The applicability of the gland/wall ratio (Reid-Index) to clinicopathological correlation studies

We studied at necropsy the bronchi of 49 subjects whose lung function has been measured during life. In each case the glands were examined in three bronchi by measuring the gland/wall ratio (Reid-Index) and by point-counting. The results of the two methods were compared: the data of the gland/wall ratio were normally distributed while those of the volume density established by point-counting were not. Gland/wall ratio and volume density of glands correlated moderately (RSp = 0.524). The function between them was not linear, in contrast with that between gland/wall ratio and gland thickness. The stereological background of these functions is discussed. In 34 subjects without restrictive lung disease FEV1 correlated inversely with the volume density of glands (RSp = -0.396), but not with the gland/wall ratio (Reid-Index)(RSp = -0.243). This discrepancy probably results from the different distribution of the data obtained by the two methods and from the non-linear function between them. These findings indicate that the gland/wall ratio (Reid-Index) is less applicable to clinicopathological correlations than the volume density of glands established by point-counting.