Traditionally, a high level of "bad" cholesterol (LDL) is considered an indicator of the risk of myocardial infarction.

A recent study by Canadian scientists has shown that it does not apply to patients with chronic renal failure (CRF).

In this group of patients, at low rates of estimated glomerular filtration rate (rSCF), the association between LDL and risk of infarction was the least predictable.

The study was conducted by Dr. Marcello Tonelli, Professor of the Faculty of Medicine, University of Alberta. The results of the work were published on May 16 in the Journal of the American Society of Nephrology.

The study included 836,000 patients from the Alberta Renal Disease Network who had fasting LDL, RCFR, and urinary protein. During a 48-month follow-up, 7,762 study participants were hospitalized with myocardial infarction.

It is known that patients with chronic renal insufficiency have a high risk of cardiovascular disease, and the level of LDL is not a reliable indicator of the risk of myocardial infarction in patients on hemodialysis. Much less we know about the exact relationship between the level of LDL and coronary risk in patients with less severe chronic renal failure. Although they, as the researchers say, a heart attack is also one of the main causes of death and disability.

The authors write: "Previous studies have studied the relationship between serum cholesterol and cardiovascular events in patients with CRF that are not dependent on dialysis. These studies have come up with contradictory results ".

In the current study, it was found that the lower the rate of RSKF, the less predictable is the relationship between the level of LDL and the risk of myocardial infarction.

The adjusted ratio of the chances of infarction (95% CI) for patients with an LDL level of more than 4.9 mmol / l was as follows:.

• 2.06 (from 1.59 to 2.67) for rSCF 15-59.9 ml / min / 1.73 m 2.

• 2.30 (from 2.00 to 2.65) for rSCF 60-89.9 ml / min / 1.73 m 2.

• 3.01 (from 2.46 to 3.69) for rSCF more than 90 ml / min / 1.73 m 2.

The results of the study on the risk of ST-segment elevation myocardial infarction (STEMI) were similar to those reported above.

The odds ratio (95% CI) of STEMI at an LDL level above 4.9 mmol / L compared to the control group was:.

• 2,32 (from 1,47 to 3,68) for rSKF 15-59,9 ml / min / 1,73 m 2.

• 2.28 (1.81 to 2.87) for rSCF 60-89.9 ml / min / 1.73 m 2.

• 3.29 (from 2.40 to 4.51) for rSCF more than 90 ml / min / 1.73 m2.

Other factors, such as poor nutrition and inflammation in patients with CRF, may at least partially explain the difference in results compared to the general population. The authors note that the fact of unreliability of the level of LDL as an indicator of the risk of heart attack in such patients is of great clinical importance.

Current clinical guidelines recommend Western patients with CKD not on dialysis-dependent, based on the indicator of the level of LDL in the assessment of coronary risk and the appointment of cholesterol-lowering therapy. The results of this paper do not support this practice, so the authors favor a more "liberal" approach to using statins in a given population.

The authors say: "Given the high coronary risk and high mortality due to myocardial infarction in patients with CRF, and also evidence of high efficacy of hypocholesterolemic therapy, we propose to use statins more widely for this patient population".

In his commentary, Dr. Julia Lin, associate professor at the Harvard School of Medicine, agrees with the clinical significance of the new data, but does not share the view on a more liberal statin prescription. She notes: "Before a significant change in the standard of therapy, a larger, randomized trial is needed".

Dr. Lin also lists a number of "knowledge gaps" that we still need to address in this issue. Among these gaps: an independent effect of kidney function on coronary risk, the influence of neurohormonal factors, etc..

She also raised questions about inflammatory biomarkers as potential mediators in the association between kidney function and coronary risk. She speaks about the possibility of using these biomarkers to assess the risk of heart attack in patients with CRF.

These gaps, according to Dr. Lin, can be eliminated "by more frequent inclusion in clinical trials of participants in CRF". A high risk of heart attack in this population requires additional studies with such patients.

It should be noted that in the last study there were several limitations. The incidence of myocardial infarction was assessed on the basis of records of hospitalization, but not based on interviews with patients. The authors of the study did not have enough data on the nutrition of patients and the level of inflammation markers, which Dr. Lyn.

Data on medications taken were available only to 33% of study participants, which can also make adjustments to medbe results. en.

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