Efficacy of the Flexible Lifestyles Empowering Change intervention on metabolic and psychosocial outcomes in adolescents with type 1 diabetes (FLEX): a randomised controlled trial

Summary Background Adolescents with type 1 diabetes commonly have poor glycaemic control. We aimed to test the efficacy of a newly developed adaptive behavioral intervention (Flexible Lifestyles Empowering Change; FLEX) on metabolic and psychosocial outcomes in adolescents with type 1 diabetes. Methods Young people (13–16 years, type 1 diabetes duration >1 year, HbA 1c of 64–119 mmol/mol [8·0–13·0%], and without other serious medical conditions or pregnancy) from two clinical sites (Colorado and Ohio, USA) were eligible for enrolment. One caregiver was required to participate actively in the study. Adolescent participants were randomly assigned to the FLEX intervention, which used motivational interviewing and problem-solving skills training to enhance patients' self-management, or usual care control. Intervention fidelity was assessed by a behavioral psychologist with specific expertise in motivational interviewing and who was not otherwise involved in the study via audiotaped sessions. The primary outcome was measurement of glycated haemoglobin A 1c (HbA 1c ) at 18 months. Secondary outcomes included motivation and intention, problem solving skills, self-management behaviors, symptoms of depression, health related quality of life, fear of hypoglycemia, diabetes family conflict, risk factors for T1D complications (BMI, blood pressure, and plasma lipids), and hypoglycemia derived from continuous glucose monitoring (percent time below 3·0 and 3·9 mmol/l [54 and 70 mg/dl]). Intention-to-treat analyses used mixed effects models, with fixed effects including site, timepoint, intervention group, intervention by timepoint, and baseline level of primary (HbA 1c ) or secondary outcomes (α=0·05). FLEX is registered on clinicaltrials.gov , number NCT01286350 . Findings Young people recruited from May 1, 2014 to April 4, 2016 were randomly assigned to FLEX (n=130) or usual care control (n=128). Mean diabetes duration was 6·4 (SD 3·8) years, and 71% (181 out of 256) of patients used insulin pump therapy. Retention was 93%, with 241 out of 258 completing the 18-month assessment. The intervention fidelity score was 4·40 of 5·00 for motivational interviewing and 97% for session content. At 18 months, HbA 1c was not significantly different between intervention (83 [13] mmol/mol at baseline; 84 [19] mmol/mol at follow-up); and control (80 [14] mmol/mol at baseline; 82 [17] mmol/mol at follow-up); change in intervention versus control was −0·7 mmol/mol (95% CI −4·7 to 3·4, p=0·75). The intervention was associated with improved scores for motivation (p=0·011), problem solving (p=0·024), diabetes self-management profile (p=0·013), youth report of overall quality of life (p=0·0089), selected domains related to fear of hypoglycaemia (p=0·036 for youth's helplessness or worry; p=0·0051 for parent's efforts to maintain high blood glucose), parent report of diabetes family conflict (p=0·0001), total cholesterol (p=0·038), and diastolic blood pressure (p=0·015). A total of 54 serious adverse events were identified; 34 of these were diabetes-related, including low blood glucose requiring assistance (n=3) and high blood glucose with diabetic ketoacidosis and emergency response (n=25). Interpretation The FLEX intervention did not significantly change HbA 1c among these adolescents with elevated HbA 1c , but did positively affect several psychosocial outcomes over 18 months. Further analyses will provide information regarding drivers of positive response to the intervention and will point to future directions for improvement in the approach. Funding National Institutes of Health and National Institute of Diabetes Digestive Diseases and Kidney and the Helmsley Charitable Trust.