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Reporting on health equity requires addressing measurement issues

Posted by jscanlan on 27 Jan 2013 at 19:30 GMT

On 3 November 2012, I posted a comment pertaining to this article in connection with the editorial addressing the article.[1] The comment discusses, inter alia, the need for analyses of health equity issues to consider the ways standard measures of differences between outcome rates tend to be affected by the prevalence of an outcome, including the pattern by which relative differences in favorable outcomes and relative differences in corresponding adverse outcomes tend to change in the opposite direction as the prevalence of an outcome changes. On 10 January 2013, the authors of this article posted a reply to the comment on the editorial.[2] The comment and reply both shed additional light on the instant article.

1. Scanlan JP. Clarity in the reporting of health equity issues requires addressing measurement issues. PLoS Medicine Nov. 3, 2012 ( responding to The PLOS Medicine Editors (2012) Bringing Clarity to the Reporting of Health Equity. PLoS Med 9(10): e1001334. doi:10.1371/journal.pmed.1001334): http://www.plosmedicine.o...

2. Welch V(on behalf of the author team). Reply to Mr. Scanlan. 10 Jan 2013: http://www.plosmedicine.o...

No competing interests declared.

RE: Reporting on health equity requires addressing measurement issues

JenniferONeill replied to jscanlan on 28 Jan 2013 at 13:24 GMT

Dear editors,

We are writing to reply to the constructive comment by Mr. Scanlan regarding our article entitled:
“PRISMA-Equity 2012 Extension: Reporting Guidelines for Systematic Reviews with a Focus on Health Equity” (Welch 2012).

We developed reporting guidelines which aim to improve the transparency and accuracy of reporting of equity-focused systematic reviews, thus allowing the reader to judge the reliability of results (Moher 2010). We identified the need for these reporting guidelines based on a systematic review of the literature, and broad web-based survey of users and authors of systematic reviews. Endorsement of reporting guidelines by journals has been shown to improve the clarity of reporting (Turner 2011). PRISMA-Equity 2012 is catalogued in the EQUATOR Network library of reporting guidelines which aims to improve the reliability, utility and impact of research (Simera et al 2010).

We thank Mr. Scanlan for his detailed and thoughtful comments about the lack of clarity regarding methods for measuring and monitoring changes in health inequity over time, including how the use of relative rates, relative differences and absolute differences can be misleading, depending on a number of characteristics, well-described in the references provided by Mr. Scanlan. We agree with Mr. Scanlan that standardization and agreement about how to measure and monitor health inequity is high-priority. In our upcoming Elaboration and Explanation document of the PRISMA-Equity 2012, we will include a discussion about the issues raised by Mr. Scanlan to describe how methods for measuring changes in health equity disagree depending on choice of measure (absolute, relative rate or relative difference), baseline prevalence and whether the outcome is a favourable or adverse outcome. We will provide illustrative examples to show these points such as the example described by Mr. Scanlan of differences in school-entry hepatitis B vaccination between different ethnic groups.

Since our aim was to improve reporting, we feel that we provided an appropriate example of how absolute and relative differences are both important when considering effects on health equity. We recognize that we were unable to describe the breadth of issues in the measurement of inequity, given that we focused on improving reporting, not developing standards for measurement.

We sincerely hope that Mr. Scanlan’s call for action will prompt further research on methods for measuring inequity and interpreting these measures, and that dissemination and uptake of our reporting guidelines will encourage authors to fully report how health inequity was measured, and the rationale for the choice of measurement methods.

Vivian Welch on behalf of the author team

Moher D, Schulz KF, Simera I, Altman DG (2010) Guidance for developers of health research reporting guidelines. PLoS Med 7: e1000217 doi:10.1371/journal.pmed.1000217.
Simera I, Moher D, Hirst A, Hoey J, Schulz KF, Altman DG. Transparent and accurate reporting increases reliability, utility, and impact of your research: reporting guidelines and the EQUATOR Network. BMC Med. 2010 Apr 26;8:24. doi: 10.1186/1741-7015-8-24.
Turner L, Moher D, Shamseer L, Weeks L, Peters J, et al. (2011) The influence of CONSORT on the quality of reporting of randomised controlled trials: an updated review. Trials 12: A47.
Welch V, Petticrew M, Tugwell P, Moher D, O'Neill J, et al. (2012) PRISMA-Equity 2012 Extension: Reporting Guidelines for Systematic Reviews with a Focus on Health Equity. PLoS Med 9(10): e1001333. doi:10.1371/journal.pmed.1001333

No competing interests declared.