LDL Cholesterol Not a Good Marker of CVD in Type 1 Diabetes
Key clinical point: In type 1 diabetes, the ratio of total cholesterol to HDL better predicted CVD than did LDL cholesterol level.
Major finding: The adjusted HR for cardiovascular disease per 1 mmol/L increase in total cholesterol to HDL ratio were 1.06 in those taking lipid medications and 1.08 in those who were not. These hazard ratios reached statistical significance, with a P value of less than .01.
Data source: An observational analysis of 30,778 patients in Sweden with type 1 diabetes who were between the ages of 18 and 79 years and followed for a mean of 7 years.
Disclosures: Dr. Hero had no relevant financial conflicts to disclose.
AT THE ADA ANNUAL SCIENTIFIC SESSIONS
At baseline, the mean age of patients was 46 years and their mean duration of diabetes was 20 years. Compared with the patients not taking lipid medication, those taking lipid medication were older (56 vs. 43 years, respectively), had longer diabetes duration (26 vs. 19 years), were more commonly treated with hypertensive medication (70% vs. 25%), and had a lower mean estimated glomerular filtration rate (75 vs. 87 mL/min per 1.73 m2), as well as a higher risk of CVD (24% vs. 4%).
Baseline lipid values were similar between the two main groups: a mean LDL of 106 mg/dL and a mean ratio of cholesterol to HDL of 3.2 units.
Dr. Hero reported that there were 13.8 CVD events per 1,000 person-years among patients taking lipid-lowering medications, compared with 51.7 events per 1,000 years among those who were not taking lipid medications. The researchers also found that 67.9% of patients with a history of CVD had a CVD event over 7 years of follow-up.
The adjusted hazard ratios per 1 mmol/L increase in LDL for CVD was 1.02 in those taking lipid medications and 1.08 in those who were not. Both hazard ratios were nonsignificant. A similar association was observed in patients aged 40 years and older who had one CVD risk factor at baseline. In this subgroup "there is a slight but weak significance for the LDL as a predictor of cardiovascular disease, but when looking at the octiles [of LDL] you can see no significance at all," Dr. Hero noted.
The adjusted hazard ratios per 1 mmol/L increase in the cholesterol to HDL ratio were 1.06 in those taking lipid medications and 1.08 in those who were not, both statistically significant differences. "There is a strong correlation between CVD and the cholesterol to HDL ratio as a continuous variable; also, when we look at the ratio divided into octiles, we can see an obvious correlation with a linear trend," Dr. Hero said. "The higher the ratio, the stronger the correlation. The same is true for the patients 40 years and older with one CVD risk factor. There is a strong correlation for the ratio as a continuous variable and also a linear trend for the octiles of the ratio."
The findings suggest "there is no support for an LDL treatment target of 100 mg/dL," Dr. Hero concluded. "The ratio of cholesterol to HDL is a significant predictor of CVD in patients without lipid-lowering medication. The ratio of cholesterol to HDL seems to be a more reliable marker for CVD risk when considering primary prevention."
Dr. Hero said that she had no relevant financial conflicts to disclose.
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