Reliability of administrative data to identify sexually transmitted infections for population health: a systematic review

Methods

To examine the existing literature on the validity of using administrative data to identify STI cases, we conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. We performed a comprehensive search of the literature using the MEDLINE and Scopus databases for peer-reviewed articles published before February 2018. We limited the scope of our review to chlamydia, gonorrhoea and syphilis, as these are the STIs that constitute the highest reportable morbidity for local health departments.

Articles were identified using search terms consisting of search strings as well as Medical Subject Heading (MeSH) terms associated with the key words. We used STI-related search terms including ‘syphilis’, ‘gonorrhoea’, ‘chlamydia’, ‘pelvic inflammatory disease’, ‘sexually transmitted disease’ and those related to administrative codes such as ‘international classification of diseases’, ‘administrative codes’, ‘ICD’, ‘diagnostic codes’, ‘diagnosis, classification’, ‘international classification of diseases’, ‘ICD code’, together with terms intended to identify validation studies: ‘validation studies’, ‘reliability’ and ‘validity’. Pelvic inflammatory disease (PID) was included as previous literature indicates that 33%–50% of all PID cases are due to either Chlamydia trachomatis or Neisseria gonorrhoeae.13 14

Only empirical publications appearing in peer-reviewed English language journals were included. As such, we excluded articles classified as letters to the editor, policy briefs, perspectives, commentaries, summaries of future research plans, as well as grey literature. Additionally, articles without abstracts were also excluded.

Article identification and selection followed the process outlined in figure 1. We used Covidence (Melbourne, Victoria, Australia), a web-based tool developed for systematic reviews by Cochrane, to facilitate article selection and review.

In the first step, articles were reviewed with a focus on title and abstract. We eliminated articles that did not focus on STIs or did not validate STI administrative data as a component of the research. This included validation studies focused on conditions or diseases other than STIs. Articles were included if they focused on any combination or all of the STIs of interest, or on PID, and were validation studies focused on diagnostic testing or administrative codes.

Screened articles were then subjected to a second review which focused on including only validation studies examining the use of either ICD, Ninth Revision, Clinical Modification (ICD-9-CM) or ICD, 1oth Revision, Clinical Modification (ICD-10-CM) codes to identify diagnosis of chlamydia, gonorrhoea, syphilis or PID. Other forms of administrative data, such as pharmacy claims, to identify cases were not considered because the target STIs of interest are often treated with common antibiotics such as azithromycin which is also used to treat a number of other bacterial infections. Moreover, studies that focused on the validation of specific laboratory assessments such as PCR assays for diagnosing chlamydia were also excluded.

Two reviewers (SR and YH) reviewed each article to determine inclusion with conflicts in judgement reconciled by consensus. Finally, in order to be exhaustive, we used a snowball technique whereby we reviewed all references found in the bibliographies of included articles.

The final set of articles included for review met the following criteria: (1) the study included syphilis, chlamydia or gonorrhoea; (2) assessed and listed ICD-9-CM or ICD-10-CM codes and (3) measured accuracy, sensitivity, specificity, PPV and/or negative predictive value for ICD codes related to any of the three STIs. With the selected articles, references from each article were examined to identify other relevant articles.

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