A 12-month intensive supervised exercise intervention and counselling reduces HbA1c, blood pressure and other modifiable cardiovascular risk factors in people with type 2 diabetes
- Correspondence to Gail D'Eramo Melkus
726 Broadway, 10th Floor, New York, NY 10003, USA;
Implications for nursing practice and research
▪ Physical activity (PA), exercise performance and counselling require demonstration, supervision and support similar to other self-management behaviour for day-to-day chronic illness management.
▪ Structured individual PA counselling should acknowledge the benefit and importance of occupational, home, leisure time and commuting PA.
▪ Healthcare providers and settings should consider partnering with fitness centres/exercise facilities for structured, supervised exercise interventions for chronic illness prevention and management.
▪ Further research is needed to develop and utilise more objective measures of PA than self-report accounts. Programmable pedometers or accelerometers for non-supervised PA, in combination with supervised PA training, may be options for further research to more accurately account for total PA.
▪ Electronic PA metres should be studied for non-supervised PA in combination with structured individual exercise counselling to determine feasibility and efficacy.
Diabetes and its related complications continue to be a global health concern. More than 285 million individuals worldwide have diabetes; a number that is growing due to increasing rates of sedentary lifestyle, fast-food consumption and obesity. The purpose of the study was to test the effect of an intensive, structured, supervised exercise programme plus individual counselling intervention on metabolic control (haemoglobin A1c (HbA1c)) and cardiovascular (CV) risk factors in sedentary adults with type 2 diabetes. Participants were from 22 outpatient diabetes clinics throughout Italy and were followed for 12 months.
A total of 606 patients were enrolled and randomly assigned to an intervention of intensive structured supervised exercise plus individual exercise counselling (experimental group) or structured individual exercise counselling, alone, as part of standard diabetes care (control group). Random assignment was stratified by diabetes centre, and within each centre, based on age (<60 or ≥60 years) and type of diabetes treatment (diet and oral agents vs insulin). Standard care was based on established clinical guidelines for optimal blood glucose and blood pressure levels and body weight parameters, which included use of glucose, lipid and blood pressure medications. Participants in the experimental group received exercise training at metabolic fitness centres for 150 min/week that consisted of two sessions of aerobic and resistance training. Aerobic exercise was performed on equipment such as the treadmill, elliptical, cycle ergometer and stepper at maximal oxygen consumption. Multiple metabolic, anthropometric, PA measures (including patient self-report of leisure, work and commuting PA) were collected in addition to medication usage and adjustment at baseline and 12 months. The primary outcome was HbA1c, and secondary outcomes were blood glucose, total and low-density lipoprotein (LDL) lipids, use of blood pressure lowering medications and global coronary heart disease 10-year risk (calculated based on the aforementioned physiological indices obtained). Cardiorespiratory fitness was also measured at baseline and 12 months. Descriptive statistics were used to describe the study sample and baseline measures; inferential statistics such as t tests were used to determine between-group differences in outcome measures baseline to 12 months and regression analyses were used to examine change over time in medications, predictors of change in HbA1c and likelihood to achieve established guideline physiologic targets.
Results showed that there were no significant differences in study variables of interest between the experimental and control groups at baseline. Study attrition resulted in 288 participants in the experimental group (115 female, 173 male) and 275 participants (119 female, 156 male) in the control group completing the study. Although both groups had noted increases in self-reported conditioning PA (aerobic), which was greatest at 4 months, the experimental group had significantly greater energy expenditure from conditioning PA than did the control group. This resulted in significantly greater improvements in cardiorespiratory and fitness outcomes in the experimental than control group. At 12 months, HbA1c was significantly reduced in the experimental group. Predictors of reduction in HbA1c were waist circumference, insulin resistance, age, male gender and higher baseline HbA1c. The experimental group also had significantly greater improvements in coronary heart disease risk factors. The control group had significant decreases in fasting blood glucose, waist circumference, blood pressure, total cholesterol and LDL cholesterol levels. A significantly greater percentage of participants in the experimental group reduced medication number and/or dosage. At 12 months, the chance of reaching established target physiologic goals was significantly greater for the experimental than control group.
This study was conducted using a longitudinal randomised controlled design over 12 months to test the effect of an experimental intervention compared with a control condition. The rigorous block randomisation of 22 diabetes centres and stratification of 606 sedentary adults with type 2 diabetes within each of the centres increased the validity of the study findings and applicability to other groups of adults with type 2 diabetes. Careful attention was given to the study intervention in which exercise training was structured and supervised, and exercise load was accounted for and measured. The structured individual exercise training component, as part of standard care, was received by both groups. Significant improvements in metabolic, CV and cardiorespiratory parameters observed in the experimental group are consistent with previous studies.1 2 It is well established that aerobic exercise and PA will decrease insulin resistance, HbA1c, blood pressure and lipid levels in persons with type 2 diabetes who are often obese and sedentary.
A unique contribution of the study is the structured individual exercise counselling as a component of care, as recommended by established clinical guidelines of the International Diabetes Federation and the American Diabetes Association.3 4 With this component of care, the control group also had significant early improvement in self-reported PA and HbA1c and significant decreases in certain metabolic parameters at 12 months, of particular importance, blood pressure and LDL cholesterol. In countries without a national or regional healthcare payment system, resource constraints, particularly in primary care, make the translation of the exercise counselling component difficult. However, the findings suggest the importance of providing a minimal intervention of structured exercise counselling in standard care. Ultimately, the partnering of healthcare settings – such as the diabetes clinics in this study – with fitness/exercise centres, where structured supervised exercise is offered, provides opportunity for improving the metabolic and CV health outcomes of sedentary individuals with type 2 diabetes. Policy consideration should be given to this exercise model of partnered care for diabetes and CV risk reduction, akin to that for cardiac rehabilitation.