Associations between Diabetes and Quality of Life among Breast Cancer Survivors

OBJECTIVE: We aimed to investigate the associations between diabetes and quality of life (QOL) among breast cancer survivors. METHODS: A cross-sectional survey was conducted at 34 Cancer Recovery Clubs across China from May 2014 to January 2015. Quality of life was measured by the Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30) and the Quality of Life Questionnaire-Breast Cancer Module 23 (QLQ-BR23, simplified Chinese version). Information on social-demography, diagnosis and treatment of tumors, and diabetes mellitus were collected by self-reported questionnaires. Univariate analyses of covariance (ANCOVA) was performed to assess the difference in QOL between patients with or without diabetes mellitus, and multiple linear regression models were used to examine the associations after controlling for confounders. RESULTS: Diabetes, both of type 1 diabetes (T1DM) and type 2 diabetes (T2DM) significantly reduced QOL. This effect of diabetes on QOL is independent of tumor size, regional lymph node metastasis, distant metastasis and tumor stage index (TNM). After adjusting for different social-demography, diagnosis and treatment of the tumor, the tumor’s stage and other chronic comorbidities, breast cancer survivors with diabetes got significantly lower scores in functional dimensions (including physical, role, emotional and social functionings measured by EORTC QLQ-C30; body image (BRBI) and future perspective (BRFU) measured by QLQ-BR23, as well as economic difficulties than those without diabetes (P(adjusted)<0.05). Diabetic patients also obtained higher scores in symptom dimensions, including fatigue, nausea and vomiting, pain, dyspnoea, insomnia, constipation and diarrhoea measured by EORTC QLQ-C30; side effects, breast symptoms and upset by hair loss measured by QLQ-BR23 (P(adjusted)<0.05). Compared to patients with T1DM, those with T2DM are likely to suffer more by loss of functioning. CONCLUSIONS: Diabetes was associated with the decreased QOL for breast cancer survivors.