Meta-analysis of individual patient data in randomised trials of self-monitoring of blood glucose in people with non-insulin treated type 2 diabetes.

AJ Farmer, R Perera, A Ward, C Heneghan, J Oke, AH Barnett, C Chambers, B Guerci, Vivien Coates, U Schwedes, S O'Malley

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Abstract

AbstractObjective To assess the effectiveness of self monitoring blood glucoselevels in people with non-insulin treated type 2 diabetes compared withclinical management without self monitoring, and to explore the effectsin specific patient groups.Design Meta-analysis based on individual participant data.Data sources Medline, Embase, and a recent systematic review of trialson self monitoring of blood glucose. Chief investigators of trials publishedsince 2000 were approached for additional information and individualpatient data.Inclusion criteria Randomised controlled trials in patients withnon-insulin treated type 2 diabetes comparing an intervention using selfmonitoring of blood glucose with clinical management not using selfmonitoring. Trials published from 2000 with at least 80 participants wereincluded.Data collection Individual patient data were collected from electronicfiles and checked for integrity.Analysis All randomised participants were analysed using the intentionto treat principle. A random effects model of complete cases was usedto assess efficacy, a sensitivity analysis comprised imputed data, andprespecified subgroup analyses were carried out for age, sex, previoususe of self monitoring, duration of diabetes, and levels of glycatedhaemoglobin (HbA1c) at baseline.Results 2552 patients were randomised in the six included trials. Amean reduction in HbA1c level of −2.7 mmol/mol (95% confidence interval−3.9 to −1.6; 0.25%) was observed for those using self monitoring ofblood glucose levels compared with no self monitoring at six months.The mean reduction in HbA1c level between groups was 2.0 mmol/mol(3.2 to 0.8; 0.25%) at three months (five trials) and 2.5 mmol/mol (4.1to 0.9; 0.35%) at 12 months (three trials). These estimates wereunchanged after imputing missing data, and estimates of effect in trialswith higher loss to follow-up or a possibility of co-intervention comparedwith those with lower loss to follow-up and no co-intervention did notdiffer significantly (P=0.21). The difference in HbA1c levels betweengroups was consistent across age, baseline HbA1c level, sex, and durationof diabetes, although the numbers of older and younger people andthose with HbA1c levels >86 mmol/mol (10%) were insufficient forinterpretation. No changes occurred in systolic blood pressure (−0.2 mmHg, 95% confidence interval −1.4 to 1.0), diastolic blood pressure (−0.1mm Hg, −0.9 to 0.6), or total cholesterol level (−0.1 mol/L, 95%confidence interval −0.2 to 0.1).Conclusions Evidence from this meta-analysis of individual patient datawas not convincing for a clinically meaningful effect of clinicalmanagement of non-insulin treated type 2 diabetes by self monitoringof blood glucose levels compared with management without selfmonitoring, although the difference in HbA1c level between groups wasCorrespondence to: A Farmer andrew.farmer@phc.ox.ac.ukExtra material supplied by the author (see http://www.bmj.com/content/344/bmj.e486?tab=related#webextra)Search termsFurther details of study characteristicsNo commercial
Original languageEnglish
Pages (from-to)1-11
JournalBRITISH MEDICAL JOURNAL
Volume344
DOIs
Publication statusPublished - 27 Feb 2012

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