We showed how diabetes knowledge plays a key role in self-care behavior. Our study found that, among all the self-care behaviors evaluated, physical activity mediated the association between diabetes knowledge and glycemic control in a low-income population of PwD from a large urban area. Both SES and level of education were directly associated with diabetes knowledge, but education showed a stronger impact. To the best of our knowledge, this is the first study that elucidates the pathways between diabetes knowledge and glycemic control in low-income primary care PwD.
The present study is in line with previous studies about the benefit of self-care behaviors, particularly physical activity, and provides additional information on the causal path. This study also shows the relevance of diabetes knowledge and self-care behavior in PwD. The lack of health-related knowledge and poor performance of diabetes self-care habits could partially explain the heavier diabetes burden in populations with social lag indicators. Previously, diabetes was associated with worse prognoses in Mexico than in high-income countries [[30, 31]] which made this research obligatory. For mediation analysis, we used one of the two available approaches: the Sobel test [] and bootstrapping []. Although the Sobel test has been widely used since 1982, bootstrapping has been strongly recommended in recent years. Hence, we chose bootstrapping for our mediation analysis [].
Health literacy involves the patient’s capacity to obtain, process, and understand basic health information and services needed to make appropriate decisions []. Health literacy is independently related to disease knowledge, and PwD and limited health literacy have less understanding of their disease and experience more negative outcomes than individuals with higher literacy and more knowledge [[17, 36]]. Then, to perform self-care activities, it is essential for PwD to have basic diabetes knowledge, which is usually associated with self-management behavior []. Structured therapeutic education in diabetes can determine sustained improvement and maintenance of treatment goals, lower incidence rates of all-cause mortality, and reduce first microvascular and macrovascular outcomes incidence. Therefore, educational strategies are crucial to promote empowerment in diabetes [[38, 39]].
In this study, we described a strong association of diabetes knowledge with all self-care activities evaluated, which highlights the role of diabetes knowledge in the performance of self-care activities. Eyüboğlu E, Schulz PJ et al [] did not find an interaction between diabetes knowledge and health literacy with the frequency of self-care behaviors. A distinctive feature and strength of our study was that it included a large sample of patients with low socioeconomic and educational level, in whom the burden of having poor diabetes knowledge could be more significant than in other populations. Self-care depends on the knowledge patients have about diabetes, but this knowledge alone cannot guarantee patient’s self-care practicing.
An important finding was the elucidation of socioeconomic factors on diabetes knowledge. Both factors evaluated, SES and education level, played a major role in diabetes knowledge, particularly education. This finding suggests there is a causative role of socioeconomic factors in the epidemic of complications of diabetes mellitus in underdeveloped countries. Poverty influences the development of type 2 diabetes and complications [[41, 42]]. Education and socioeconomic levels are associated with the activation of self-care management in chronic diseases []. These two social determinants could partially influence the poor performance in self-care habits, through the potential contribution and mediating effect of poor diabetes knowledge, which indicates a link between social determinants of health and diabetes self-management. Moreover, socioeconomic status was directly associated with glucose testing, which identifies the restriction PwD and low SES have to execute this behavior. These findings reiterate why health care professionals need to consider their patients’ socioeconomic status when implementing diabetes self-care management and education programs.
One strength of this study is that it included a validated tool for diabetes knowledge (SKILLD), which was designed for vulnerable populations [[22, 23]]. We observed that most patients scored low on this scale, even though PwD and long-term diabetes diagnosis were enrolled, which indicates the need for increasing diabetes education in healthcare programs. The study participants were beneficiaries of Seguro Popular in Mexico City, which attends to the largest number of primary care outpatients in Mexico []. Therefore, our results were obtained from real-world data among a representative population from a low-income subset of patients from one of the largest urban areas in the world, which is home to more than 20 million people in 1,450 km2.
Although our results are novel and potentially useful in the context of diabetes mellitus treatment in low-income countries, our study has several limitations. First, this is a cross-sectional epidemiological study, so we are not able to conclude causality. However, as any other epidemiological study, it is a hypothesis generator, and examines the relevance of education on diabetes knowledge to improve glycemic control. Second, the sample size may seem small in comparison with other diabetes studies. However, our study included a large number of participating health centers in an unprecedented manner. Third, although this study was conducted in Mexico City, a megalopolis, our findings may not be representative of other urban areas across the world. Nevertheless, the study highlights the need to consider social determinants of health and diabetes knowledge across populations that surely share similarities with our sample. Fourth, the SKILLD scale does not have a widespread use among studies that measure diabetes knowledge. Moreover, from our perspective, the traditional tools used for this purpose are difficult to understand for populations with educational lag; hence we decided to administer SKILLD, which has been tested and validated in populations similar to ours. Fifth, despite adjusting for potential confounding factors in our analysis, we did not assess for other factors that may influence glycemic control and self-care behaviors, such as pharmacological treatments, mental disorders, barriers to self-care, etc. Adverse diabetes outcomes are complex and multicausal and involve biological, individual, and social factors. In this work, we try to reinforce the relevance of some of them; we recognize the difficulty of including all the factors involved in a study of this nature.