Assessing Differential Attrition in Clinical Trials: Self-monitoring of Oral Anticoagulation and Type II Diabetes

Overview

Journal BMC Med Res Methodol

Publisher Biomed Central

Specialties General Medicine
Health Services

Date 2007 May 4

PMID 17474976

Citations 13

Authors

Carl Heneghan

Rafael Perera

Alison Ward A

David Fitzmaurice

Emma Meats

Paul Glasziou

Affiliations

Soon will be listed here.

Abstract

Background: Analyzing drop out rates and when they occur may give important information about the patient characteristics and trial characteristics that affect the overall uptake of an intervention.

Methods: We searched Medline and the Cochrane library from the beginning of the databases to May 2006 for published systematic reviews that compared the effects of self-monitoring (self-testing) or self-management (self-testing and self-dosage) of oral anticoagulation or self-monitored blood glucose in type 2 diabetics who were not using insulin. We assessed all study withdrawals pre-randomization and post randomization and sought information on the reasons for discontinuation of all participants.To measure the differential between groups in attrition we used the relative attrition (RA), which is equivalent to relative risk but uses attrition as the outcome (i.e. attrition in intervention group/attrition in control group). We determined the percentage drop outs for control and intervention groups and used DerSimonian and Laird random effects models to estimate a pooled relative attrition. L'abbe type plots created in R (version 2.0.2) were used to represent the difference in the relative attrition among the trials with 95% confidence areas and weights derived from the random effects model.

Results: With self-monitoring of blood glucose in type 2 diabetes, attrition ranged from 2.3% to 50.0% in the intervention groups and 0% to 40.4% in the control groups. There was no significant difference between the intervention and control, with an overall RA of 1.18 [95% CI, 0.70-2.01]. With self-monitoring of oral anticoagulation attrition ranged from 0% to 43.2% in the intervention groups and 0% to 21.4% in the control group. The RA was significantly greater in the intervention group, combined RA, 6.05 [95% CI, 2.53-14.49].

Conclusion: This paper demonstrates the use of relative attrition as a new tool in systematic review methodology which has the potential to identify patient, intervention and trial characteristics which influences attrition in trials.

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References

Welschen L, Bloemendal E, Nijpels G, Dekker J, Heine R, Stalman W . Self-monitoring of blood glucose in patients with type 2 diabetes who are not using insulin: a systematic review. Diabetes Care. 2005; 28(6):1510-7. DOI: 10.2337/diacare.28.6.1510. View

Welschen L, Bloemendal E, Nijpels G, Dekker J, Heine R, Stalman W . Self-monitoring of blood glucose in patients with type 2 diabetes mellitus who are not using insulin. Cochrane Database Syst Rev. 2005; (2):CD005060. DOI: 10.1002/14651858.CD005060.pub2. View

Tierney J, Stewart L . Investigating patient exclusion bias in meta-analysis. Int J Epidemiol. 2004; 34(1):79-87. DOI: 10.1093/ije/dyh300. View

de Sola-Morales Serra O, Elorza Ricart J . [Portable coagulometers: a systematic review of the evidence on self-management of oral anticoagulant treatment]. Med Clin (Barc). 2005; 124(9):321-5. DOI: 10.1157/13072418. View

Gadisseur A, Breukink-Engbers W, van der Meer F, van den Besselaar A, Sturk A, Rosendaal F . Comparison of the quality of oral anticoagulant therapy through patient self-management and management by specialized anticoagulation clinics in the Netherlands: a randomized clinical trial. Arch Intern Med. 2003; 163(21):2639-46. DOI: 10.1001/archinte.163.21.2639. View

White R, McCurdy S, von Marensdorff H, Woodruff Jr D, Leftgoff L . Home prothrombin time monitoring after the initiation of warfarin therapy. A randomized, prospective study. Ann Intern Med. 1989; 111(9):730-7. DOI: 10.7326/0003-4819-111-9-730. View

Gardiner C, Williams K, Mackie I, Machin S, Cohen H . Patient self-testing is a reliable and acceptable alternative to laboratory INR monitoring. Br J Haematol. 2005; 128(2):242-7. DOI: 10.1111/j.1365-2141.2004.05300.x. View

Sarol Jr J, Nicodemus Jr N, Tan K, Grava M . Self-monitoring of blood glucose as part of a multi-component therapy among non-insulin requiring type 2 diabetes patients: a meta-analysis (1966-2004). Curr Med Res Opin. 2005; 21(2):173-84. DOI: 10.1185/030079904X20286. View

Cromheecke M, Levi M, Colly L, de Mol B, Prins M, Hutten B . Oral anticoagulation self-management and management by a specialist anticoagulation clinic: a randomised cross-over comparison. Lancet. 2000; 356(9224):97-102. DOI: 10.1016/S0140-6736(00)02470-3. View

10.

Allen B, DeLong E, Feussner J . Impact of glucose self-monitoring on non-insulin-treated patients with type II diabetes mellitus. Randomized controlled trial comparing blood and urine testing. Diabetes Care. 1990; 13(10):1044-50. DOI: 10.2337/diacare.13.10.1044. View

11.

Fitzmaurice D, Murray E, McCahon D, Holder R, Raftery J, Hussain S . Self management of oral anticoagulation: randomised trial. BMJ. 2005; 331(7524):1057. PMC: 1283185. DOI: 10.1136/bmj.38618.580903.AE. View

12.

Miles P, Everett J, Murphy J, Kerr D . Comparison of blood or urine testing by patients with newly diagnosed non-insulin dependent diabetes: patient survey after randomised crossover trial. BMJ. 1997; 315(7104):348-9. PMC: 2127248. DOI: 10.1136/bmj.315.7104.348. View

13.

Schulz K, Grimes D . Sample size slippages in randomised trials: exclusions and the lost and wayward. Lancet. 2002; 359(9308):781-5. DOI: 10.1016/S0140-6736(02)07882-0. View

14.

Muchmore D, Springer J, Miller M . Self-monitoring of blood glucose in overweight type 2 diabetic patients. Acta Diabetol. 1994; 31(4):215-9. DOI: 10.1007/BF00571954. View

15.

Sunderji R, Gin K, Shalansky K, Carter C, Chambers K, Davies C . A randomized trial of patient self-managed versus physician-managed oral anticoagulation. Can J Cardiol. 2004; 20(11):1117-23. View

16.

Heneghan C, Alonso-Coello P, Garcia-Alamino J, Perera R, Meats E, Glasziou P . Self-monitoring of oral anticoagulation: a systematic review and meta-analysis. Lancet. 2006; 367(9508):404-11. DOI: 10.1016/S0140-6736(06)68139-7. View

17.

Voller H, Glatz J, Taborski U, Bernardo A, Dovifat C, Burkard G . [Background and evaluation plan of a study on self-management of anticoagulation in patients with non-valvular atrial fibrillation (SMAAF Study)]. Z Kardiol. 2000; 89(4):284-8. DOI: 10.1007/s003920050486. View

18.

Beyth R, Quinn L, Landefeld C . A multicomponent intervention to prevent major bleeding complications in older patients receiving warfarin. A randomized, controlled trial. Ann Intern Med. 2000; 133(9):687-95. DOI: 10.7326/0003-4819-133-9-200011070-00010. View

19.

Odegaard K . [Self-management in anticoagulation--a meta-analysis]. Tidsskr Nor Laegeforen. 2004; 124(22):2900-3. View

20.

Kortke H, Korfer R . International normalized ratio self-management after mechanical heart valve replacement: is an early start advantageous?. Ann Thorac Surg. 2001; 72(1):44-8. DOI: 10.1016/s0003-4975(01)02656-x. View