Resolution rate of pulmonary sarcoidosis and its related factors in a Japanese population.

BACKGROUND AND OBJECTIVE: A number of previous studies have reported on the rate of resolution of pulmonary sarcoidosis and its associated factors. However, most of the studies were conducted several decades ago and no similar surveys have been conducted in recent years. The aim of this study was to evaluate the rate of resolution of pulmonary sarcoidosis and its related factors in recently diagnosed patients, and to compare the results with those from previous studies.

METHODS: This study included 306 patients who had been newly diagnosed with pulmonary sarcoidosis between 2000 and 2009 in Sapporo, Japan. Chest radiographical findings were assessed at the initial visit and at the 2- or 5-year observation points. The rates of resolution on chest radiographs and the association with clinical manifestations were evaluated.

RESULTS: The resolution rates were 17.9% at the 2-year and 29.9% at the 5-year observation point. These rates were lower than those reported in the earlier surveys. Younger subjects (aged <40 years) showed resolution more often (P < 0.05). The absence of extra-pulmonary organ involvement was associated with resolution at 5 years (P < 0.05).

CONCLUSION: The clinical course of pulmonary sarcoidosis may be changing, showing a tendency not to resolve. At least in part, this may be due to the ageing of the Japanese population.