The longitudinal association between glycaemic control and health-related quality of life following insulin therapy optimisation in type 2 diabetes patients. A prospective observational study in secondary care.

Purpose: To test whether improvement in glycosylated haemoglobin (HbA(1c)) as a marker of glycaemic control, following intensifying insulin therapy, is associated with improvements in HRQoL.
Methods: Dutch sub-optimally controlled (HbA(1c) > 7%) type 2 diabetes patients (N = 447, mean age 59 ± 11) initiated insulin glargine therapy. Data were collected at baseline, 3 and 6 months, and included HbA(1c) and measures of HRQoL: diabetes symptom distress (Diabetes Symptom Checklist-revised; DSC-r), fear of hypoglycaemia (Hypoglycaemia Fear Survey; HFS-w) and emotional well-being (WHO-5 wellbeing index).
Results: HbA(1c) decreased from 8.8 ± 1.4% to 8.0 ± 1.2% and 7.7 ± 1.3% at 3 and 6 months follow-up, respectively (P < 0.001), DSC-r score improved from 17.7 ± 14.7 to 14.3 ± 13.3 and 13.6 ± 13.3 (P < 0.001). HFS-w score did not significantly change. WHO-5 score increased from 56 ± 23 to 62 ± 23 and 65 ± 22 P < 0.001). A modest, significant association was found between HbA(1c) and WHO-5 score (B = -1.8, 95% CI: -2.7 to -0.8) and HbA1c and DSC-r score (B = 1.0, 95% CI: 0.4 to 1.6). No such association was found for HFS-w score.
Conclusions: An association between improvement in HbA(1c) by means of optimising insulin therapy and improvement in HRQoL in type 2 diabetes patients has been observed. A weak, yet significant longitudinal association was found between improved HbA(1c) and emotional well-being and diabetes symptom distress.