EFFECTS OF COMBINED UPPER AND LOWER RESPIRATORY SYMPTOMS ON PULMONARY FUNCTION AND EXERCISE TOLERANCE AMONG DYSPNEIC VETERANS

Abstract

TOPIC: Occupational and Environmental Lung Diseases TYPE: Original Investigations PURPOSE: The unified airway model underscores the interdependence of the upper and lower respiratory tracts and has been described in the context of occupational exposure. Upper and lower airway conditions appear to be increasing in prevalence among military veterans of our most recent conflicts [Operation Enduring Freedom (OEF), Operation Iraqi Freedom (OIF), and Operation New Dawn (OND)] post-deployment, but have not been thoroughly examined in combination. Here, we examine the impact of combined upper (URS) and lower respiratory symptoms (LRS) on pulmonary function and exercise tolerance among veterans referred for chronic dyspnea. METHODS: Eighty-one deployed veterans referred to our War Related Illness and Injury Study Center within the Department of Veterans Affairs, presented with URS or LRS (URS/LRS; n= 41) or both (URS+LRS; n = 40). The presence of URS and LRS was determined via the Sino-Nasal Outcome Test (average score ≥ 2) and standardized questionnaire (cough, wheeze or shortness of breath ≥ 2 days·wk1), respectively. All veterans completed complete pulmonary function testing (PFT). Exercise tolerance and physical health-related functioning was assessed via maximal cardiopulmonary exercise testing and questionnaire (VR-36 PCS). Between-group differences and effect sizes were assessed via unpaired t-tests and Hedges' d, respectively. RESULTS: Groups (URS/LRS, URS+LRS) were similar for sex: male (33, 35), female (8, 5); age (42.5±10.7, 44.9±8.3 years); body mass index (32.5±5.2, 32.3±7.0 kg/m2); tobacco history (13.7±7.8, 12.7±11.0 pack years); and deployment length (13.7±7.8, 12.7±11.0 months). Time from deployment to clinical evaluation was greater in veterans with URS+LRS (10.7±6.8, 14.5±8.6; p = 0.03, d = -0.49 [-0.94, -0.04]). PFTs were similar between groups with exception for residual volume/total lung capacity ratio (RV/TLC) (23.4±9.4, 28.9±9.9; p = 0.01, d = -0.56 [-1.01, -0.11]); Forced Vital Capacity (FVC%) (97.9±12.7, 88.4±18.5; p < 0.01, d = 0.59 [0.15, 1.04]); and Forced Expiratory Volume (FEV1%) (95.0±15.3, 86.5±20.5, p = 0.04, d = 0.47 [0.03, 0.91]). Peak exercise capacity (VO2%: 88.8±18.2, 77.6±17.0; p < 0.01, d = 0.63 [0.46, 1.43]) and physical-health related functioning (PCS: 34.2±9.2, 25.9±7.9, d = 0.95 [0.46, 1.43]). CONCLUSIONS: Combined URS and LRS represent a major cause of morbidity in OEF/OIF/OND veterans. Those with combined URS+LRS were found to have higher RV/TLC and lower FVC% and FEV1%. Those with URS+LRS also had worse exercise tolerance and overall quality of life than those with only LRS/URS, indicative of significant disease burden. CLINICAL IMPLICATIONS: Although there is limited data of the effect of URS+LRS on veterans, our findings support the idea that those with combined disease have a significant impact on pulmonary function and quality of life than those with either disease. DISCLOSURES: No relevant relationships by Andrew Berman, source=Web Response No relevant relationships by Michael Falvo, source=Web Response No relevant relationships by Nisha Jani, source=Web Response No relevant relationships by Thomas Ng, source=Web Response No relevant relationships by Anays Sotolongo, source=Web Response No relevant relationships by Jennifer Therkorn, source=Web Response