UCL logo

UCL Discovery

UCL home » Library Services » Electronic resources » UCL Discovery

Representativeness and optimal use of body mass index (BMI) in the UK Clinical Practice Research Datalink (CPRD)

Bhaskaran, K; Forbes, HJ; Douglas, I; Leon, DA; Smeeth, L; (2013) Representativeness and optimal use of body mass index (BMI) in the UK Clinical Practice Research Datalink (CPRD). BMJ Open , 3 (9) , Article e003389. 10.1136/bmjopen-2013-003389. Green open access

[img]
Preview
PDF
BMJ Open-2013-Bhaskaran-.pdf
Available under License : See the attached licence file.

Download (1MB)

Abstract

Objectives: To assess the completeness and representativeness of body mass index (BMI) data in the Clinical Practice Research Datalink (CPRD), and determine an optimal strategy for their use. Design: Descriptive study. Setting: Electronic healthcare records from primary care. Participants: A million patient random sample from the UK CPRD primary care database, aged ≥16 years. Primary and secondary outcome measures: BMI completeness in CPRD was evaluated by age, sex and calendar period. CPRD-based summary BMI statistics for each calendar year (2003–2010) were age-standardised and sex-standardised and compared with equivalent statistics from the Health Survey for England (HSE). Results: BMI completeness increased over calendar time from 37% in 1990–1994 to 77% in 2005–2011, was higher among females and increased with age. When BMI at specific time points was assigned based on the most recent record, calendar–year-specific mean BMI statistics underestimated equivalent HSE statistics by 0.75–1.1 kg/m2. Restriction to those with a recent (≤3 years) BMI resulted in mean BMI estimates closer to HSE (≤0.28 kg/m2 underestimation), but excluded up to 47% of patients. An alternative strategy of imputing up-to-date BMI based on modelled changes in BMI over time since the last available record also led to mean BMI estimates that were close to HSE (≤0.37 kg/m2 underestimation). Conclusions: Completeness of BMI in CPRD increased over time and varied by age and sex. At a given point in time, a large proportion of the most recent BMIs are unlikely to reflect current BMI; consequent BMI misclassification might be reduced by employing model-based imputation of current BMI.

Type: Article
Title: Representativeness and optimal use of body mass index (BMI) in the UK Clinical Practice Research Datalink (CPRD)
Open access status: An open access version is available from UCL Discovery
DOI: 10.1136/bmjopen-2013-003389
Publisher version: http://dx.doi.org/10.1136/bmjopen-2013-003389
Language: English
Additional information: This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/3.0/
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Pop Health Sciences > Institute for Global Health
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Pop Health Sciences > Institute for Global Health > Infection and Population Health
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Pop Health Sciences > Institute of Cardiovascular Science
URI: http://discovery.ucl.ac.uk/id/eprint/1449658
Downloads since deposit
181Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item