1/04/14
Project: Research