MELBOURNE – Elevated total cholesterol and low-density lipoprotein cholesterol levels in patients with coronary heart disease were significantly associated with an increased risk of chronic kidney disease, according to a retrospective analysis of data from two large, randomized, controlled trials.
Data presented at the World Congress of Cardiology 2014 showed total cholesterol levels above 240 mg/dL were associated with a significant 78% increase in the risk of chronic kidney disease, while LDL cholesterol greater than 190 mg/dL was associated with a 72% increase in risk.
Elevated non–high-density lipoprotein cholesterol levels and the ratio of total cholesterol to HDL cholesterol were both associated with elevated risk of chronic kidney disease, but reduced HDL cholesterol and the ratio of apolipoprotein B/apolipoprotein A did not significantly affect risk.
Dyslipidemia is present in around 60% of patients with chronic kidney disease, noted presenter Dr. Prakash Deedwania, professor of medicine at the University of California, San Francisco. Previous studies in patients with coronary heart disease and chronic kidney disease also have shown that statins have a renoprotective effect.
However, Dr. Deedwania said there has been little exploration of the impact of baseline lipid parameters on renal function.
"We have found that there is a significant increase in not only the prevalence but also the morbidity and mortality in people with chronic kidney disease with coronary events and other cardiovascular events," Dr. Deedwania said in an interview.
Using data from the Treating to New Targets (TNT) study and Incremental Decrease in End Points Through Aggressive Lipid Lowering (IDEAL) study, in which patients were treated with either atorvastatin or simvastatin, researchers were able to examine the relationship between baseline lipoprotein parameters and kidney function in a combined cohort of more than 19,000 patients with coronary heart disease.
"That showed very good relationship between total cholesterol and LDL cholesterol with progressive decline in renal function, which then helped me explain what I had observed earlier in terms of improvement in kidney function in early-stage patients with statins," Dr. Deedwania said at the meeting, which was sponsored by the World Heart Federation.
The relationship between lipoprotein parameters and chronic kidney disease persisted even after adjustment for age, body mass index, smoking status, diabetes history and status, hypertension, and treatment assignment.
The study defined chronic kidney disease as an estimated glomerular filtration rate below 60 mL/min per 1.73 m2. However, Dr. Deedwania said no patients achieved stage 4 kidney disease, and all eGFR measurements fell between 45 and 60 mL/min per 1.73 m2.
The analysis used a relatively early definition of kidney disease as the outcome of interest, observed session chair Dr. Vlado Perkovic, professor of medicine at the University of Sydney (Australia).
Dr. Deedwania later said he believed the key was to focus on early-stage interventions rather than waiting until the disease progressed and suggested some interventional trials had failed to achieve an effect because they were done in more advanced patients.
The researchers declared a range of speakers fees, consultancies, and honoraria from the pharmaceutical industry; two of the authors were employees of Pfizer.