Influence of Disease Knowledge on the Metabolic Control of Diabetes Mellitus: A Cross-Sectional Study

Diabetes mellitus is a prevalent disease in the Portuguese population and is associated with significant morbidity and mortality. Its proper therapeutic management is multifactorial, with lifestyle habits having a major impact. Studies show that poorer metabolic control is associated with deficient knowledge related to diabetes, lower self-efficacy, and limited patient empowerment. The aim of this study was to characterize diabetic patients' knowledge about their disease using the Diabetes Knowledge Test (DKT) and to assess the potential correlation between disease knowledge and metabolic control.

A cross-sectional study was conducted involving a convenience sample of diabetics followed in four primary care units in Braga, Portugal. The sample was divided into two groups: insulin-treated (IT) and non-insulin-treated (NT).

Each participant was given the DKT. Frequency measures were used to describe the sociodemographic characteristics and clinical parameters. For association between categorical variables, the Fisher's test and chi-square test were used. To compare the distribution of the response variable (metabolic control represented by glycated hemoglobin (HbA1C) values) between IT and NT, the Mann-Whitney test was used. For association between nominal qualitative variables, the chi-square test was employed. The statistical significance level used in the tests was 5% (p<0.05).

A total of 99 responses were obtained, with an average age of 65.5 years. Most of the respondents were male, had a low education level, were overweight, and had type 2 diabetes diagnosed 10 or more years ago, with an average HbA1C value of 6.83%. The average performance obtained by the DKT scale revealed medium levels of knowledge (IT and NT). Both groups displayed a medium level of knowledge (59% for NT and 62.5% for IT), without statistically significant difference. There was a statistical difference in metabolic control between IT and NT (Mann-Whitney test, p<0.05). Regarding the degree of knowledge of the disease (by DKT results), there was no statistically significant association, using the Fisher's test (p=0.20), between the two groups. In NT, there was no statistically significant association between metabolic control and the degree of knowledge (Fisher's test, p=0.69). There was an association between metabolic control and the duration of the disease (Fisher's test, p=0.029, odds ratio 3.83) in NT, as in IT (p=0.025). However, there was not a proven association between metabolic control and the degree of knowledge in IT (Fisher's test, p=0.62).

This study provides a comprehensive analysis of the characteristics of patients with diabetes and the factors affecting both metabolic control and disease knowledge. Although general knowledge of diabetes was "medium" for most patients, this level of knowledge may not be sufficient to ensure good self-care, especially in IT and those with a longer duration of disease. A longer duration of diagnosis was associated with poorer metabolic control, which may be related to the natural progression of diabetes and the challenges in maintaining adequate control over time. This finding highlights the need for continuous and personalized strategies for managing the disease as it progresses. Furthermore, these results emphasize the need for public health policies that promote enhanced diabetes education, aiming to empower patients to manage their condition more effectively.