Systematic Review and Meta-Analysis of Social Cognitive Theory-Based Interventions on Glycemic Control in Adults with Type 2 Diabetes Mellitus
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Background: Type 2 Diabetes Mellitus (T2DM) has severe consequences for those who fail to engage in self-management activities. Insulin resistance characterizes T2DM, and often, treatment regimens are complex, requiring sustained concentration and an ability to act. Controlled glucose enhances quality and length of life, yet over 47% of T2DM experience sub-optimal glycemic control. Self-management interventions are primarily behavioral and have subjective outcomes, e.g., self-efficacy. And, commonly objective biomarkers are measured as evidence of glycemic control (i.e., glycosylated hemoglobin, HgBA1c). Identifying the mechanism of action that creates long-term glycemic control using behavioral interventions with objective measures complicates the problem for researchers, clinicians, and those living with the disease. A theory is a systematic way to identify and demonstrate connections between concepts and outcomes. The lack of a theoretical foundation creates confounding variables through the absence of trial guidance, implementation, and intervention fidelity. Theory-based behavioral interventions have been shown to improve glycemic control effectively. However, no specific theory has been identified as effective. Objective: This dissertation aims to determine the effectiveness of social cognitive theory-based interventions for adults with T2DM to enhance glycemic control. The two-and-a-half-year literature review, Chapter Two, manuscript one, identified social cognitive theory-based (SCT) as the theory most used to enhance glycemic control in adults with T2DM. And SCT trials were seen to have a greater impact on glycemic control and exhibit higher quality compared to other theories by addressing all three domains needed for behavioral change (e.g., cognitive, affective, psychomotor). Method: Chapter Three, manuscript two, outlines the methodology for determining SCT effectiveness by conducting a systematic review and meta-analysis. The goals of this dissertation were met with multiple stages of research incorporating the results of the comprehensive and extensive literature reviews. The systematic review and meta-analysis, Chapter Four; manuscript three, were compliant with scientific standards of quality set by the National Institute of Health, the International Prospective Register of Systematic Reviews, Cochrane Handbook for Systematic Reviews of Interventions, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Results: The results are presented in Chapter Four and show SCT-based interventions are effective to improve HgBA1c compared to usual care (d=0.31, 95% CI=0.19, 0.43, p< 0.000). In a moderator analysis (e.g., self-efficacy, problem-solving, social support, knowledge) and a subgroup analysis of moderators based on timeframe (e.g., short-term being < 89 days, long-term > 90 days) results show there was no significant effect on SCT interventions. Results indicate each component is not more effective than another; all SCT may be needed to enhance glycemic control in adults with T2DM. Conclusions: The rigorous scrutiny of the literature over four and a half years show SCT-based interventions are most frequently used and effective to improve glycemic control in adults living with T2DM. Moderators of SCT were not statistically significant but are clinically relevant. The results of this dissertation align with the tenants of SCT that behavior change occurs through cognitive pathways. All SCT components are needed to enhance glycemic control as each one carries a different weight. Each component is clinically important to help adults living with T2DM over the psychological barriers that accompany the disease. Therefore, a staged and reinforced approach is recommended to implement knowledge and social support of participants in the early stages of an intervention or clinical practice. As patients gain knowledge and realize how much knowledge is missing, self-efficacy may need to be reinforced. Self-efficacy may be enhanced by patients setting and meeting short-term goals during knowledge enhancement. Ongoing education and support may help patients build long-term problem-solving skills. PROSPERO ID: CRD42020147105