Neuropathy and presence of emotional distress and depression in longstanding diabetes: Results from the Canadian study of longevity in type 1 diabetes

Highlights

• There is low prevalence of emotional distress and depression (DD) in longstanding T1DM

• Diabetic neuropathy (DN) is associated with higher levels of DD

• Amplified odds of DD in patients with DN are not fully explained by pain symptoms

• Strategies to improve quality of life in patients with DN must go beyond pain control

Abstract

Aim

To determine the association of neuropathy and other complications with emotional distress and depression among patients with longstanding type 1 diabetes (T1DM).

Methods

Canadians with ≥ 50 years of T1DM completed a questionnaire including assessment of distress and depression by the Problem Areas in Diabetes Scale (PAID) and Geriatric Depression Scale (GDS), respectively. Complications were determined using the Michigan Neuropathy Screening Instrument (Questionnaire Component), fundoscopy reports, renal function tests, and self-reported peripheral-(PVD) and cardiovascular (CVD) disease. Associations were analyzed by Poisson regression.

Results

Among 323 participants, 137 (42.4%) had neuropathy, 113 (36.5%) nephropathy, 207 (69.5%) retinopathy, 95 (29.4%) CVD, and 31 (9.8%) PVD. The neuropathy subgroup had higher prevalence of distress (13 (9.5%) vs. 6 (3.3%), p = 0.029) and depression (34 (24.9%) vs. 12 (6.5%), p < 0.001). Adjusting for diabetes complications, neuropathy was associated with higher PAID (adjusted RR 1.44 (95% CI 1.14–1.82), p = 0.003) and GDS scores (adjusted RR1.57 (1.18–2.11), p = 0.002). Independent of potential confounders, neuropathy remained associated with higher PAID (adjusted RR 1.39 (1.10–1.76), p = 0.006) and GDS scores (adjusted RR 1.37 (1.03–1.83), p = 0.032). Associations with neuropathy were not fully explained by neuropathic pain.

Conclusion

Compared to other complications, neuropathy had the greatest association with distress and depression in longstanding T1DM, independent of pain. Strategies beyond pain management are needed to improve quality of life in diabetic neuropathy.

Introduction

Type 1 diabetes mellitus (T1DM) places physical, psychosocial, and behavioral demands on patients and requires lifelong adherence to intensive therapy.1., 2. In older patients with longstanding T1DM, these demands may be augmented by the higher risk of complications including neuropathy, retinopathy, nephropathy, and cardiovascular disease (CVD).³ Many studies have demonstrated an association between diabetes, diabetes complications and impairment in mental health,1., 2., 3., 4., 5. and particular emphasis has been placed on the association between painful diabetic sensory neuropathy with depression.⁶ However, the long-term association between diabetes-related emotional distress and depression with diabetes complications is not known: Specifically, it is unknown if both distress and depression are most strongly related to the presence of diabetic sensory neuropathy compared to other complications and, in turn, if neuropathic pain is the key mediator. This is especially important to determine in elderly patients with T1DM due to their susceptibility to complications and poor mental health outcomes.³

Depression and distress are two major psychiatric outcomes in diabetes, and both are elevated in patients with diabetes of all age groups.1., 7., 8. Depression refers to an affective disorder characterized by symptoms including sad or irritable mood, cognitive or somatic changes, and suicidal ideation.⁹ To screen for major clinical depression in elderly patients, the Geriatric Depression Scale (GDS) was developed by Yesavage et al., and was later shortened to a 15-item questionnaire. Subsequently, the GDS-15 has been validated against several popular depression scales and in various populations, demonstrating sensitivity of 71%–100% and specificity of 78%–85%.10., 11., 12., 13., 14. The questionnaire focuses on mood, life satisfaction, behaviors, and cognitions, but not on somatic manifestations of depression as these symptoms are confounded by those of complex medical illness and frailty. Furthermore, the yes/no format of GDS permits effective self-administration in older persons. These characteristics support the use of the GDS over other tools in older patients with longstanding diabetes and complications.

Diabetes-related distress – a negative emotional response to the burdens of diabetes and management – is a distinct concept from depression, as the former is specific to the psychological, physical, and social burdens of diabetes.1., 15., 16. However, distress and depression share many common symptoms and have been shown to be highly correlated in T1DM.1., 17., 18. The Problem Areas in Diabetes scale (PAID) is a validated 20-item questionnaire measuring distress in areas like anger, frustration with management, fear of complications, and social challenges related to diabetes care.¹⁹

Diabetic neuropathy has been shown to be independently linked to depression, distress and reduced quality of life – especially in older patients – though the mechanisms driving this interaction are not completely understood.1., 20., 21., 22. Previous studies have suggested that it is the painful symptomatology associated with sensory neuropathy that contributes to poor psychological outcomes.20., 21. However, some evidence shows that poor psychological outcomes in neuropathy stem from non-pain factors such as restricted quality of life, perception of symptom and treatment unpredictability, and changes in social self-perception.22., 23. Elucidating the link between neuropathy and its psychological sequelae may allow for more comprehensive management of diabetic neuropathy.

There is a paucity of evidence on neuropathy and psychological outcomes in older patients with longstanding T1DM, despite the key role of diabetes duration in predicting depression and distress.¹ In a unique cohort of older patients with 50 years or more of T1DM, we aimed to determine the magnitude of diabetes distress and depression, as well as the impact of symptomatic diabetic neuropathy and neuropathic pain on these psychological outcomes.