Background
Diabetes is a condition that causes high levels of sugar in the blood. Blood sugar levels are controlled by insulin, a hormone made by the pancreas. Insulin instructs the liver, muscles and fat cells to remove sugar from the blood and store it. When the pancreas does not make enough insulin, or the body does not respond to insulin, too much sugar stays in the blood.
High blood sugar can damage the nerves in the body’s extremities (such as the hands or feet) and cause numbness. This means that if someone with diabetes cuts their foot by stepping on a sharp object, or develops blisters on their feet, they might not be aware if it. Blisters may develop into open wounds or sores, known as diabetic foot ulcers (DFU). These can be slow to heal, because diabetes damages blood vessels and this restricts blood supply – and the oxygen and nutrients blood carries, which are necessary for healing. If left untreated, ulcers can become infected. In severe cases, amputation of a toe, foot, or more, may be necessary.
People with DFU may feel distressed about their wounds and the impact these have on their life. This can reduce chances of ulcers healing, and make them more likely to reappear. Psychological therapies might improve ulcer healing and prevent reappearance, by helping people to feel that they can manage their diabetes and overcome DFU.
What did we want to find out?
We wanted to find out if psychological therapies improve DFU healing and prevent their reappearance. We also wanted to know if they affect the number of amputations, quality of life, cost of treatment and people's belief that they can manage the condition, in addition to comparing the effects of different psychological therapies.
Our methods
We searched for relevant randomised controlled trials, in which the treatment each person receives is chosen at random. These studies give the most reliable evidence about the effects of a treatment. We then compared the results, and summarised the evidence from all the studies. We assessed how certain the evidence was by considering factors such as the way studies were conducted, study sizes, and consistency of findings across studies. Based on our assessments, we categorised the evidence as being of very low, low, moderate or high certainty.
What we found
We found seven studies that involved 290 people with diabetes who were followed up for between six weeks and six months. The studies were conducted in Australia, the USA, Norway, Indonesia, South Africa and the UK. The psychological therapies investigated were:
- counselling (three studies);
- muscle relaxation (one study);
- individually-tailored motivation (one study);
- a therapy that aims to develop a person’s understanding of well-being (one study);
- group-based cognitive behavioural therapy (one study).
Psychological therapies compared to usual care
We do not know if psychological therapies improve healing of DFU, or prevent ulcer reappearance, because the evidence is of very low certainty.
Different psychological therapies compared to each other
We do not know if some psychological therapies have more of an effect than others on healing of DFU or preventing ulcer reappearance. This is because either no studies investigated this, or the evidence is of very low certainty.
We do not know if psychological therapies have an effect on the time it takes for ulcers to reappear, amputation, quality of life or a person’s belief in their ability to manage their condition, because there were either no or too few studies investigating this. No studies reported information about the cost of psychological therapies.
What does this mean?
There is no robust evidence about the effects of psychological therapies on DFU healing and recurrence.
There is a need for high-quality studies that include enough people to detect a potential effect of psychological therapies on ulcer healing or reappearance. It would be helpful to agree on a set of clear measures to include in all future studies, so that results from different studies could be compared and analysed together.
How-up-to date is this review?
The evidence in this Cochrane Review is current to September 2019.
We are unable to determine whether psychological interventions are of any benefit to people with an active diabetic foot ulcer or a history of diabetic foot ulcers to achieve complete wound healing or prevent recurrence. This is because there are few trials of psychological interventions in this area. Of the trials we included, few measured all of our outcomes of interest and, where they did so, we judged the evidence, using GRADE criteria, to be of very low certainty.
Diabetic foot ulceration (DFU) can be defined as a full-thickness wound below the ankle and is a major complication of diabetes mellitus. Despite best practice, many wounds fail to heal, and when they do, the risk of recurrence of DFU remains high. Beliefs about personal control, or influence, on ulceration are associated with better engagement with self-care in DFU. Psychological interventions aim to reduce levels of psychological distress and empower people to engage in self-care, and there is some evidence to suggest that they can impact positively on the rate of wound healing.
To evaluate the effects of psychological interventions on healing and recurrence of DFU.
In September 2019, we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE (including In-Process & Other Non-Indexed Citations), Ovid Embase, Ovid PsycINFO and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and reviewed reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.
We included randomised controlled trials (RCTs) and quasi-RCTs that evaluated psychological interventions compared with standard care, education or another psychological intervention. Our primary outcomes were the proportion of wounds completely healed; time to complete wound healing; time to recurrence and number of recurrences.
Four review authors independently screened titles and abstracts of the studies identified by the search strategy for eligibility. Three authors independently screened all potentially relevant studies using the inclusion criteria and carried out data extraction, assessment of risk of bias and GRADE assessment of the certainty of the evidence.
We identified seven trials that met the inclusion criteria with a total of 290 participants: six RCTs and one quasi-RCT. The studies were conducted in Australia, the USA, the UK, Indonesia, Norway and South Africa. Three trials used a counselling-style intervention and one assessed an intervention designed to enhance an understanding of well-being. One RCT used a biofeedback relaxation training intervention and one used a psychosocial intervention based on cognitive behavioural therapy. A quasi-RCT assessed motivation and tailored the intervention accordingly.
Due to the heterogeneity of the trials identified, pooling of data was judged inappropriate, and we therefore present a narrative synthesis. Comparisons were (1) psychological intervention compared with standard care and (2) psychological intervention compared with another psychological intervention.
We are uncertain whether there is a difference between psychological intervention and standard care for people with diabetic foot ulceration in the proportion of wounds completely healed (two trials, data not pooled, first trial RR 6.25, 95% CI 0.35 to 112.5; 16 participants, second trial RR 0.59, 95% CI 0.26 to 1.39; 60 participants), in foot ulcer recurrence after one year (two trials, data not pooled, first trial RR 0.67, 95% CI 0.32 to 1.41; 41 participants, second trial RR 0.63, 95% CI 0.05 to 7.90; 13 participants) or in health-related quality of life (one trial, MD 5.52, 95% CI -5.80 to 16.84; 56 participants). This is based on very low-certainty evidence which we downgraded for very serious study limitations, risk of bias and imprecision.
We are uncertain whether there is a difference in the proportion of wounds completely healed in people with diabetic foot ulceration depending on whether they receive a psychological intervention compared with another psychological intervention (one trial, RR 2.33, 95% CI 0.92 to 5.93; 16 participants). This is based on very low-certainty evidence from one study which we downgraded for very serious study limitations, risk of bias and imprecision.
Time to complete wound healing was reported in two studies but not in a way that was suitable for inclusion in this review. One trial reported self-efficacy and two trials reported quality of life, but only one reported quality of life in a manner that enabled us to extract data for this review. No studies explored the other primary outcome (time to recurrence) or secondary outcomes (amputations (major or distal) or cost).