Reliability of self-reported recent antibiotic use among the general population: a methodological issue
Authors: S. Sabour
Journal: Clinical Microbiology and Infection (2017)

I was interested to read the paper by Demore et al. [[1]Demoré B. Le Govic D. Thilly N. Boivin J.M. Pulcini C. Reliability of self-reported recent antibiotic use among the general population: a cross-sectional study.Clin Microbiol Infect. 2017; 23 (486.e7–12)Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar], the purpose of which was to evaluate the reliability of self-reported recent antibiotic use, including the ability to name the antibiotic, among pharmacy customers from the general population [[1]Demoré B. Le Govic D. Thilly N. Boivin J.M. Pulcini C. Reliability of self-reported recent antibiotic use among the general population: a cross-sectional study.Clin Microbiol Infect. 2017; 23 (486.e7–12)Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar]. Their study took place in pharmacies in northeastern France from January to April 2016. Participants were asked if they had used any antibiotics in the preceding 4 months and if so, to name them. Their reports were compared with an electronic pharmacy dispensing record listing all of the medication dispensed to them in France [[1]Demoré B. Le Govic D. Thilly N. Boivin J.M. Pulcini C. Reliability of self-reported recent antibiotic use among the general population: a cross-sectional study.Clin Microbiol Infect. 2017; 23 (486.e7–12)Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar]. Based on their results, agreement between self-report and the electronic record about whether or not they had used an antibiotic was 80% (κ 0.60). Among the discordant responses, 57% (81/143) involved under-reporting. Only 24% (79/325) of the patients could name the antibiotic for each course of treatment; 49% (160/325) could not. Applying κ is one of the methodological mistakes in reliability analysis for qualitative outcomes. Two important weaknesses of κ statistics to assess agreement are as follows. It depends upon the prevalence in each category, which means that the κ value for 80% concordant cells with prevalence of 70% and 10% is poor, whereas for the same 80% with prevalence of 40% and 40% it is moderate to good (the κ value also depends upon the number of categories [2Thompson W.D. Walter S.D. Kappa and the concept of independent errors.J Clin Epidemiol. 1988; 41: 969-970Abstract Full Text PDF PubMed Scopus (38) Google Scholar, 3Vanbelle S. A new interpretation of the weighted kappa coefficients.Psychometrika. 2016; 81: 399-410Crossref PubMed Scopus (73) Google Scholar, 4Sabour S. Reproducibility of semi-automatic coronary plaque quantification in coronary CT angiography with sub-mSv radiation dose; common mistakes.J Cardiovasc Comput Tomogr. 2016; 10: e21-e22Abstract Full Text Full Text PDF PubMed Scopus (40) Google Scholar, 5Sabour S. Reliability of SleepStrip as a screening test in obstructive sleep apnea patients: methodological issues to avoid misinterpretation.Eur Arch Otorhinolaryngol. 2015; 272: 1299-1300Crossref PubMed Scopus (2) Google Scholar, 6Sabour S. Reliability of categorical loudness scaling in the electrical domain: common mistakes.Int J Audiol. 2014; 53: 836-837Crossref PubMed Scopus (2) Google Scholar]). Therefore, using weighted κ in such situations can be suggested as a statistical test. Linearly weighted κ is a weighted average of the κ of the 2-by-2 agreement matrices, whereas the quadratically weighted κ is insensitive to the agreement matrices that are row- or column-reflection symmetric. Therefore, a rank-one matrix decomposition approach to the weighting schemes can demonstrate these phenomena in a concise manner [[3]Vanbelle S. A new interpretation of the weighted kappa coefficients.Psychometrika. 2016; 81: 399-410Crossref PubMed Scopus (73) Google Scholar]. They concluded that participants' self-reports are relatively reliable for their recent use of an antibiotic, but not for its name. Such conclusion should be supported by the above-mentioned methodological and statistical issues. Otherwise, in routine clinical care, mismanagement of the patients may occur. There were no conflicts of interest and no external funding was received. Reliability of self-reported recent antibiotic use among the general population: a cross-sectional study: author's responseClinical Microbiology and InfectionVol. 24Issue 1PreviewWe thank Dr S. Sabour for showing interest in our article and for giving us the opportunity to clarify some aspects of the statistics used in our study [1,2]. Full-Text PDF Open Archive