Is omission of free text records a possible source of data loss and bias in Clinical Practice Research Datalink studies? A case-control study.

ABSTRACT:

Objectives

To estimate data loss and bias in studies of Clinical Practice Research Datalink (CPRD) data that restrict analyses to Read codes, omitting anything recorded as text.

Design

Matched case-control study.

Setting

Patients contributing data to the CPRD.

Participants

4915 bladder and 3635 pancreatic, cancer cases diagnosed between 1 January 2000 and 31 December 2009, matched on age, sex and general practitioner practice to up to 5 controls (bladder: n=21 718; pancreas: n=16 459). The analysis period was the year before cancer diagnosis.

Primary and secondary outcome measures

Frequency of haematuria, jaundice and abdominal pain, grouped by recording style: Read code or text-only (ie, hidden text). The association between recording style and case-con

SUBMITTER: Price SJ 

PROVIDER: S-EPMC4874123 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature