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Psychological impact of screening for type 2 diabetes: controlled trial and comparative study embedded in the ADDITION (Cambridge) randomised controlled trial

BMJ 2007; 335 doi: (Published 06 September 2007) Cite this as: BMJ 2007;335:486
  1. Helen C Eborall, post-doctoral research fellow1,
  2. Simon J Griffin, programme leader2,
  3. A Toby Prevost, medical statistician1,
  4. Ann-Louise Kinmonth, professor of general practice1,
  5. David P French, reader in health behaviour interventions3,
  6. Stephen Sutton, professor of behavioural science1
  1. 1General Practice and Primary Care Research Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge CB2 0SR
  2. 2Medical Research Council Epidemiology Unit, Strangeways Research Laboratory, Cambridge
  3. 3Applied Research Centre in Health and Lifestyle Interventions, Coventry University, Coventry
  1. Correspondence to: H C Eborall hce21{at}
  • Accepted 6 August 2007


Objective To quantify the psychological impact of primary care based stepwise screening for type 2 diabetes.

Design Controlled trial and comparative study embedded in a randomised controlled trial.

Setting 15 practices (10 screening, five control) in the ADDITION (Cambridge) trial in the east of England.

Participants 7380 adults (aged 40-69) in the top fourth for risk of having undiagnosed type 2 diabetes (6416 invited for screening, 964 controls).

Interventions Invited for screening for type 2 diabetes or not invited (controls), incorporating a comparative study of subgroups of screening attenders. Attenders completed questionnaires after a random blood glucose test and at 3-6 months and 12-15 months later. Controls were sent questionnaires at corresponding time points. Non-attenders were sent questionnaires at 3-6 months and 12-15 months.

Main outcome measures State anxiety (Spielberger state anxiety inventory), anxiety and depression (hospital anxiety and depression scale), worry about diabetes, and self rated health.

Results No significant differences were found between the screening and control participants at any time—for example, difference in means (95% confidence intervals) for state anxiety after the initial blood glucose test was −0.53, −2.60 to 1.54, at 3-6 months was 1.51 (−0.17 to 3.20), and at 12-15 months was 0.57, −1.11 to 2.24. After the initial test, compared with participants who screened negative, those who screened positive reported significantly poorer general health (difference in means −0.19, −0.25 to −0.13), higher state anxiety (0.93, −0.02 to 1.88), higher depression (0.32, 0.08 to 0.56), and higher worry about diabetes (0.25, 0.09 to 0.41), although effect sizes were small. Small but significant trends were found for self rated health across the screening subgroups at 3-6 months (P=0.047) and for worry about diabetes across the screen negative groups at 3-6 months and 12-15 months (P=0.001).

Conclusions Screening for type 2 diabetes has limited psychological impact on patients. Implementing a national screening programme based on the stepwise screening procedure used in the ADDITION (Cambridge) trial is unlikely to have significant consequences for patients' psychological health.

Trial registration Current Controlled Trials ISRCTN99175498.


  • We thank the participants and the practices; the Cambridge ADDITION trial coordination team, in particular Kate Williams (trial manager), Lincoln Sargeant (clinical epidemiologist), Ryan Butler (data manager), Tom Fanshawe (medical statistician), Lewis Moore, Pesheya Doubleday, Ros Barling, and Nick Wareham (principal investigator, ADDITION trial); and the Medical Research Council field epidemiology team, in particular Sandra Bovan, Liz White, Christine May-Hall, Rozi Robbins, Muriel Hood, Georgina Lewis, Kate Westgate, and Ros Stevenson (leads Suzie Hennings and Paul Roberts).

  • Contributors: SS, DPF, ATP, A-LK, and SJG conceived and designed the original protocol. All authors were involved in amending the protocol. HCE coordinated the study throughout. Data entry was carried out by Wyman Dillon Ltd, Lewis Moore, and HCE. HCE cleaned the data and ran preliminary analysis with input from Tom Fanshawe. ATP analysed the data. ADDITION trial data were supplied by Lincoln Sargeant and Kate Williams. HCE wrote the first draft of the manuscript with ATP and SS. All authors contributed to subsequent and final drafts. HCE is guarantor of the paper.

  • Funding: This study was funded by a project grant from the Wellcome trust (reference No 071200/Z/03/Z). NHS Research and Development provided support for science funding to cover the NHS costs of hosting the research. The Cambridge ADDITION trial was funded by the Wellcome trust (reference No G0000753). HCE is funded by post doctoral fellowship from the Economic and Social Research Council/Medical Research Council.

  • Competing interests: None declared.

  • Ethical approval: Ethical approval was granted by the eastern multicentre research ethics committee (reference No 02/5/54).

  • Accepted 6 August 2007
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