Can a Simple Blood Test Predict COPD Severity?
COPD severity is usually assessed based on symptoms, physical signs, and response to therapy, but according to researchers from Northern Israel, a blood test may be a more accurate and much simpler way to determine it.
Their study investigated the relationship between COPD exacerbation severity and complete blood count (CBC) parameters such as hemoglobin level, mean corpuscular volume (MCV), mean platelet volume (MPV), and red blood cell distribution width (RDW) in 1011 patients who had been hospitalized with an acute exacerbation. Overall, 804 patients made it into the final analysis.
PaCO2 levels were used to measure COPD exacerbation severity, along with length of the hospital stay and other parameters, then those measures were compared to the blood test results. Specific findings include —
- PaCO2 was significantly higher in patients with MCV greater than 100 fL (62 mmHg) vs. patients with normal (56 mmHg) or low MCV (52 mmHg).
- PaCO2 was also higher in patients with RDW above 15 fL compared with patients with normal RDW (58 mmHg vs. 53 mmHg).
- High RDW and CRP levels were associated with a longer hospital stay.
- Patients with RDW greater than 18 fL were more likely to have a stay of 7.5 days, compared with 5.9 days for those with RDW levels between 14 and 18 fL, and 5.1 days for those with RDW less than 14 fL.
- Patients with elevated CRP levels had significantly longer hospital stays than those with normal CRP levels, 6.1 days vs. 4.5 days.
The authors believe the positive correlation between RDW and CRP levels seen in their study supports previous work suggesting RDW is a good biomarker of acute inflammation. They also believe blood tests can add value to COPD severity predictions.
“Inexpensive and simple laboratory parameters can be considered as biomarkers of the severity of COPD exacerbation, and their use to escalate the treatment of COPD exacerbation should be further investigated,” they wrote. The study was published by the Journal of Personalized Medicine. Read More
Person-to-Person Spread of Deadly Bacterium Called into Question
A little know pathogen called Mycobacterium abscessus that poses a significant risk for serious lung infections in people with compromised immunity or reduced lung function may not be as contagious as experts had thought.
According to investigators from Harvard Medical School, previous research showing few genetic mutations of the bacterium in samples taken from cystic fibrosis (CF) patients had led scientists to speculate that M. abscessus could be transmitted person-to-person. Person-to-person spread could be especially worrisome for people with CF because M. abscessus is highly resistant to antibiotics. CF patients who become infected are ineligible for lifesaving lung transplants.
In their study, the Harvard researchers first created a genetic family tree for the bacterium using a large dataset of M. abscessus genomes, then examined branches of the tree with clusters of genetically similar strains to calculate their evolutionary rate.
The results showed those clusters are evolving at a very slow evolutionary rate compared to more typical strains, leading the investigators to conclude fears about person-to-person transmission may not be warranted. The finding could have implications for clinics that treat people with CF, as many have been taking extra precautions due to the bacterium.
“Our results certainly do not refute the possibility of person-to-person transmission of Mycobacterium abscessus in some cases, and more research is needed to inform best clinical practice for vulnerable patients,” said study author Maha Farhat. “However, our work supports a model in which person-to-person transmission may not be as common as it is sometimes suggested to be.”
She and her fellow investigators believe people are more likely to pick up the bacterium from the home or other environmental exposures.
The study was published by PNAS. Read More
Race-Specific Equations Linked to Health Disparities
Researchers from the University of Pennsylvania added to the evidence that race-specific equations used in interpreting pulmonary function tests may be short-changing black individuals in a study published by JAMA Network Open.
The study compared the use of race-neutral equations recently developed by the Global Lung Function Initiative with standard race-specific equations in 8431 individuals to see how the results might change depending on the equations used. Among that group, 2722 were black.
For black participants, replacing the race-specific equations with the race neutral equations led to an increase in the percentage of those identified with restrictive ventilatory impairments from 26.8% to 37.5%. The percentage identified with nonspecific ventilatory impairments rose from 3.2% to 6.5%.
Using the race-neutral equations led to a decline in the percentage of white individuals identified with restrictive impairments, from 22.6% to 18.0%, and a decline in the percentage of those identified with nonspecific impairments, from 8.7% to 4.0%.
The race-neutral equations also had an effect on severity. Among black individuals in the study, severity was worse in 22.8% when compared to the standard equations. Among white individuals severity decreased in 19.3%.
According to the authors, more study is needed to “quantify the effect these reference equations would have on diagnosis, referral, and treatment patterns.” Read More
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