Evaluating curvilinear hypothesis in quality of life and glycemic control in diabetic patients

Quality of life (QOL) has become an important concept in medical research. Some research has shown a curvilinear relationship between QOL and glycemic control, but some did not so. The aim of this study is to investigate different aspects of QOL and also assess the hypothesis in diabetic patients. In a cross-sectional study, a random sample of adult diabetic outpatients (n=110) were selected and completed the WHO-QOL assessment instruments. In addition HbA1c was measured in these patients by calorimetric method. Patients were divided in to 3 groups: 1-good control (HbA1c<7), 2-fair control (7≥HbA1c<9) and 3-poor control (HbA1c≥9). QOL was assessed by measuring physical, psychological, social and environmental domains. Data were analyzed with one way ANOVA (Tukey as post hoc), Chi2 and Mann-Whitney, and correlation tests. A significant correlation was seen between BMI and glycemic control, physical and social aspects, physical and environmental aspects, psychological and environmental aspects, and social and psychological aspects. No significant difference was seen between mean score of different dimensions of QOL in relation to HbA1c changes. The mean score of each dimension in relation to glycemic control showed that, better score of psychological, environmental and social dimensions is seen in patients with fair glycemic control. But regarding the overall score of QOL this is completely reverse. The mean score of physical dimension is decreased with increasing HbA1c. There was no correlation between other domains of QOL and glycemic control. In this survey higher quality of life was seen in fair glycemic control in social, environmental and psychological dimensions, but physical dimension in patients was decreased when HbA1c was increased. Regarding the overall score of QOL it can be seen that the lowest score of QOL is in patients with fair glycemic control which is in contrast with curvilinear hypothesis.