Low cholesterol levels linked to worse outcomes in IPF: Study
Total cholesterol may be 'cost-effective indicator' to predict patient survival
Low total cholesterol levels are linked to a higher risk of death among people with idiopathic pulmonary fibrosis, a new study from China with more than three years of follow-up data found.
“We conducted a long-term follow-up study in patients with IPF and observed that lower [total cholesterol] levels were associated with [an] increased risk of mortality,” the researchers wrote.
According to the team, these findings suggest that total cholesterol levels might help predict survival among people whose pulmonary fibrosis is due to an unknown cause.
“Our study suggests that [total cholesterol], a convenient and cost-effective indicator, can predict the survival of IPF patients,” the researchers wrote, noting, however, that further studies are needed to confirm these early findings.
The study, “Serum cholesterol levels predict the survival in patients with idiopathic pulmonary fibrosis: A long-term follow up study,” was published in the journal Respiratory Medicine.
Low cholesterol levels found to be an indicator of mortality
IPF is a progressive disease characterized by scarring, or fibrosis, of the lungs, causing symptoms like shortness of breath and a dry, hacking cough. It’s called idiopathic because its exact cause is unclear.
While the exact mechanisms underlying the disease need further study, emerging research suggests a link between IPF progression and metabolic changes, particularly in fat (lipid) metabolism.
To shed light on a potential relationship between IPF and fat metabolism, a team of researchers from Nanjing University conducted a retrospective analysis that involved 146 people — 129 males and 17 females — with the condition. The patients’ mean age was 66, and they were followed for a median of 46.5 months, or nearly four years, at a single hospital in China.
Among the patients, the three-year survival rate was 71.23%.
A total of 87 had a history of smoking, 35 had diabetes, 47 had high blood pressure, five had chronic obstructive pulmonary disease, known as COPD, and 11 had a history of heart disease. Antifibrotic therapies were administered to 75 patients, while 13 received fat-lowering therapies, and four underwent a lung transplant.
The team compared the baseline characteristics, or those seen at the study’s start, of the patients who survived with those who did not. The median follow-up was 64 months, or nearly 5.5 years, for surviving patients, and 35 months, or slightly shorter than three years, for those who died.
No significant differences were observed in circulating levels of fatty molecules between the two groups. Age, gender, smoking history, and body mass index, a ratio of weight to height, were nearly identical between the two groups. The use of fat-lowering therapies and comorbidities, or co-occurring conditions, also were nearly the same.
As expected, two measures of lung function — predicted forced vital capacity, or %FVC, and diffusing lung capacity for carbon monoxide, known as %DLCO — were significantly higher in the survival group. FVC measures how much air a person can forcibly exhale after a deep breath, while DLCO assesses the lungs’ ability to transfer oxygen from the air sacs into the blood.
[Total cholesterol levels] could serve as an indicator for mortality in IPF, holding clinical significance in evaluating prognosis.
Significantly more patients in the survival group received antifibrotic therapies (61.54% vs. 43.21%). Patients in the survival group also had a lower risk of mortality, as assessed by the GAP index.
Finally, the researches assessed how circulating lipid levels correlated with lung function. The results showed that a specific class of lipids, called triglycerides, had a positive correlation with %DLCO. A negative correlation was found between triglyceride levels and the GAP index.
In additional statistical analyses, lower total cholesterol levels were identified as an independent risk factor for mortality in IPF patients, even after adjusting for GAP index, smoking history, body mass index, and the use of antifibrotic and lipid-lowering medications.
Overall, according to the researchers, these findings suggest that total cholesterol levels “could serve as an indicator for mortality in IPF, holding clinical significance in evaluating prognosis.” The team noted that their study “demonstrated that low cholesterol levels were associated with poor prognosis in … IPF patients.”
More research must be done to confirm these findings, the researchers noted. Specifically, further studies involving more patients from multiple centers “are needed to determine the relationship between lipid levels and both disease prognosis and severity,” the team concluded.
About the Author
