The new leadership triad will build on the innovative work of Drs . Mark Dransfield and Ed Blalock who led the Center for nearly 15 years as medical and scientific director respectively . Under their leadership , the Center grew from three extramurally funded investigators to over 20 , and its research portfolio grew from less than $ 5 million to more than $ 20 million in extramural funding .
MIcheal Wells , M . D ., Amit Gaggar , M . D ., Ph . D ., and Gabriella Oates , Ph . D .
Photography : Steve Wood
Founded by Emeritus Professor William Bailey in 1986 , the UAB
Lung Health Center pursues key program areas spanning interstitial lung disease , critical care , lung transplantation , thoracic oncology , pneumonia , asthma , and COPD .
Bhatt Establishes Diagnostic Thresholds for Airflow Metric by Andy Currie
Considerable controversy exists on the best methods to diagnose airflow obstruction . Most of the discrete ratio thresholds used to define airflow obstruction are insensitive to early and mild disease . Although several efforts have been made to develop other measures for detection of airflow obstruction , these have not resulted in clinically useful measures with sufficient discrimination from normal . Additionally , demographics like age can influence currently-used airflow obstruction measures , complicating diagnostic threshold selection for airflow obstruction .
To combat this , a research team led by Surya Bhatt , M . D . proposed a new airflow obstruction metric Parameter D . In the current work , Dr . Bhatt and team evaluated the influence of demographics on Parameter D and showed that this new measure is minimally influenced by most demographics . In addition , the team reported new diagnostic thresholds for parameter D based on normal population that could aid in the early identification of more individuals with airflow obstruction .
Bhatt ? s research team analyzed the spirometry data of normal subjects enrolled in the 2007-8 , 2009-10 and 2011-12 NHANES cohorts and calculated Parameter D using the expiratory volume-time curve . Relationships between demographics and lung function ( FEV1 , FEV1 / FVC , and Parameter D ) were assessed using generalized linear models in NHANES and UK Biobank . Based on concordance between the lower-limit-of-normal ( LLN ) for FEV1 / FVC and the Parameter D threshold , four groups were found : Normal ( no airflow obstruction by either criterion ), D + COPD ( positive by Parameter D only ), D-COPD ( positive by LLN only ), and COPD ( positive by both criteria ). Any associations with structural lung disease , exacerbations , and mortality were assessed using multivariable analyses .
The variance of Parameter D explained by each demographic feature is very low , in contrast to FEV1 . FEV1 is significantly influenced by body size and its correlates of height , sex , and race . Age-related loss of lung elasticity also has a negative impact on FEV1 . In contrast , it is plausible that in the case of Parameter D , the rate of volume change reflects proportions of the preceding segments of the curve , meaning the impact of lung size is negligible . The FEV1 / FVC ratio , by including lung size in the denominator , is minimally influenced by height but decreases substantially with advancing age . Parameter D , in contrast , is not influenced by age .
Based on the frequency distribution of Parameter D in a representative healthy community dwelling population , the research team also discovered a threshold that results in the identification of additional individuals with a substantial amount of structural lung disease and respiratory symptoms . Over 25 % of those with airflow obstruction identified by Parameter D alone were found to have airflow obstruction by traditional criteria 5 years later . When this is compared 8 % of normal , this suggests that this metric can also find airflow obstruction earlier .
Surya Bhatt , M . D . Photography : Steve Wood with
PULMONARY , ALLERGY , AND CRITICAL CARE MEDICINE