A critical analysis of sarcoidosis incidence assessment.

Valid sarcoidosis incidence assessment is contingent on access to medical care, thoroughness of reportage, assiduity of radiographic interpretation, employment and health care screening policies, misclassification, and population ethnicity. To diminish ambiguity and foster inter-population comparison, the term "sarcoidosis incidence" must be modified to convey the methodology employed in compiling the numerator. In age-delimited cohorts, valid comparison to population incidence requires age adjustment due to the age-dependency of incidence. The "true incidence" of sarcoidosis is a notional concept: more than 90% of cases are subclinical and radiographically inevident. Occupational causal inference based on incidence differential vs. populations has been undermined by methodological differences in ascertainment and computation.

Mortality of intrathoracic sarcoidosis in referral vs population-based settings: influence of stage, ethnicity, and corticosteroid therapy.

STUDY OBJECTIVES: To compare the sarcoidosis mortality in referral settings (RS) and population-based settings (PS), and to identify the contribution of stage, ethnicity, and corticosteroid therapy (CST) to their disparate outcomes. DESIGN: All observational studies identified in a MEDLINE search and bibliographic review published in the English language since 1960 dealing with the course and prognosis of sarcoidosis in large, unsorted, adult, ambulatory RS and PS providing long-term follow-up were reviewed and subjected to meta-analysis. MEASUREMENTS AND RESULTS: Sarcoidosis mortality in RS (4.8%), in which 17% of patients had the most unfavorable prognosis as judged by stage (stage III), was 10-fold that reported in PS (0.5%), in which 11% of patients were identified at this stage. The magnitude of this disparity could not be accounted for solely by adverse selection, as indicated by stage or by ethnicity. Patients in RS received CST with sevenfold the frequency of PS, and its provision was highly correlated with stage-normalized mortality. CONCLUSION: The prognosis of patients with intrathoracic sarcoidosis in PS is far more favorable than that obtained in RS. Sarcoidosis mortality is largely independent of ethnicity. The possibility cannot be excluded that excessive employment of CST may unfavorably influence the long-term course of the disease in some individuals.