Pulmonary sarcoidosis: differences in lung function change over time

Introduction Given the heterogeneity of sarcoidosis, predicting disease course of patients remains a challenge. Our aim was to determine whether the 3-year change in pulmonary function differed between pulmonary function phenotypes and whether there were differential longitudinal changes by race and sex. Methods We identified individuals seen between 2005 and 2015 with a confirmed diagnosis of sarcoidosis who had at least two pulmonary function test measurements within 3 years of entry into the cohort. For each individual, spirometry, diffusion capacity, Charlson Comorbidity Index, sarcoidosis organ involvement, diagnosis duration, tobacco use, race, sex, age and medications were recorded. We compared changes in pulmonary function by type of pulmonary function phenotype and for demographic groups. Results Of 291 individuals, 59% (173) were female and 54% (156) were black. Individuals with restrictive pulmonary function phenotype had significantly greater 3-year rate of decline of FVC% (forced vital capacity) predicted and FEV₁% (forced expiratory volume in 1 s) predicted course when compared with normal phenotype. We identified a subset of individuals in the cohort, highest decliners, who had a median 3-year FVC decline of 156 mL. Black individuals had worse pulmonary function at entry into the cohort measured by FVC% predicted, FEV₁% predicted and diffusing capacity for carbon monoxide % predicted compared with white individuals. Black individuals’ pulmonary function remained stable or declined over time, whereas white individuals’ pulmonary function improved over time. There were no sex differences in rate of change in any pulmonary function parameters. Summary We found significant differences in 3-year change in pulmonary function among pulmonary function phenotypes and races, but no difference between sexes.