Glycemic Control and Quality of Life Among People with Type 1 Diabetes: Relationships with Insulin Therapy and Carbohydrate Counting

<b>Background/Objectives</b>: Diabetes mellitus has physical, psychological and behavioral implications related to glycemic control and quality of life. Our aims were to evaluate glycemic control and disease-related quality of life among adults with type 1 diabetes mellitus and to study their relationships with sociodemographic, clinical and anthropometric characteristics. <b>Methods</b>: Eighty-five participants (49.4% females, mean age 36 years, mean BMI 25.3 kg/m²) attending endocrinology and/or nutrition consultations at ULS São João (Porto, Portugal) were assessed regarding quality of life (Diabetes Health Profile) and social desirability (Marlowe-Crowne's scale). Anthropometric (weight and height), biochemical (A1c) and metabolic control data (time at glycemic target) were collected, as well as information on type and duration of insulin therapy, carbohydrate counting, use of mobile applications for carbohydrate counting and perceived health status. <b>Results</b>: Older patients had higher BMI (r = 0.227, <i>p</i> = 0.037) and worse quality of life in the 'barriers to activity' domain (r = 0.290, <i>p</i> = 0.007). In the multivariate analysis, sociodemographic, clinical and quality of life characteristics significantly explained A1c (<i>p</i> = 0.046, η²_p = 0.271) and perceived health status (<i>p</i> = 0.012, η²_p = 0.313). Higher eating self-efficacy significantly explained better perceived health status (<i>p</i> = 0.006, η²_p = 0.105), but no variable independently had a significant effect on glycemic control. <b>Conclusions</b>: Glycemic control results from the interaction between various clinical features that must be considered in personalized approaches. Eating self-efficacy significantly explained perceived health status, and may represent a potential target for intervention among people with type 1 diabetes mellitus.