After identifying the studies which seemed to be appropriate for my essay, I narrowed them down to the most up-to-date ones and those with stronger evidence base. I was mainly looking for quantitative type of studies done in the past ten years. When all my articles got collected, I did a first read of them to get a sense of what they were about and how specifically they answered my question. The abstracts at the beginning and conclusions at the end of the papers assisted me with deciding how worthy of inclusion they were. The literature search table presented below was originally conducted by Timmins and McCabe (2005) and contains the detailed description of the articles used in the process of finding evidence for the question being investigated.
When critically appraising the first study listed in the above table, I will be looking at the trustworthiness and value of design and methods of the trial and its relevance to nursing practice (Burls, 2009). Cognitive behavioural therapy in elderly Type 2 diabetes patients with minor depression or mild major depression: study protocol of a randomized controlled trial (MIND-DIA) (Petrak et al. 2010 – see appendix) is a description of the Minor Depression and Diabetes trial, which is part of the 'Competence Network for Diabetes mellitus' funded by the German Federal Ministry of Education and Research. It is a multicentre, open, observer-blinded, parallel group randomized controlled trial. The trial started in May 2009 and the duration of the trial is expected to be 36 months.
The participants are 315 patients aged 65-85, diagnosed with Type 2 diabetes mellitus also suffering from minor depression or mild major depression, recruited in 20 centres in the Rhine-Main and Ruhr areas in a two-stage procedure: Patient Health Questionnaire and Structured Clinical Interview for DSM IV Disorders. The intervention is described as 3 different therapies to improve health related quality of life (HRQoL) for patients with Type 2 diabetes having minor depression or mild major depression: diabetes-specific CBT compared to treatment as usual (TAU) and a guided self-help intervention (SH).
Treatment evaluations are conducted by blinded assessors. As clearly identifiable group interventions were compared to treatment as usual, further blinding is not possible. The randomisation process does not open to manipulation from the researchers or the participants thus reducing bias. The aim is to compare the efficacy of the 3 different treatments. Primary and secondary parameters are aiming to reduce depressive symptoms, prevent the occurrence of moderate/severe major depression and improve glycaemic control, mortality and cost effectiveness. The measures being used to determine the outcome of the trial are fitting for a quantitative study.
Participants are randomised into groups as: 132 in CBT (diabetes-specific CBT in small groups of 4-8, delivered by psychologists), 132 in SH (guided self-help intervention “Successful ageing with Diabetes”, delivered by trained moderators), and 51 in TAU (any treatment option may be applicable). Patients in all groups are having usual diabetic treatment for the first 12 weeks. Thereafter, the two group interventions are receiving one session per month for another year. At the one-year check-up, all groups are being examined as to the primary and secondary outcome variables. A 20% rate of loss to follow-up is expected, accounting for mortality in the sample. All sessions are videotaped and supervised by psychotherapists. Analyses are carried out by the intent-to-treat principle (ITT) including all participants in all groups. In case of any dropouts, the last observation carried forward method (LOCF) will be used in purpose of handling of missing data.
The primary outcome variable is HRQoL as measured by the Short Form-36 Mental Component Summary. Z-values (zero-values) will be obtained by z-transformation of the SF-36 Mental Component Summary score) based on standard deviations of age- and gender-matched reference groups (the larger the value of z, the less probable the experimental result is due to chance). Secondary outcome variables are: HRQoL (physical component as measured by the Physical Component Summary Score), reduction of depressive symptoms (Quick Inventory of Depressive Symptomatology-Clinician Rated; Hamilton Depression Scale), prevention of moderate/severe major depression (Depression module), improvement of glycaemic control (HbA1c), prevention of mortality, and cost effectiveness. Also, mild cognitive impairment (MCI) is going to be measured by a three-step MCI diagnostic instrument.
Results of the research are expected to be demonstrated in 2012. As the trial is still on-going, definite results and conclusions cannot be made at this stage. On completion, the first hypotheses will be ordered as: CBT vs. TAU, 2: CBT vs. SH; the second hypothesis will be tested at a two-sided 5% level only if the first test is significant at a two-sided 5% level. Although the trial is being conducted in Germany, it can be reproducible and generalised, and the above described tests and interventions can be transferrable to any UK setting due to the character of diabetes and depression, as the same physiological and psychological treatments can be applied for any given population.
The review of the articles in the literature search table helps to highlight and compare results from key sources while summarizing and evaluating evidence about the topic in question: Would cognitive behavioural therapy in conjunction with routine diabetic treatment be more efficient in managing depression in patients with Type 2 diabetes than routine treatment alone? According to Cronin et al. (2008), a good literature review is an objective and thorough summary and critical analysis of the relevant available research on the topic being studied to provide explicit information for developing evidence-based care.
The studies listed in the literature search table are controlled randomized trials, plus one systematic literature review of 11 controlled randomized trials. The studies report on quantitative findings of clinical investigations undertaken within strictly controlled settings, groups and interventions. Blinding and randomisation were intended to exclude the possibility of bias. Only one of the studies compares the effect of CBT together with routine diabetic treatment to the effectiveness of self-help groups and routine diabetic treatment alone in patients with Type 2 diabetes and depression (Petrak et al. 2010). This article was discussed above, with the limitation that results of the trial are still not obtainable.
In this study protocol Welschen et al. (2007) reports on the effect of combined behavioural therapy together with managed diabetes care for improving the cardiovascular risk profile of patients with Type 2 diabetes. Patients from general practices in the Netherlands were selected and randomised into an intervention group receiving CBT in addition to diabetic care, and a control group that received diabetic care only. Although the study is investigating the correlation of cardiovascular disease and CBT in diabetes, it clearly concludes that the addition of CBT to routine diabetes care has got a positive effect on patients’ lifestyles. One of the weaknesses of the study was that patients, diabetes nurses and dieticians could not be blinded to the intervention. On the other hand, strength of the study is that the publication of the study design will prevents possible publication bias.
Chernyak et al. (2009) in their work discuss the cost-effectiveness of a diabetes-specific CBT as compared to intensified treatment as usual and to a guided self-help group intervention. The trial is a multicentre, open, observer-blinded, controlled trial, subjects aged 65-85 were randomized into 3 groups for treatment of minor or mild-major depression. The results were not published at the time of the writing up of this essay. The economic evaluation will provide evidence as to how cost-effective the application of CBT is. The strength of the study is that it is the first study conducted in the UK that investigates both the health-related benefits of CBT and the cost-effectiveness of the intervention.
An assessment of the efficacy of CBT for depression in patients with diabetes was carried out by Lustman et al. (1998). The weakness of the study is that there is no comparative to any other treatment outlined in the study. The generalizability of the findings is uncertain due to the relatively small patient group and the fact that treatment was provided by only one psychologist experienced in the use of CBT, so the question arises whether treatment would have had the same effect when administered by other therapists. 51 patients were randomly chosen for treatment, 42 (82.4%) completed the 10 weeks of treatment and 9 (17.6%) dropped out at an early stage (5 in the CBT group and 4 in the control group (P > 0.2). 1 patient withdrew because of assignment to the control group. The results showed that the percentage of patients achieving remission of depression was greater in the CBT group than in the control group (P < 0.001), as well as the percentage of patients with clinical improvement (P = 0.01). After 6 months, the percentage of patients in remission was greater in the CBT group than in the control group (P = 0.03), as well as the percentage of patients with clinical improvement (P = 0.01). The results suggest that improvement in the mental state of the patients positively affected the medical outcomes.
The systematic literature review conducted by Snoek and Skinner in 2002 used MedLine and PsychInfo and included studies published in English peer-reviewed journals between 1990 and 2001, investigating the correlation between psychological interventions and conditions like depression, eating disorders, anxiety, self-destructive behaviour and family conflicts in diabetes. The review reports on little empirical research available in the field of psychological interventions in diabetes and their effects on clinical outcomes. This study clearly suggests though, that CBT can be effectively applied for the treatment of depression in Type 2 diabetes patients.
The evidence found in the above articles indicates that CBT can be successfully used for treatment of depression in Type 2 diabetes patients, and there is evidence that the application of CBT may reduce depressive symptoms and HbA1c. Nevertheless, future research should be done to provide sufficient statistical power and substantiate these preliminary findings. There is lack of clinical trials to support the statement that CBT in conjunction with routine diabetic care would be more efficient in treating depression in Type 2 diabetes than routine care alone.
Conclusion
The evidence gathered in the process of literature search and literature review backs up the theory that application of CBT when used in conjunction with routine diabetes care is useful in treatment of depression in patients with Type 2 diabetes. CBT seems to have relatively positive short-term results in improving both quality of life and glycaemic control of patients with Type 2 diabetes. However, there is still not enough evidence to state that CBT in conjunction with usual diabetic care would be more effective in treating depression in patients with Type 2 diabetes, which is due to limited research and few clinical trials conducted in the UK in this area. Further research is needed in order to work out the best approaches towards psychological counselling for patients with diabetes and depression. Nevertheless, the information found during the literature search process shows that CBT as additional care is obtaining popularity among patients and health professionals. A well-organised healthcare environment run by health-care professionals who are trained to provide CBT would be beneficial for patients with diabetes.
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