Clinical Course of Sarcoidosis in World Trade Center-Exposed Firefighters

Abstract

Background: Sarcoidosis is believed to represent a genetically primed, abnormal immune response to an antigen exposure or inflammatory trigger, with both genetic and environmental factors playing a role in disease onset and phenotypic expression. In a population of firefighters with post-World Trade Center (WTC) 9/11/2001 (9/11) sarcoidosis, we have a unique opportunity to describe the clinical course of incident sarcoidosis during the 15 years postexposure and, on average, 8 years following diagnosis.

Methods: Among the WTC-exposed cohort, 74 firefighters with post-9/11 sarcoidosis were identified through medical records review. A total of 59 were enrolled in follow-up studies. For each participant, the World Association of Sarcoidosis and Other Granulomatous Diseases organ assessment tool was used to categorize the sarcoidosis involvement of each organ system at time of diagnosis and at follow-up.

Results: The incidence of sarcoidosis post-9/11 was 25 per 100,000. Radiographic resolution of intrathoracic involvement occurred in 24 (45%) subjects. Lung function for nearly all subjects was within normal limits. Extrathoracic involvement increased, most prominently joints (15%) and cardiac (16%) involvement. There was no evidence of calcium dysmetabolism. Few subjects had ocular (5%) or skin (2%) involvement, and none had beryllium sensitization. Most (76%) subjects did not receive any treatment.

Conclusions: Extrathoracic disease was more prevalent in WTC-related sarcoidosis than reported for patients with sarcoidosis without WTC exposure or for other exposure-related granulomatous diseases (beryllium disease and hypersensitivity pneumonitis). Cardiac involvement would have been missed if evaluation stopped after ECG, 48-h recordings, and echocardiogram. Our results also support the need for advanced cardiac screening in asymptomatic patients with strenuous, stressful, public safety occupations, given the potential fatality of a missed diagnosis.

Keywords: World Trade Center; clinical course; firefighters; sarcoidosis.

Figure 1

Pulmonary function at diagnosis and follow-up. Average percent predicted pulmonary function among cases who had complete pulmonary data at diagnosis and follow-up: FEV₁ and FVC (n = 57); Dlco (n = 41); and FRC (n = 30). All 59 cases had complete data at follow-up. Differences in pulmonary function metrics between diagnosis and follow-up were not statistically significant. Dlco = carbon monoxide diffusing capacity; FRC = functional residual capacity.

Figure 2

Clinical course of sarcoidosis organ involvement at diagnosis and follow-up. Other organs include: eye, spleen, skin, liver, kidney, ears/nose/throat, and calcium. All 59 cases had complete data at both diagnosis and follow-up for all organs with the following exceptions: chest CT scan (n = 54); eye (n = 58); spleen (n = 57); cardiac (n = 57); and ears/nose/throat (n = 57). Serum calcium levels were assessed at diagnosis, and serum calcium and Vitamin D levels were assessed at follow-up.

Figure 3

Cardiac assessments at follow-up examination for sarcoidosis cases. Cardiac evaluation at follow-up demonstrating how many cases would have been missed if the evaluation stopped after an earlier test result was unremarkable. For example, an unremarkable ECG would have missed seven cases with abnormal continuous cardiac recording and six cases with abnormal cardiac MRI. The same would have occurred if the evaluation stopped after both an unremarkable ECG and echocardiogram. An abnormal ECG with an unremarkable echocardiogram would have missed six cases with abnormal continuous cardiac recording and two cases with abnormal cardiac MRI. ^aOne case missing an echocardiogram. ^bTwo cases missing cardiac recordings. One case missing an echocardiogram, had an unremarkable 48-h cardiac recording (not shown) and a missing cardiac MRI. ^cFour cases missing cardiac MRIs.