Trajectories of depression in adults with newly diagnosed type 1 diabetes: results from the German Multicenter Diabetes Cohort Study.

Abstract

There is a paucity of longitudinal data on type 1 diabetes and depression, especially in adults. The present study prospectively analysed trajectories of depressive symptoms in adults during the first 5years of living with type 1 diabetes. We aimed to identify distinct trajectories of depressive symptoms and to examine how they affect diabetes outcome. We reanalysed data from a prospective multicentre observational cohort study including 313 adults with newly diagnosed type 1 diabetes. At baseline and in annual postal surveys over 5 consecutive years, we gathered patient characteristics and behavioural and psychosocial data (e.g. Symptom Checklist-90-R [SCL-90-R]). Medical data (e.g. HbA1c levels) was obtained from the treating physicians. We applied growth mixture modelling (GMM) to identify distinct trajectories of depression over time. Five years after diagnosis, 7.8% (n = 20) of patients were moderately depressed and 10.2% (n = 26) were severely depressed. GMM statistics identified three possible models of trajectories (class 1, 'no depressive symptoms'; class 2, 'worsening depressive symptoms that improve after 2years'; class 3, 'worsening depressive symptoms'). Severity of depression symptoms at baseline (subscale of the SCL-90-R questionnaire) significantly predicted membership of classes 2 and 3 vs class 1. After 5years, higher HbA1c values were detected in class 3 patients (mean = 8.2%, 66mmol/mol) compared with class 1 and class 2 (both: mean = 7.2%, 55mmol/mol). We identified distinct trajectories of depressive symptoms that are also relevant for diabetes outcome. Patients with worsening depressive symptoms over time exhibited poor glycaemic control after the first 5years of living with diabetes. They also exhibited a reduced quality of life and increased diabetes-related distress.