Chest
Volume 140, Issue 2, August 2011, Pages 425-432
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Original Research
Respiratory Care
Accurate Assessment of Adherence: Self-Report and Clinician Report vs Electronic Monitoring of Nebulizers

https://doi.org/10.1378/chest.09-3074Get rights and content

Background

People with cystic fibrosis have a high treatment burden. While uncertainty remains about individual patient level of adherence to medication, treatment regimens are difficult to tailor, and interventions are difficult to evaluate. Self- and clinician-reported measures are routinely used despite criticism that they overestimate adherence. This study assessed agreement between rates of adherence to prescribed nebulizer treatments when measured by self-report, clinician report, and electronic monitoring suitable for long-term use.

Methods

Seventy-eight adults with cystic fibrosis were questioned about their adherence to prescribed nebulizer treatments over the previous 3 months. Self-report was compared with clinician report and stored adherence data downloaded from the I-Neb nebulizer system. Adherence measures were expressed as a percentage of the prescribed regimen, bias was estimated by the paired difference in mean (95% CI) patient and clinician reported and actual adherence. Agreement between adherence measures was calculated using intraclass correlation coefficients (95% CI), and disagreements for individuals were displayed using Bland-Altman plots.

Results

Patient-identified prescriptions matched the medical record prescription. Median self-reported adherence was 80% (interquartile range, 60%-95%), whereas median adherence measured by nebulizer download was 36% (interquartile range, 5%-84.5%). Nine participants overmedicated and underreported adherence. Median clinician report ranged from 50% to 60%, depending on profession. Extensive discrepancies between self-report and clinician report compared with nebulizer download were identified for individuals.

Conclusions

Self- and clinician-reporting of adherence does not provide accurate measurement of adherence when compared with electronic monitoring. Using inaccurate measures has implications for treatment burden, clinician prescribing practices, cost, and accuracy of trial data.

Section snippets

Materials and Methods

A cross-sectional comparison of three approaches to measuring adherence (self-report, clinician report, and electronic monitoring through the I-Neb) was undertaken at the Leeds regional CF unit in England. Ethical approval for this study was obtained from the relevant National Health Service local research ethics committee.

Results

Eighty-one patients brought their I-Neb systems to the clinic within the study period, and 80 gave informed consent to take part in the study. Downloaded data could not be obtained in one case because the I-Neb was an older model without the capability to download data and in one case because of malfunction following ingress of water. Data for 78 participants, therefore, were analyzed (Fig 1). Complete data were collected for 63 participants; 15 participants had missing data for the ward nurse

Discussion

Previous studies have shown important differences in the level of patient adherence to treatments when adherence was assessed by reported methods or by electronic monitoring. Nonetheless, report-based estimates of adherence continue to inform important treatment decisions, such as whether to intensify treatment or whether a patient is suitable for further interventions, including transplantation. The present study was designed to directly assess the commonly used adherence measures of

Acknowledgments

Author contributions: Ms Daniels had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Ms Daniels: contributed to the concept for this research; wrote the proposal and submitted it to the ethics committee; made amendments for ethics committee acceptance; carried out data collection; analyzed data with guidance, correction, and assistance from Dr Sutton; and wrote and made amendments to this manuscript based

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    Parts of this article have been presented in abstract form (Hughes TE, Pollard K, Black A, Conway SP, Peckham DG. Reported and objective adherence to nebulised therapy in adults with cystic fibrosis [Abstract S64]. J Cyst Fibros. 2008;7[suppl 2]:256 and Hughes TE, Pollard K, Goodacre L, Sutton C, Conway SP, Peckham D. Variation in bias of self-reported adherence to nebulizers in adults with cystic fibrosis [Abstract S92]. J Cyst Fibros. 2009;8[suppl 2]:370).

    Funding/Support: The authors have reported to CHEST that no funding was received for this study.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).

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