Depression screening effective in patients with diabetes
The link between chronic illness and depression has long been recognised by GPs; depression can be a very potent barrier to the effective treatment of any chronic condition. Patients with diabetes are reminded of their condition at every mealtime, and there are also the potential burdens of treatment, testing and complications.
Two recent studies have examined the effectiveness of treating depression in patients with diabetes. Both studies are from the US, so some aspects of the healthcare described are different from UK practice, but the underlying messages are relevant.
Many previous studies of depression in diabetes have used populations of white, middle-class patients. The first study examined the rates of depression, depression treatment and satisfaction with treatment in a multicultural sample of 221 patients. More than half of the patients (53%) were white, and 60% were women. Patients with both types of diabetes were included in the study.
Depression was diagnosed using a validated 20-item questionnaire on depressive symptoms and various types of treatment. Using conservative thresholds, 25% of the population had clinically significant depression.
After adjustment for socioeconomic factors, the rate of depression was not significantly different between ethnic groups, or between patients with different types of diabetes.
Although the rates of depression were similar in all ethnic groups, the rates of treatment and use of professional help were significantly reduced in the African-American group when compared with patients of both white and Hispanic ethnicity. There was no difference across the groups in the use of complementary medicine.
The experience of depression treatment was evaluated in 56 patients with high depression scores. Around three quarters of these patients had experienced one or more types of depression treatment. It was found that 52% had used antidepressant medication, and 63% had been treated by mental health professionals. A substantial minority of the 56 patients used herbal remedies (15%) and alternative healers (19%). Satisfaction with treatment was highest in the group using alternative healers (80%) and lowest in the herbal remedies group (38%). Of those using antidepressant drugs, 63% were satisfied or very satisfied.
This paper supports the high prevalence of coexistent depression in diabetes found in previous studies, such as Goldney et al,1 which was used as supporting evidence for the QOF. The Goldney study found that the lifetime prevalence of depression in patients with diabetes was 24% – three times that of the general population.
The type of diabetes and ethnicity of the patient do not affect this prevalence. The study suggests that treatment of any type is likely to be perceived as helpful, but that some groups of patients may be less likely to access treatment.
The second paper examines the cost effectiveness of treating depression in patients with diabetes. Simon et al examined the costs of care of 329 outpatients with both diabetes and depression. The patients were randomly assigned to either usual care or a multicomponent programme, managed by specialised nurses (I suspect they were the US equivalent of community psychiatric nurses) in primary care. The nurses managed depression with a stepwise approach that included psychotherapy, antidepressant therapy or both, as well as specialist referral when indicated.
In the first year the intensive depression management increased the costs of care compared with the control group by around $700 per patient. This cost was largely offset by a fall in the need for medical outpatient attendances in the intervention group. The intensively treated group also showed significantly reduced mean depression scores, and this difference was maintained until the end of the 24-month study. By the end of the second year the costs of intensive treatment had fallen but the savings continued.
Overall, after adjustment the intensive treatment group benefited from 61 extra depression-free days per patient. The intervention also saved about $300 per patient over the course of the study.
The conclusion is that intensive treatment of depression in diabetes improves medical outcomes and quality of life while remaining cost effective, with savings accruing very quickly after an initial investment.
These papers are relevant to UK general practice as we reflect on our latest QOF achievements. This year the Depression 1 indicator awarded points for ‘the percentage of patients on the diabetes register and/or the CHD register for whom case finding for depression has been undertaken on one occasion during the previous 15 months using two standard screening questions' (see table 1, attached).2
The method of using two questions is based on a study from New Zealand.3 As a screening tool it is specific but not sensitive: a negative response to the questions confidently excludes depression, but there are a significant number of patients who respond positively and do not have the condition.
However, even allowing for the problems of false positives, these two papers support active screening for depression in patients with diabetes as a successful and cost-effective intervention.
In my own practice we send the two screening questions, with a supporting letter of explanation, as part of the invitation to the diabetes clinic. The nurse records the response when the patient attends, and the letters are kept as documentary evidence. Positive responses are not dealt with in the clinic – it would be too complicated. Instead, patients are invited to see their usual GP to discuss the responses further. Patients with depression who are already on treatment are phoned by their usual GP.
We started this system in the summer of 2006, so we have not achieved full points this year, but it does seem to work without unbalancing a busy diabetes clinic.
I wonder if we would have more success with our diabetes management if we were able to pursue patients with positive depression screening responses as intensively as the Simon et al study.
De Groot M, Wagner J, Pinkerman B et al. Depression Treatment and Satisfaction in a Multicultural Sample of Type 1 and Type 2 Diabetic Patients. Diabetes Care 2006;29:549-553
Simon G, Katon WJ, Lin EHB, et al. Cost-effectiveness of Systematic Depression Treatment Among People With Diabetes Mellitus Arch Gen Psychiatry 2007;64:65-72.Reviewer
Dr Matthew Lockyer
GP, Suffolk and hospital practitioner in diabetic medicine