ABSTRACT
AIMS: To provide a systematic review and meta-analysis of recent evidence on the effectiveness of lifestyle-based weight loss interventions for adults with type 2 diabetes. METHODS: A search of the literature from January 2003 to July 2013 was conducted (PubMed, Embase, CINAHL and Web of Science). The studies considered eligible were randomized controlled trials evaluating weight loss interventions (diet and physical activity, with or without behavioural strategies) of ≥12 weeks duration, compared with usual care or another comparison intervention. Ten studies were included for review. Some heterogeneity was present in the sample, therefore, random-effects models were used to calculate pooled effects. RESULTS: Intervention duration ranged from 16 weeks to 9 years, with all but one delivered via individual or group face-to-face sessions. From six studies comparing lifestyle intervention with usual care the pooled effect on weight (n = 5795) was -3.33 kg [95% confidence interval (CI) -5.06, -1.60 kg], and on glycated haemoglobin (HbA1c; n = 5784) was -0.29% (95% CI -0.61, 0.03%), with both attenuated in sensitivity analyses. The pooled within-group effect on weight (n = 3063) from all 10 lifestyle intervention groups was -5.33 kg (95% CI -7.33, -3.34 kg), also attenuated in sensitivity analyses. None of the participant or intervention characteristics examined explained the heterogeneity. Only one study assessed whether intervention effects were maintained after the end of the intervention. CONCLUSIONS: Lifestyle-based weight loss intervention trials in type 2 diabetes achieve, on average, modest reductions in weight and HbA1c levels, but results were heavily influenced by one trial. Evidence-based approaches for improving the effectiveness of lifestyle-based interventions in type 2 diabetes are needed, along with future studies reporting on maintenance and cost-effectiveness.
Subject(s)
Diabetes Mellitus, Type 2/complications , Diet, Diabetic , Diet, Reducing , Evidence-Based Medicine , Life Style , Motor Activity , Obesity/therapy , Behavior Therapy , Combined Modality Therapy , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/diet therapy , Diabetes Mellitus, Type 2/therapy , Glycated Hemoglobin/analysis , Humans , Hyperglycemia/prevention & control , Obesity/complications , Obesity/diet therapy , Patient Education as Topic , Randomized Controlled Trials as Topic , Weight LossABSTRACT
Obesity has been associated with poor health outcomes in breast cancer survivors. Thus, weight loss is recommended for overweight and obese survivors. We systematically reviewed studies (published up to July 2013) that evaluated behaviourally based, weight loss interventions in women with breast cancer exclusively. Completed randomized trials, single-arm trials and ongoing trials were reviewed. Within-group and between-group differences for weight loss were extracted, as was data on secondary outcomes, i.e. clinical biomarkers, patient-reported outcomes, adverse events. Ten completed randomized trials, four single-arm trials and five ongoing trials were identified. Statistically significant within-group weight loss was observed over periods of 2 to 18 months in 13 of the 14 trials, with six randomized and two single-arm trials observing mean weight loss ≥5%. Clinical biomarkers, psychosocial and patient-reported outcomes were measured in a small number of studies. No serious adverse events were reported. Only two trials assessed maintenance of intervention effects after the end-of-intervention and none reported on cost-effectiveness. The studies included in this review suggest that weight loss is feasible to achieve and is safe in women following treatment for breast cancer. Future studies should assess (and be powered for) a range of biomarker and patient-reported outcomes, and be designed to inform translation into practice.
