Diffuse idiopathic skeletal hyperostosis in smokers is associated with Restrictive Spirometry Pattern: an analysis in the COPDGene cohort
Abstract
Objective Diffuse idiopathic skeletal hyperostosis (DISH) is a condition characterized by bony proliferation at sites of tendinous and ligamentous insertions in the spine. Spinal mobility is reduced in DISH and may affect movement in the thorax, potentially leading to restrictive pulmonary function. This study investigated whether DISH is associated with restrictive spirometry pattern (RSP) in former and current smokers.
Methods 1,784 participants with complete post-bronchodilator spirometry who did not meet spirometric criteria for COPD at time of enrollment in the COPDGene study were included in this study. Subjects were classified as RSP if they had Forced Expiratory volume in one second \(FEV1) to Forced Vital Capacity (FVC) ratio > 0.7 with an FVC<80%. CT scans were scored for the presence of DISH in accordance with the Resnick criteria. Chest CT measures of interstitial and alveolar lung disease, clinical symptoms, health surveys, and six-minute walking distance (6MWD) were recorded. Uni- and multivariable analyses were performed to test the association of DISH with RSP.
Results DISH was present in 236 subjects (13.2%). RSP was twice as common in participants with DISH (N=90/236, 38.1%) compared to those without DISH (N=301/1548, 19.4%), p<0.001. In multivariable analysis DISH was significantly associated with RSP (OR 1.78; 95%CI; 1.22-2.60; p=0.003) after adjusting for potential confounders. The RSP group with and without DISH had significantly worse spirometry, dyspnea, SGRQ score, BODE and SF-36.
Conclusion In heavy smokers with an FEV1/FVC ratio > 0.70, DISH is associated with RSP after adjustment for intrinsic and extrinsic causes of restrictive lung function.