Effects of educational technologies on the prevention and treatment of diabetic ulcers: A systematic review and meta-analysis

Objective: to analyze the effects of educational technologies in the prevention and treatment of diabetic ulcers. Method: a systematic review conducted in seven databases, a bibliographic index, an electronic library and the Gray Literature. The sample consisted of 11 randomized controlled clinical trials. The synthesis of the results was descriptive and through meta-analysis. Results: the predominant educational technologies were training sessions and verbal guidelines, with soft-hard technologies standing out. When compared to usual care, the educational technologies presented a protective factor to prevent the incidence of diabetic ulcers (RR=0.40; 95% CI=0.18-0.90; p=0.03) and the certainty of the evidence assessment was low. The educational technologies also had a protective factor to prevent the incidence of lower limb amputations (RR=0.53; 95% CI=0.31-0.90; p=0.02) and certainty of the evidence was very low. Conclusion: soft-hard educational technologies such as structured verbal guidelines, educational games, lectures, theoretical-practical training sessions, educational videos, folders, serial albums and playful drawings, and hard technologies such as therapeutic footwear, insoles, infrared digital thermometer, foot care kits, Telemedicine app and mobile phone use, were effective for the prevention and treatment of diabetic ulcers, although more robust studies are required.


Introduction
Diabetic ulcers are a health problem resulting from chronic complications of diabetes mellitus, such as peripheral neuropathy and peripheral arterial disease.
Peripheral neuropathy causes protective sensitivity loss, foot deformity, joint mobility limitation and abnormal biomechanical load on the feet, leading to the formation of calluses, subcutaneous hemorrhage and ulceration. Usually caused by atherosclerosis, peripheral artery disease is a risk factor for poor healing of diabetic ulcers and for lower limb amputation. Thus, diabetic ulcers are classified as neuropathic, ischemic or neuroischemic (1) .
Diabetic ulcers generate significant suffering and financial costs for the patients, in addition to overloading family members and health professionals and services, emphasizing the need for strategies that include elements of prevention, patient and team education, multidisciplinary treatment and rigorous monitoring (2) .
Diabetic ulcer treatment should include relief of plantar pressure, removal of calluses, protection and drainage of blisters, treatment of fungal infections, intervention to accelerate healing, foot self-care guidelines and management of peripheral artery disease, in order to reduce ulceration complications such as delays in the healing process, presence of infections and lower limb amputations (1) .
In Spain, 44.1% of the patients with diabetes mellitus had neuroischemic ulcers, of which 20.3% were neuropathic and 20.3% were ischemic, with presence of infection as an aggravating factor in 41.4% of the cases (3) . The cumulative incidence of diabetic ulcers in Japan was 0.2% at 12 months, 2.4% at 60 months and 5.8% at 120 months, and most of these patients did not return for reevaluations (4) , highlighting the importance of care continuity and of implementing health education strategies to improve adherence to the therapy and prevent foot complications. A Brazilian study found that 1.9% of the patients with diabetes mellitus had diabetic ulcers, 59% had diabetic neuropathy, 69.6% were at risk of developing diabetic foot, and 86.3% of the patients reported never having undergone any clinical foot examination (5) .
Diabetic ulcers can be caused by trauma, inappropriate shoes, mycotic infections, nail problems, calluses, dry skin and cracks (2,6) . In addition to that, a study verified that patients with moderate knowledge about self-care practices were more likely to perform foot self-care, dry the interdigital spaces, moisturize the feet with creams and observe the presence of mycosis and ingrown toenails, when compared to those with insufficient knowledge (7) .
Diabetic foot is a complication that requires thorough monitoring and behavioral changes. Thus, educational technologies can be effective in controlling diabetes mellitus, stimulating the promotion of foot care and, in the long term, they can enable a reduction in costs, foot complications and amputations (8) . In this perspective, an educational intervention, with a practical skills session and foot care kit, reduced the risk factors for ulceration and improved the preventive behavior of foot self-care (6) .
Training sessions, verbal guidelines, leaflets, apps, videos and didactic games are educational technologies that can be used for the health education of professionals and patients with diabetes mellitus. Thus, structured education, callus removal, use of therapeutic footwear and physical exercises related to the feet and mobility are beneficial to improve modifiable risk factors for foot ulcerations (9) . In addition, the digital educational technology developed for nurses allows greater reach due to ease of access and to time, spatial and schedule flexibility, in addition to offering reduced costs. This educational strategy enables professional updating, qualification and training, contributing to the implementation of preventive interventions to reduce foot complications in patients with diabetes mellitus (8) . In view of the above, this systematic review and meta-analysis aimed at analyzing the effects of educational technologies in the prevention and treatment of diabetic ulcers.

Type of study
This is a systematic review and meta-analysis prepared according to the recommendations set forth in the Cochrane collaboration, based on the following stages: 1) Elaboration and registration of the systematic review protocol; 2) Delimitation of the guiding question; 3) Definition of the eligibility criteria; 4) Search and selection of studies; 5) Data collection; and 6) Synthesis and presentation of the systematic review results (11) .
The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA) guidelines were adopted to draft the systematic review and metaanalysis report (12) .
The review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO), under number CRD42021287241 (13) .

Locus
The systematic review and meta-analysis was conducted in Teresina, capital city of Piauí, Brazil.

Period
The systematic review and meta-analysis took place from January to October 2022.

Eligibility criteria
The materials included were randomized controlled clinical trials that evaluated the effects of using educational technologies in the prevention and treatment of diabetic ulcers in patients with diabetes mellitus, without any time or language restrictions. The exclusion criteria were as follows: course completion papers, monographs, book chapters and materials that did not answer the guiding question. It is emphasized that randomized controlled clinical trials do not usually include the Gray Literature, that is, the one consisting of course conclusion papers, monographs and book chapters, representing an exclusion criterion in this study.  Selection of the studies was initially developed by two reviewers, independently and blindly, following the stages indicated in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement, namely: identification, screening and inclusion (12) . The first step was to read the titles and abstracts. After applying the inclusion and exclusion criteria, the studies were eligible for the next stage, which consisted in reading the full-texts. The inclusion and exclusion criteria were applied again to reach the review sample. It is noted that, in the selection stage, there was disagreement between both reviewers regarding the inclusion of 12 studies; therefore, a third reviewer was called upon.

Bibliographic survey and search strategy
Subsequently, a manual search was performed in the references of the studies included. The Rayyan app was used to store, organize and remove duplicates and to blindly select the studies (15) . It is noted that the Rayyan app version used was the free one. In addition to that, the team of reviewers underwent prior training to learn how to use this tool in selection of the studies. Search and selection of the studies were carried out from January to May 2022.

Data collection
Data extraction was by means of a form prepared by the authors of this review, containing the following items: authors; title of the study; year of publication; study locus; population and sample; information about the method; randomization; blinding; statistical analysis; follow-up time; type and classification of the educational technology; intervention group; control group; main results; and conclusion. Data collection was carried out independently by two reviewers, from June to August 2022. In relation to the items and/or divergent information, meetings were scheduled between the reviewers to discuss and resolve the discordant aspects until reaching consensus.

Data treatment and analysis
To assess the risk of bias in the randomized controlled clinical trials, we used the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2), proposed by the Cochrane collaboration, which has five domains: bias arising from the randomization process; bias due to deviations from intended intervention; bias due to missing outcome data; bias in measurement of the outcome; and bias in selection of the reported result (16) .  (17) . The evaluation was performed for each outcome analyzed. In the meta-analysis, the outcomes Lira JAC, Rocha ASC, Bezerra SMG, Nogueira PC, Santos AMR, Nogueira LT.
The descriptive synthesis of the randomized controlled clinical trials included is presented in Figure 2.
Authors n=29/Usual care in diabetes (did not use any educational technology).

Healing of diabetic ulcers:
The mean ulcer size in the IG * decreased over time when compared to the CG † . Although not healing completely, the difference in ulcer size reduction was statistically significant between both groups (p<0.001).
*IG = Intervention Group; † CG = Control Group; ‡ I = Incidence as with high risk of bias. Seven studies (21)(22)(23)(24)26,(28)(29) were evaluated as with high risk in the bias domain in measurement of the results, as there was no blinding of the outcome evaluators. Four studies (21,24,26,28) had a high risk in the bias domain due to deviations from the designated interventions, as a result of lack of blinding of the participants and the professionals who applied the intervention. One study (25) was classified as having uncertain risk of bias, as it does not specify whether there was blinding of the evaluators. One study (24) has some concern in the domain bias resulting from the randomization process, as randomization was performed but there are no details of the process in the method.
One study (29) presented some concern in the bias domain due to deviations from the designated interventions, as it did not clearly specify whether there was blinding of the professionals who applied the intervention.
In Figure 4 A.1, the Higgins inconsistency statistical test (I 2 ) classified heterogeneity across the studies as substantial (I 2 =70%). In contrast, in Figure 4 A.2, heterogeneity was indicated as not important (I 2 =0%).  [22][23][24]26) and the risk of foot complications (27) . In addition to that, the theoretical-practical training sessions, which are soft-hard technologies, and the Telemedicine apps and mobile phone use, which are classified as hard technologies, improved diabetic ulcer healing and reduced the incidence of lower limb amputations in the intervention groups (21,28) .
Educational technologies consist of knowledge enriched by human action, and are not merely about the construction and use of devices; they involve a systematic set of diverse scientific knowledge that enables planning, execution, control and monitoring of the educational process (30) . From this perspective, the particularities of the educational technologies explain the prevalence of softhard and hard technologies in the randomized controlled clinical trials included in this systematic review.
It was evidenced that eight randomized controlled clinical trials (19)(20)(22)(23)(24)(25)(26)(27) used soft-hard and/or hard educational technologies for the prevention of diabetic ulcers, which were effective in reducing the incidence of ulcerations in five studies (19,(22)(23)(24)26) . On the other hand, three randomized controlled clinical trials (21,(28)(29) used soft-hard and/or hard educational technologies in the treatment of diabetic ulcers, of which two (21,28) found a considerable effect and recorded a higher percentage of total diabetic ulcer healing. presented a significant effect in reducing the incidence of diabetic ulcers, as the Intervention Group had an incidence of 0% and the Control Group, 10%. In addition, they contributed to lowering the Body Mass Index and glycated hemoglobin, reinforcing that brief and low-cost educational technologies can reduce the incidence of foot ulcerations in patients with diabetes mellitus, in addition to being more likely to be applied in the routine clinical practice (26) .
Through a theoretical-practical approach, workshops and interactive practice, classified as softhard technologies, the training sessions proved to be effective in the prevention and treatment of diabetic ulcers and were the most prevalent educational technologies in six studies (21,(23)(24)26,(28)(29) . In Norway, through theoreticalpractical training and Telemedicine, respectively classified as soft-hard and hard technologies, the educational technologies improved diabetic ulcer healing and reduced the number of amputations, as 82.1% of the patients in the Intervention Group presented ulcer healing in 12 months, with 5.1% incidence of amputations in the Intervention Group and 14.1% in the Control Group. In addition to that, this intervention increased the confidence of Primary Health Care nurses, who improved their skills in treating wounds, enabling a more comprehensive care for diabetic ulcers (21) .
The incidence of diabetic ulcers was estimated in six randomized controlled clinical trials (19,(22)(23)(24)(25)(26) . Based on the meta-analysis, it was evidenced that the educational technologies presented a protective factor for preventing the incidence of diabetic ulcers, emphasizing the importance of using these resources in the assistance provided to patients with diabetes mellitus. In a prospective cohort study, the cumulative incidence of diabetic ulcers was 5.6% in two years, with the following risk factors for ulcerations: previous history of ulcerations or amputations, insulin consumption, distal neuropathy and foot deformity (31) . This emphasizes the need for care continuity to control the risk factors and for educational technologies aimed at preventing complications in patients with diabetes mellitus.
In this meta-analysis, the home-based educational session conducted in the United Kingdom with illustrations of injuries on the feet and a handout, classified as softhard technologies, did not present any statistically significant difference between the intervention and control groups regarding the prevention of diabetic ulcer incidence; however, there was an improvement in foot care behaviors in the Intervention Group in relation to checking the shoes before wearing them, daily foot washing and use of moisturizing creams (25)  with the help of a mirror for foot inspection and invited at least one family member to participate in the classes and help the patients, which ensured more effective homebased foot care (24) . foot amputations (22) .
In a systematic review with meta-analysis, thermometry had a protective effect when compared to standard toe care to prevent the incidence of diabetic ulcers (RR=0.53; 95% CI=0.29-0.96; p=0.03), and the authors encourage managers, public health services, professionals, patients, family members and caregivers to implement this preventive technique by monitoring plantar temperature using infrared thermometers, both in the clinical and home contexts (32) . In this systematic review and meta-analysis, two randomized controlled clinical trials used thermometry associated with educational interventions (22)(23) , which may have enhanced the effect of the educational technologies for the prevention of diabetic ulcers.
The incidence of lower limb amputations was estimated in six randomized controlled clinical trials and, in the meta-analysis, the educational technologies presented a protection factor to prevent amputations (21)(22)(24)(25)(26)28) .
In a randomized controlled clinical trial, which employed Telemedicine in the community, classified as a hard technology, the incidence of amputations was 6.4% in the Intervention Group and 14.8% in the Control Group (28) .
However, a study that used soft-hard technologies through a 30-minute face-to-face class and a 90-minute interactive practice on risk behaviors did not record the incidence of amputations between the control and intervention groups, which can be justified due to the brief 6-month follow-up period (26) . to amputation and 16 were in patients who did not adhere to the program (33) .
In this perspective, diabetic foot complications are a public health problem due to the increase in the number of patients with diabetes mellitus, the increased life expectancy of the population and the growth of associated comorbidities. However, the expansion of the assistance provided, which includes both early intervention in patients with diabetic ulcers to avoid gangrene and appropriate treatments such as performing the necessary vascular procedures and mandatory education on foot care, can lead to a reduction in the number of lower limb amputations (34) .
Three randomized controlled clinical trials addressed the effect of educational technologies on diabetic ulcer healing (21,(28)(29) . Although the educational technologies employed, which were soft-hard and hard, did not exert any statistically significant effect on reducing the ulcer healing times (21,28) , there was a reduction in the size of the ulcers (29) , with 82.1% of the patients presenting ulcer healing in the Intervention Group and 76.9% in the Control Group at 12 months. This reinforces that educational technologies should also be used in the diabetic ulcer treatment stage (21) .
The effect of educational technologies on foot selfcare was verified in four randomized controlled clinical trials (20,(24)(25)27) . Even without significant differences in behavioral changes (p=0.26), the attitudes regarding foot self-care increased in both groups (20) . In addition to that, an educational intervention for foot self-care, pressure distribution. This evidences that systematized educational interventions with brief follow-up periods are also effective (27) .
Thus, to enhance the effect, health education should reduce language barriers and involve the patients in their own care plan to raise awareness about the disease and prevent complications, as most patients are unaware of the severity of these complications and follow negligent practices in the long term, due to low education and risky cultural practices. Despite the challenges, health education is a responsibility of professionals, who must use every opportunity to provide specific education, even combining the types of educational technologies available, with the objective of improving the skills of patients with diabetes mellitus in foot self-care (35) .
An integrated care project, which included timely referral, weekly virtual clinic, healthy lifestyle support, community nurse training, app delivery and personalized educational support, increased engagement in education from 5% to 71% of those newly diagnosed with diabetes mellitus, in addition to reducing the incidence of major amputations from 13 to three procedures per 10,000 patients Regarding the satisfaction levels provided by the educational technologies, both randomized controlled clinical trials that evaluated this outcome concluded that there was no statistically significant difference between the intervention and control groups (21,28) . However, the concern with satisfaction in the development of educational technologies is essential, as it influences the participants' adherence to the intervention proposed.
The randomized controlled clinical trials included did not measure the costs of the educational technologies for the prevention and treatment of diabetic ulcers. Thus, the studies pointed out the need to carry out surveys comparing the costs of the educational and monitoring programs implemented with usual care, as it is expected that, in the long term, these interventions will present better cost-effectiveness, cost-benefit and cost-efficacy ratios in preventing foot complications and, consequently, reduce expenditure in health services and improve the quality of life of patients with diabetes mellitus (22)(23)26) . The meta-analysis results indicated that the educational technologies presented a protective factor for preventing the incidence of diabetic ulcers, with substantial heterogeneity across the studies and a low certainty of the evidence assessment, highlighting that, in further research studies, there may be a change in the estimate of the effect. In addition to that, the educational technologies had a protective factor to prevent the incidence of lower limb amputations, when compared to usual care. Heterogeneity was indicated as not important, and certainty of the evidence was assessed as very low.
In view of this, the use of educational technologies is recommended, especially soft-hard and hard, in the prevention and treatment of diabetic ulcers to reduce complications such as non-traumatic lower limb amputations, in addition to conducting more robust and well-designed randomized controlled clinical trials at different care levels for patients with diabetes mellitus, which would later allow developing systematic reviews in different care contexts, with a view to reducing the risk of bias and inconsistencies, as well as improving