Abstract
AIMS/HYPOTHESIS: Hyperglycaemia and dyslipidaemia are common metabolic abnormalities in adults with type 1 diabetes and both increase cardiovascular disease (CVD) risk. The hypothesis of this study was that change in HbA(1c) over 6 years would be associated with change in fasting lipids in adults with type 1 diabetes. METHODS: The Coronary Artery Calcification in Type 1 Diabetes (CACTI) study examined 652 patients with type 1 diabetes (54% female); 559 and 543 had follow-up visits at 3 and 6 years. Baseline age (mean ± SD) was 37 ± 9 years, diabetes duration 23 ± 9 years, and HbA(1c) 8.0 ± 1.3%. Use of dyslipidaemia medication was 17%, 32%, and 46% at the three visits. Separate longitudinal mixed models were fitted to examine the relationship between change in HbA(1c) and change in fasting total cholesterol (TC), HDL-cholesterol (HDL-c), LDL-cholesterol (LDL-c), log triacylglycerols (TG), and non-HDL-cholesterol (non-HDL-c). Because of an interaction between dyslipidaemia medication use and association of HbA(1c) with lipids, results were stratified by dyslipidaemia medication use. RESULTS: Among patients not using dyslipidaemia medication, a higher HbA(1c) was associated with significantly worse levels of the lipids TC, LDL-c, TG and non-HDL-c (per 1% change in HbA1c, TC 0.101 mmol/l, 95% CI 0.050, 0.152; LDL-c 0.103 mmol/l, 95% CI 0.058, 0.148; TG 0.052 mmol/l, 95% CI 0.024, 0.081; and non-HDL-c 0.129 mmol/l, 95% CI 0.078, 0.180) but not HDL-c (-0.20 mmol/l, 95% CI -0.047, 0.007). The associations between HbA(1c) and any lipid outcome among those on dyslipidaemia medication were in the same direction, but attenuated compared with persons not on medication. CONCLUSIONS/INTERPRETATION: Change in HbA(1c) is significantly associated with change in fasting lipids, but dyslipidaemia medications may be required to optimise lipid and cardiovascular health.