F. Pouwer

Depression as a risk factor for the onset of type 2 diabetes mellitus. A meta-analysis

Aims/hypothesisEvidence strongly suggests that depression and type 2 diabetes are associated, but the direction of the association is still unclear. Depression may occur as a consequence of having diabetes, but may also be a risk factor for the onset of type 2 diabetes. This study examined the latter association by reviewing the literature and conducting a meta-analysis of longitudinal studies on this topic.MethodsMedline and PsycInfo were searched for articles published up to January 2005. All studies that examined the relationship between depression and the onset of type 2 diabetes were included. Pooled relative risks were calculated using fixed and random effects models. To explore sources of heterogeneity between studies, subgroup analyses and meta-regression analyses were performed.ResultsNine studies met our inclusion criteria for this meta-analysis. The pooled relative risk was 1.26 (1.13–1.39) using the fixed effects model and 1.37 (1.14–1.63) using the random effects model. Heterogeneity between studies could not be explained by (1) whether studies controlled for undetected diabetes at baseline; (2) the method of diabetes assessment at follow-up; (3) the baseline overall risk of diabetes in the study population; and (4) follow-up duration.Conclusions/interpretationDepressed adults have a 37% increased risk of developing type 2 diabetes mellitus. The pathophysiological mechanisms underlying this relationship are still unclear and warrant further research. A randomised controlled study is needed to test whether effective prevention or treatment of depression can reduce the incidence of type 2 diabetes and its health consequences.

Type 2 diabetes mellitus as a risk factor for the onset of depression: a systematic review and meta-analysis

Aims/hypothesisAn earlier meta-analysis showed that diabetes is a risk factor for the development and/or recurrence of depression. Yet whether this risk is different for studies using questionnaires than for those relying on diagnostic criteria for depression has not been examined. This study examined the association of diabetes and the onset of depression by reviewing the literature and conducting a meta-analysis of longitudinal studies on this topic.MethodsEMBASE, MEDLINE and PsycInfo were searched for articles published up to September 2009. All studies that examined the relationship between type 2 diabetes and the onset of depression were included. Pooled relative risks were calculated using fixed and random effects models.ResultsEleven studies met our inclusion criteria for this meta-analysis. Based on the pooled data, including 48,808 cases of type 2 diabetes without depression at baseline, the pooled relative risk was 1.24 (95% CI 1.09–1.40) for the random effects model. This risk was significantly higher for studies relying on diagnostic criteria of depression than for studies using questionnaires. However, this difference was no longer significant when controlled for year of publication.Conclusions/interpretationCompared with non-diabetic controls, people with type 2 diabetes have a 24% increased risk of developing depression. The mechanisms underlying this relationship are still unclear and warrant further research.

Diabetes Attitudes, Wishes and Needs second study (DAWN2™): Cross‐national benchmarking of diabetes‐related psychosocial outcomes for people with diabetes

The second Diabetes Attitudes, Wishes and Needs (DAWN2) study aimed to assess psychosocial outcomes in people with diabetes across countries for benchmarking.

Are factor analytical techniques used appropriately in the validation of health status questionnaires? A systematic review on the quality of factor analysis of the SF-36

Factor analysis is widely used to evaluate whether questionnaire items can be grouped into clusters representing different dimensions of the construct under study. This review focuses on the appropriate use of factor analysis. The Medical Outcomes Study Short Form-36 (SF-36) is used as an example. Articles were systematically searched and assessed according to a number of criteria for appropriate use and reporting. Twenty-eight studies were identified: exploratory factor analysis was performed in 22 studies, confirmatory factor analysis was performed in five studies and in one study both were performed. Substantial shortcomings were found in the reporting and justification of the methods applied. In 15 of the 23 studies in which exploratory factor analysis was performed, confirmatory factor analysis would have been more appropriate. Cross-validation was rarely performed. Presentation of the results and conclusions was often incomplete. Some of our results are specific for the SF-36, but the finding that both the application and the reporting of factor analysis leaves much room for improvement probably applies to other health status questionnaires as well. Optimal reporting and justification of methods is crucial for correct interpretation of the results and verification of the conclusions. Our list of criteria may be useful for journal editors, reviewers and researchers who have to assess publications in which factor analysis is applied.

Depression and risk of mortality in people with diabetes mellitus : A systematic review and meta-analysis

Objective To examine the association between depression and all-cause and cardiovascular mortality in people with diabetes by systematically reviewing the literature and carrying out a meta-analysis of relevant longitudinal studies. Research Design and Methods PUBMED and PSYCINFO were searched for articles assessing mortality risk associated with depression in diabetes up until August 16, 2012. The pooled hazard ratios were calculated using random-effects models. Results Sixteen studies met the inclusion criteria, which were pooled in an overall all-cause mortality estimate, and five in a cardiovascular mortality estimate. After adjustment for demographic variables and micro- and macrovascular complications, depression was associated with an increased risk of all-cause mortality (HR = 1.46, 95% CI = 1.29–1.66), and cardiovascular mortality (HR = 1.39, 95% CI = 1.11–1.73). Heterogeneity across studies was high for all-cause mortality and relatively low for cardiovascular mortality, with an I-squared of respectively 78.6% and 39.6%. Subgroup analyses showed that the association between depression and mortality not significantly change when excluding three articles presenting odds ratios, yet this decreased heterogeneity substantially (HR = 1.49, 95% CI = 1.39–1.61, I-squared = 15.1%). A comparison between type 1 and type 2 diabetes could not be undertaken, as only one study reported on type 1 diabetes specifically. Conclusions Depression is associated with an almost 1.5-fold increased risk of mortality in people with diabetes. Research should focus on both cardiovascular and non-cardiovascular causes of death associated with depression, and determine the underlying behavioral and physiological mechanisms that may explain this association.

Rates and risks for co-morbid depression in patients with Type 2 diabetes mellitus: results from a community-based study

Aims/hypothesisThere is accumulating evidence that depression is common in people with Type 2 diabetes. However, most prevalence-studies are uncontrolled and could also be inaccurate from selection-bias, as they are conducted in specialized treatment settings. We studied the prevalence and risk factors of co-morbid depression in a community-based sample of older adults, comparing Type 2 diabetic patients with healthy control subjects.MethodsA large (n=3107) community-based study in Dutch adults (55–85 years of age) was conducted. Pervasive depression was defined as a CES-D score greater than 15. Diagnosis of Type 2 diabetes was obtained from self-reports and data from general practitioners.ResultsA number of 216 patients (7%) were identified as having Type 2 diabetes. The prevalence of pervasive depression was increased in people with Type 2 diabetes and co-morbid chronic disease (20%) but not in patients with Type 2 diabetes only (8%), compared with the healthy control subjects (9%). Regression analyses in diabetic patients yielded that being single, being female, having functional limitations, receiving instrumental support and having an external locus of control were associated with higher levels of depression.Conclusions/interpretationThe Results suggest that the prevalence of pervasive depression is increased in patients with Type 2 diabetes and co-morbid disease(s), but not in patients with Type 2 diabetes only. Functional limitations that often accompany co-morbid chronic disease could play an essential role in the development of depression in Type 2 diabetes. These findings can enable clinicians and researchers to identify high-risk groups and set up prevention and treatment programs.

Prevalence of Depression in Individuals With Impaired Glucose Metabolism or Undiagnosed Diabetes: A systematic review and meta-analysis of the European Depression in Diabetes (EDID) Research Consortium

OBJECTIVE Meta-analyses have shown that the risk for depression is elevated in type 2 diabetes. Whether this risk in individuals with impaired glucose metabolism (IGM) or undiagnosed diabetes (UDD) is elevated relative to normal glucose metabolism (NGM) or decreased relative to previously diagnosed type 2 diabetes (PDD) has not been the subject of a systematic review/meta-analysis. This study examined the prevalence of depression in IGM and UDD subjects relative to each other and to NGM and PDD subjects by reviewing the literature and conducting a meta-analysis of studies on this topic. RESEARCH DESIGN AND METHODS EMBASE and MEDLINE databases were searched for articles published up to May 2010. All studies that compared the prevalence of depression in subjects with IGM and UDD were included. Odds ratios (ORs) were calculated using fixed and random-effects models. RESULTS The meta-analysis showed that the risk for depression was not increased in IGM versus NGM subjects (OR 0.96, 95% CI 0.85–1.08). Risk for depression did not differ between individuals with UDD and individuals with either NGM (OR 0.94, 95% CI 0.71–1.25) or IGM (OR 1.16, 95% CI 0.88–1.54). Finally, individuals with IGM or UDD both had a significantly lower risk of depression than individuals with PDD (OR 0.59, 95% CI 0.48–0.73, and OR 0.57, 95% CI 0.45–0.74, respectively). CONCLUSIONS Results of this meta-analysis show that the risk of depression is similar for NGM, IGM, and UDD subjects. PDD subjects have an increased risk of depression relative to IGM and UDD subjects.

Web-based depression treatment for type 1 and type 2 diabetic patients : A randomized, controlled trial

OBJECTIVE Comorbid depression is common in patients with type 1 and type 2 diabetes, adversely affecting quality of life, diabetes outcomes, and mortality. Depression can be effectively treated with cognitive behavior therapy (CBT). The Internet is a new and attractive method for delivering CBT intervention on a large scale at relatively low costs. This study evaluated the effectiveness of Web-based CBT for depression treatment in adults with type 1 or type 2 diabetes, with minimal guidance. RESEARCH DESIGN AND METHODS A randomized controlled trial was conducted in the Netherlands in 255 adult diabetic patients with elevated depressive symptoms. Primary outcomes were depressive symptoms. Secondary outcomes were diabetes-specific emotional distress and glycemic control. Assessments were at baseline, after treatment, and at the 1-month follow-up. RESULTS The Web-based CBT was effective in reducing depressive symptoms by intention-to-treat analyses (P = 0.04, d = 0.29; clinical improvement 41% vs. 24% P < 0.001) and by per-protocol analyses (P < 0.001, d = 0.70; clinical improvement, 56% vs. 24% P < 0.001). The intervention reduced diabetes-specific emotional distress (P = 0.03) but had no beneficial effect on glycemic control (P > 0.05). CONCLUSIONS Web-based CBT depression treatment is effective in reducing depressive symptoms in adults with type 1 and type 2 diabetes. In addition, the intervention reduces diabetes-specific emotional distress in depressed patients.

Diabetes Attitudes, Wishes and Needs second study (DAWN2™): Cross‐national benchmarking indicators for family members living with people with diabetes

The second Diabetes Attitudes, Wishes and Needs (DAWN2) study examined the experiences of family members of people with diabetes for benchmarking and identifying unmet needs or areas for improvement to assist family members and those with diabetes to effectively self‐manage.

Prevalence of comorbid depression is high in out-patients with Type 1 or Type 2 diabetes mellitus. Results from three out-patient clinics in the Netherlands.

Diabet. Med. 27, 217–224 (2010)