People with systemic lupus erythematosus (SLE) are more prone to developing metabolic syndrome — a cluster of metabolic and cardiovascular risk factors that include hypertension, obesity, poor glucose tolerance, and high levels of cholesterol and triglycerides, like fat, in the blood — than others, new study reports, noting the syndrome as a likely cause of heart disease in these patients.
The study, “Prevalence and risk of metabolic syndrome in patients with systemic lupus erythematosus: A meta-analysis,” was published in the International Journal of Rheumatic Diseases.
Lupus patients are considered to be at risk of coronary heart disease (plaque buildup within the coronary arteries), with chances of a cardiovascular event estimated to be seven to 17 times higher in these patients than in the general population. Cardiovascular disease, in fact, is a known cause of mortality in people with lupus for longer than five years. But while this link has been demonstrated in numerous studies, the reason for it are not fully understood.
One possible factor is the presence of metabolic syndrome, as patients with this syndrome are prone to heart disease. Previous studies have also shown that metabolic syndrome is more common in lupus patients than in the general population.
However, metabolic syndrome’s prevalence among lupus patients in these studies varies widely, ranging from 3.3 percent to 45.2 percent. Researchers at the First Hospital of China Medical University, therefore, conducted a meta-analysis to better specify the prevalence of metabolic syndrome in lupus, and the relationship between the two illnesses.
For the first analysis, they looked at data from 47 studies published between 2006 and 2016, involving a total of 8,367 SLE patients. For the second, they analyzed 24 studies, involving 2,744 lupus patients and 3,028 controls.
Pooled data showed the prevalence of metabolic syndrome was 26 percent in lupus patients. Statistical analysis further determined that the risk of metabolic syndrome in SLE patients was 1.88 times higher than in the control group.
Lupus patients in Africa had the highest prevalence of metabolic syndrome at a rate of 38 percent, with those in South America just behind, at 35 percent. Metabolic syndrome was least prevalent among lupus patients in Europe, at 21 percent.
Only lupus patients in Europe, North and South America, and Asia were found to more prone to metabolic syndrome than the general population. This finding means that, even though metabolic syndrome was most prevalent among lupus patients in Africa, the rate of prevalence was not statistically different than among the population at large.
Differences in metabolic syndrome rates worldwide could be attributed to a number of factors, such as genetics, environment, lifestyle changes, nutrition, and publication biases.
The link between lupus and cardiovascular disease, the researchers concluded, could well be due to the prevalence of metabolic syndrome in these patients. Particularly relevant is that lupus is characterized by chronic inflammation, and both metabolic syndrome and cardiovascular disease can be triggered by excessive inflammation.
“The analysis,” they wrote, summarized “all relevant researches and provided valuable evidence for prevention and treatment.”