Interstitial lung abnormalities are
a group of disorders which involve lung inflammation or scarring of the lung
tissue between and supporting the air sacs, which could lead to lung stiffness
and could also affect your breathing abilities in the long run. Rheumatologic
or autoimmune diseases
are some of the known causes of interstitial lung diseases.
lung abnormalities are commonly seen in older individuals and are thought to
lead to early stages of pulmonary fibrosis. In one of the studies, these abnormalities have been linked to
reductions in lung capacity, exercise capacity, gas exchange, amongst others.
‘Interstitial lung abnormalities on CT scans signal higher-than-average mortality within 3-9 years.’
According to a recent study
published in the Journal of
the American Medical Association
, interstitial lung abnormalities were
strongly associated with an increased risk of death.
Lead author Rachel K. Putman, M.D., from the Brigham and Women's
Hospital in Boston, and her associates analyzed data from four prospective
cohort studies to investigate whether interstitial lung abnormalities are
associated with increased mortality.
The study participants were middle-aged to older people from four
separate research cohorts as follows:
- 2,633 from the Framingham Heart Study
- 5,320 from the Age Gene/Environment
Susceptibility (AGES)-Reykjavik Study
- 2,068 from the Chronic Obstructive
Pulmonary Disease (COPD) Gene study
- 1,670 from the Evaluation of COPD
Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study
interstitial lung abnormality was determined by chest CT evaluation
. These imaging abnormalities (which included reticular abnormalities, diffuse centrilobular nodularity, non-emphysematous cysts, honeycombing, traction bronchiectasis, amongst others) were evaluated as specific patterns of increased lung density affecting more than 5% of any lung zone.
seen that interstitial lung abnormalities were found to be present in 177 (7%)
of the participants from FHS, 378 (7%) in the AGES-Reykjavik study group, 156
(8%) in COPD Gene group, and in 157 (9%) participants from ECLIPSE study.
The authors reported that the
presence of interstitial lung abnormalities were linked
to a greater risk of death in all four cohorts over a median follow-up times
ranging from 3 to 9 years when compared with
those who did not have interstitial lung abnormalities. This was seen
after adjustment was made for smoking, chronic obstructive pulmonary disease (COPD)
, cancer and other co-existing conditions.
AGES-Reykjavik study was the only study to assess causes of death and the
higher rate of mortality seen in this group could be explained by a higher rate
of death due to respiratory disease
(13%), particularly pulmonary fibrosis.
Putnam and his associates
reported in the journal JAMA
pattern of abnormalities may be an important risk factor for death in older
populations, rather than being merely a precursor to more advanced fibrosis.
The authors stated, "Given
the ability to treat more advanced stages of pulmonary fibrosis, future
clinical trials attempting to reduce the overall mortality associated with
pulmonary fibrosis should consider including early stages of the disease."
They noted that while additional
studies were needed to confirm the findings and to determine the risk factors
for interstitial lung abnormalities and the events that lead to the death of
commented, "Although the survival rate of people with idiopathic pulmonary
fibrosis (IPF) appears to have increased slightly in recent years, median
survival times after diagnosis is 3 to 5 years, which is worse than that of
most malignancies. Given the other correlations between IPF and interstitial
lung abnormalities, we hypothesized that the presence of interstitial lung
abnormalities would be associated with an increased rate of mortality."
of the study could have significant implications for clinical practice and
research, however requires further investigation.