Date Published: August 1, 2017
Publisher: Public Library of Science
Author(s): Alide D. Pols, Susan E. van Dijk, Judith E. Bosmans, Trynke Hoekstra, Harm W. J. van Marwijk, Maurits W. van Tulder, Marcel C. Adriaanse, Noel Christopher Barengo.
Given the public health significance of poorly treatable co-morbid major depressive disorders (MDD) among patients with type 2 diabetes mellitus (DM2) and coronary heart disease (CHD), we need to investigate whether strategies to prevent the development of major depression could reduce its burden of disease. We therefore evaluated the effectiveness of a stepped-care program for subthreshold depression in comparison with usual care in patients with DM2 and/or CHD.
A cluster randomized controlled trial, with 27 primary care centers serving as clusters. A total of 236 DM2 and/or CHD patients with subthreshold depression (nine item Patient Health Questionnaire (PHQ-9) score ≥ 6, no current MDD according to DSM-IV criteria) were allocated to the intervention group (N = 96) or usual care group (n = 140). The stepped-care program was delivered by trained practice nurses during one year and consisted of four sequential treatment steps: watchful waiting, guided self-help, problem solving treatment and referral to the general practitioner. The primary outcome was the 12-month cumulative incidence of MDD as measured with the Mini International Neuropsychiatric Interview (MINI). Secondary outcomes included severity of depression (measured by PHQ-9) at 3, 6, 9 and 12 months.
Of 236 patients (mean age, 67,5 (SD 10) years; 54.7% men), 210 (89%) completed the MINI at 12 months. The cumulative incidence of MDD was 9 of 89 (10.1%) participants in the intervention group and 12 of 121 (9.9%) participants in the usual care group. We found no statistically significant overall effect of the intervention (OR = 1.21; 95% confidence interval (0.12 to 12.41)) and there were no statistically significant differences in the course or severity of depressive symptoms between the two groups.
This study suggest that Step-Dep was not more effective in preventing MDD than usual care in a primary care population with DM2 and/or CHD and subthreshold depression.
Depression is projected to be the second cause of disease burden worldwide by 2030. Depression and chronic illnesses such as diabetes mellitus type 2 (DM2) and coronary heart disease (CHD) often occur together and this can lead to a vicious circle, with each being a risk factor for the other. Furthermore, such co-morbidity adversely affects self-care and medication adherence[3,4], quality of life, health status and increases mortality[6,7], and healthcare costs[8,9]. Subthreshold depression, i.e. clinically relevant depressive symptoms without fulfilling the criteria for major depressive disorder (MDD), is the strongest predictor for its onset[10,11]. In addition, people with both subthreshold depression and a history of depression are at even higher risk of another episode of MDD. About a third of the patients with DM2 and/or CHD has subthreshold depression and more than 40% of those will develop MDD within two years[13–15].
In conclusion, this study suggest that Step-Dep was not superior to care as usual in the prevention of MDD in a population with DM2 and/or CHD that screened positively for subthreshold depression. Widespread implementation of Step-Dep in clinical practice in patients screened for subthreshold depression is, therefore, currently not recommended. We recommend further research to evaluate the effectiveness of targeting interventions to patients with more severe depressive symptoms on two consecutive occasions, but only after further exploring their need for care. Our results feed the ongoing debate on the feasibility of stepped-care and screening on (subthreshold) depression in the chronically ill.