Associations between improved glucose control and patient-reported outcomes after initiation of insulin pump therapy in patients with type 2 diabetes mellitus

Background: This study assessed the relationship between changes in glucose control and changes in patient-reported outcomes (PRO)-health-related quality of life (HR-QoL) and treatment satisfaction (TxSat)-in patients with type 2 diabetes initiating insulin pump therapy. Methods: Patients (n=54) initiating insulin pump therapy (Animas® 2020, Animas Corp., West Chester, PA) were studied for 16 weeks. Glucose control was measured with patient-blinded continuous glucose monitoring (CGM) (SEVEN™, DexCom, San Diego, CA) and unblinded glycosylated hemoglobin (A1C) and seven-point self-monitored blood glucose (SMBG) profiles. HR-QoL was measured using the Diabetes Symptom Checklist-Revised (DSC-R) and the EuroQol-5 Dimensions (EQ-5D). TxSat was measured using the Insulin Delivery System Rating Questionnaire (IDSRQ) clinical efficacy and treatment preference scales. Bivariate correlations assessed associations between measures of change from baseline. Results: Decreased A1C was associated only with improvement in IDSRQ clinical efficacy. For CGM and SMBG, reductions in mean glucose concentrations were associated with decreased DSC-R symptoms, improved EQ-5D health utility, and increased IDSRQ perceived clinical efficacy and treatment preference. Reduced glycemic variability was associated with improved EQ-5D health utility and increased IDSRQ treatment preference. CGM and SMBG readings from different times of day/night were differentially associated with all PRO. Conclusions: Findings suggest that A1C, representing an "average" of both high and low blood glucose values throughout the day, may not capture aspects of glucose control with the greatest impact on HR-QoL. Although TxSat was more strongly associated with A1C and mean glucose readings than with glycemic variability, HR-QoL was more strongly associated with glycemic variability.