Diabetes is one of the leading causes of sickness, decreased quality of life (QoL), and deaths worldwide [1]. It is also among the top 10 causes of death globally [2, 3]. Besides, diabetes is a chronic noncommunicable disease (NCD) that occurs when the pancreas produces insufficient insulin (the hormone that regulates the body’s blood sugar level) or the body cannot effectively utilize the insulin produced [4]. Thus, diabetic patients usually take insulin daily to help absorb food nutrients into their system [5]. Globally, there were about 476 million diabetes cases, of which the incidence was about 22.9 million in 2017 [6]. Accordingly, over 1.37 million people died from the disease and its complications, with over 67.9 million disability-adjusted life years (DALYs) in 2017 [6]. The presence of diabetes exposes an individual to a 2-3-fold risk of all causes of death among adults [4]. Moreover, diabetes and cardiovascular diseases (CVD), respiratory diseases, and cancers account for over 80% of premature deaths from NCDs globally [7, 8]. Unfortunately, research shows that the condition will rise to over 693 million cases by 2045 if adequate measures, including efforts to ensure adequate self-management practices and medication adherence, are not implemented [9].
Patients with diabetes experience worse QoL than those without chronic diseases [10–12]. The QoL (physical and social functioning and perceived physical and mental well-being) of diabetic patients are mostly affected due to the management process and the need to adjust to diabetes management demands [7, 13, 14]. Thus, diabetic patients must consciously balance insulin intake and other management interventions [15]. Moreover, the psychosocial burden of living with diabetes usually affects the self-care behaviour, medication adherence, and QoL of diabetic patients [16]. The main target in diabetes care is maintaining blood glucose levels in a healthy range to avoid long-term diabetes complications through adhering to medications and appropriate self-management [17]. However, studies show low levels of medication adherence [18], poor self-management practices [19], and poor quality of life among diabetic patients [20]. Moreover, it seems there is a dearth of information on the most effective method of improving medication adherence, appropriate self-management practices, and QoL among diabetes patients [16].
Studies employed self-determination theory- (SDT-) based interventions to improve medication adherence, self-management practices, and QoL of diabetic patients [21–24]. The theory consists of three psychological needs, relatedness, competence, and autonomy, for optimal functioning [25]. Autonomy consists of diabetic patients’ experiences and perceptions of control and self-initiation in line with their idea of self [26]. Additionally, competence develops from the need to be effective in diabetes management practices and the praise or appreciation of such excellence. Also, relatedness involves the need to “experience love and care as well as to express love and care towards others” [27].
Besides, the SDT improved the quality of life of diabetes patients in Norway [28]. Also, Raaijmakers et al. [29] found that self-determination regarding type 2 diabetes care contributed to improved QoL. Moreover, the SDT improved physical activities among diabetic patients in France [30] and Uganda [31]. Although studies have linked some constructs of the SDT and QoL of adults with diabetes, the effectiveness of SDT in improving the QoL and self-management practices of adult diabetic patients is not pronounced in the literature. This scoping review examined available evidence on the link between SDT and QoL of adults with diabetes.
This scoping review was conducted following the six-stage framework by Arksey and O’Malley [32]. The framework was adopted because it helps to assess the literature to examine what has been done and identify the gaps in knowledge that need attention [33]. Arksey and O’Malley [32] suggest that the following stages should be followed in conducting a scoping review: (1) identifying and stating the research questions; (2) identifying relevant studies; (3) study selection; (4) data collection; (5) data summary and synthesis of results; and (6) consultation.
In the first stage, we identified and drafted the research questions to guide the study: (1) How effective is SDT in improving diabetes self-management? (2) How effective is SDT in improving treatment adherence? and (3) How effective is SDT in improving the QoL of adult diabetic patients?
Two authors (PO and HKK) conducted a preliminary literature search on the topic to set the inclusion and exclusion criteria. Furthermore, we expanded and refined our search strategy with expert help (an academic librarian at the University of Cape Coast). In addition, we conducted a vigorous literature review of published articles in four electronic databases (PubMed, JSTOR, Central, and ScienceDirect). We expanded the search via hand search to include other unpublished sources. The search strategy included literature from January 2011 to October 2021 using key search words and Boolean logic. Also, a free web-based search was conducted to retrieve other relevant materials. Also, Google Scholar and Z-library were searched for additional records. Furthermore, reference lists of eligible records were checked for other relevant articles.
The final search was completed on October 28, 2021. Titles and abstracts of studies retrieved were read, and only studies relevant to the study were considered. Six keywords were used in the search strategy: (“Self-determination Theory” OR “diabetes” OR “Application of Self-determination Theory” OR “QoL” OR “Diabetes self-management” OR “Diabetes medication adherence) AND (“Adults” OR “grownups” OR “people aged 18-75 years” OR “grown people”).
Studies were included if conducted among adult diabetic patients (type 1, type 2, and gestational diabetes), aged 18-75 years, measured at least one SDT-based motivational construct, and published online between January 2011 and October 2021 (with no limit concerning the start date). Also, the authors must have explicitly mentioned SDT as the framework for a study to be included.
We excluded studies that did not specify the study population and those that were not published in English. Additionally, nonprimary studies (systematic reviews and scoping reviews) and studies that used SDT-based measures but employed motivational interviewing as their guiding framework with no reference to SDT were excluded.
We used the eligibility criteria of the current study to scan the titles and appraise the abstracts of the identified literature for full-text review. We further scanned and manually screened the references of all included literature to add relevant studies to our review. Two of the current study’s authors (PO and HKK) did the full-text review independently. The authors later met, reconciled the differences, and agreed on the included studies. We then developed a data extraction sheet with the following categories: author, year of publication, study title, country, population, study design, sample size, sampling strategy, and summary of findings (see Table 1 in the Appendix). Three of the study’s authors (PO, HKK, and JOS) extracted the data independently. They later settled the differences to obtain a final result for the study. We involved third (EWA) and fourth (PYAA) reviewers to settle differences where there was disagreement in the findings of the three authors. One of the authors (PO) drafted the final extracted table (Results). All the authors read through the final draft results and ensured the findings reflected the agreed results. We finally carried out a thematic analysis and synthesis and presented the results. Additional consultations were made with subject experts to enhance the review. We used the PRISMA flow diagram to keep records and also screen the identified records (see Figure 1).