ITEM 6.    Describe data collection: Was data collection planned before the index test and reference standard were performed (prospective study) or after (retrospective study)?

Example

We reviewed the charts of 251 patients who underwent dual-detector spiral CT arthrography of the knee. The study population consisted of 50 consecutive patients who underwent spiral CT arthrography and subsequent arthroscopy at our institution but not prior arthroscopy in that knee. The other 201 patients included 12 who had undergone prior knee arthroscopy and subsequent arthroscopy, 69 who were referred by physicians outside of the institution, and 120 who did not undergo arthroscopy.[1]

If authors define the study question before they identify patients and collect data, they can target the collection of study data at the enrolled patients, using special case record forms or tailored data-entry forms. Prospective, dedicated data collection has many advantages: better data control, additional checks for data integrity and consistency, and a level of clinical detail appropriate to the problem.[2] As a result, there will be fewer missing or un-interpretable data items.

Alternatively, data collection can start after patients have undergone the index test and the reference standard. Retrospective data collection often relies on chart review. Studies with retrospective data collection may reflect routine clinical practice better than a prospective study, but also may fail to identify all eligible patients or to provide data of high quality.[3]

References