The prognosis of pulmonary sarcoidosis in Finland and Hokkaido, Japan. A comparative five-year study of biopsy-proven cases

Background and aim of the study: The frequency and clinical picture of sarc oidosis are different in Finland and Hokkaido, Japan. The aim of this study was to compare the normalisation rate of chest radiographic changes in pat ients with biopsy-proven sarcoidosis. Method: The chest radiographs of 437 Finnish and 457 Japanese patients were used and, for the purpose of this st udy, double-checked in order to make sure that the interpretations were ide ntical. On a yearly basis the radiographs were classified as normalised, im proved, unchanged or deteriorated. Results: Normalisation of chest radiogra phs occurred in 73% of the Japanese and 40% of the Finnish patients. The di fference between the two series was significant (p<0.001). Gender, young ag e, presence or absence of symptoms or extrapulmonary lesions at diagnosis o r treatment with corticosteroids did not influence the difference between t he two series. Of the 191 Finnish and 309 Japanese patients with initial st age I disease a normal chest radiograph was obtained in 47% of the Finnish and 76% of the Japanese patients (p<0.001), despite the fact that the Finni sh series included patients with erythema nodosum, who had a 59% normalisat ion rate. Of the 186 Finnish and 125 Japanese patients with initial stage I I disease, normalisation of the chest radiographs was seen in 36% of the Fi nnish and in 73% of the Japanese patients (p<0.001). No difference in norma lisation rate was seen between stage III patients. Conclusion: The prognosi s of pulmonary sarcoidosis in Japanese patients in Hokkaido is significantl y better than that in Finland defined as normalisation rate of the chest ra diographs.