Reference values of impulse oscillometry (IOS) for healthy Indian adults

Reference equations for oscillometry and their differences among populations: a systematic scoping review

“…The construction of reference equations was different between included studies ( table 3 ). In seven of the 10 studies [ 15 – 18 , 21 , 22 , 24 ], either oscillometric indices or demographic variables were mathematically transformed (logarithmic, inverse or exponential function). While almost all studies referred to linear regression models for oscillometric indices, S chulz et al .…”

“…Intriguingly, reference equations developed in the Latin American population [21] showed significant homogeneity with the standard reference [16]. In the case of X 5 , while there was significant homogeneity between the equations of the reference study [16] and equations of other studies [17,[19][20][21][22][23][24], equations developed by MOITRA et al [15] and BROWN et al [18] were markedly different from the standard reference [16]. The equations developed for AX were significantly different from the standard reference, except for one study [24] that showed low-to-moderate agreement with the reference study.…”

“…One study [20] considered the variable weight in resistance (R 5 and R 20 ) equations for men but not women, while another study reported weight only in equations for women. While all included equations showed a negative trend in total airway resistance (R 5 ) with increasing height, MOITRA et al [15] demonstrated a positive trend for both sexes (i.e. R 5 increases with height) (figure 3).…”

“…The accuracy of PFTs in assessing respiratory health is based on validated reference values [1,2,11]. However, unlike globally accepted reference equations for spirometry [12], reference equations for oscillometric indices are diverse and were developed from country-specific populations [13][14][15]. At present, the oscillometric reference equations developed by OOSTVEEN et al [16] are most commonly used as the standard model for adults.…”

“…And third, participants in that study were recruited from four different countries; despite having the same ethnicity, possible anthropometric heterogeneity between populations could have a significant influence on oscillometric measurements, and this has not been properly addressed. Moreover, despite the availability of some population-specific reference equations [15][16][17][18][19][20][21][22][23][24], most of these equations are either based on a relatively small sample size [15,16,18,19,21,22,24], include an inappropriate sample selection (e.g. current or former smokers) [22,24] or are mathematically complex [23].…”