Temporal changes in glycaemic thresholds for treatment intensification in type 2 diabetes in an urban Australian setting: the Fremantle Diabetes Study.

ABSTRACT

BACKGROUND: Pharmacotherapy and supportive care for diabetes in Australia are improving, with potential beneficial effects on therapeutic procrastination. AIM: To determine whether glycaemic thresholds for therapeutic intensification in type 2 diabetes changed over the 15 years between phases of the community-based Fremantle Diabetes Study (FDS). METHODS: We studied 531 Phase 1 participants (mean age 62.4 years, 54.2% males, median diabetes duration 3.0 years) with valid data from baseline assessment and five subsequent annual reviews between 1993 and 2001 and 930 Phase 2 participants (mean age 65.3 years, 53.8% males, median diabetes duration 8.0 years) with valid data from baseline and two subsequent biennial reviews between 2008 and 2015. The main outcome measure was HbA1c at assessments before and after change in blood glucose-lowering therapy (average 6 months in Phase 1, 12 months in Phase 2). RESULTS: Ninety-seven participants in Phase 1 and 84 in Phase 2 progressed from diet-based management to oral hypoglycaemic agents (OHA) and 45 and 85 participants, respectively, progressed from diet/OHA to insulin. The median HbA1c was 7.5% (58 mmol/mol) and 6.9% (52 mmol/mol) before OHA initiation in Phases 1 and 2, respectively, and 9.1% (76 mmol/mol) and 7.8% (62 mmol/mol), respectively, before insulin initiation. There were median HbA1c falls of 0.3% (3 mmol/mol) and 1.5% (16 mmol/mol) after OHA and insulin initiation in Phase 1, but no statistically significant changes in Phase 2. CONCLUSIONS: HbA1c thresholds triggering treatment intensification fell between FDS phases, suggesting a more proactive approach to management of glycaemia over time.