Premium
Comparison of apnoea–hypopnoea index and oxygen desaturation index when identifying obstructive sleep apnoea using type‐4 sleep studies
Author(s) -
Senaratna Chamara V.,
Lowe Adrian,
Perret Jennifer L.,
Lodge Caroline,
Bowatte Gayan,
Abramson Michael J.,
Thompson Bruce R.,
Hamilton Garun,
Dharmage Shyamali C.
Publication year - 2019
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/jsr.12804
Subject(s) - concordance , medicine , quartile , polysomnography , sleep (system call) , body mass index , cohort , sleep study , apnea , confidence interval , computer science , operating system
Summary The concordance of different indices from type‐4 sleep studies in diagnosing and categorising the severity of obstructive sleep apnoea is not known. This is a critical gap as type‐4 sleep studies are used to diagnose obstructive sleep apnoea in some settings. Therefore, we aimed to determine the concordance between flow‐based apnoea–hypopnoea index ( AHI flow50% ) and oxygen desaturation index ( ODI 3% ) by measuring them concurrently. Using a random sub‐sample of 296 from a population‐based cohort who underwent two‐channel type‐4 sleep studies, we assessed the concordance between AHI flow50% and ODI 3% . We compared the prevalence of obstructive sleep apnoea of various severities as identified by the two methods, and determined their concordance using coefficient Kappa(κ). Participants were aged (mean ± SD) 53 ± 0.9 years (48% male). The body mass index was 28.8 ± 5.2 kg m −2 and neck circumference was 37.4 ± 3.9 cm. The median AHI flow50% was 5 (inter‐quartile range 2, 10) and median ODI 3% was 9 (inter‐quartile range 4, 15). The o bstructive sleep apnoea prevalence reported using AHI flow50% was significantly lower than that reported using ODI 3% at all severity thresholds. Although 90% of those with moderate–severe obstructive sleep apnoea classified using AHI flow50% were identified by using ODI 3% , only 46% of those with moderate–severe obstructive sleep apnoea classified using ODI 3% were identified by AHI flow50% . The overall concordance between AHI flow50% and ODI 3% in diagnosing and classifying the severity of obstructive sleep apnoea was only fair (κ = 0.32), better for males (κ = 0.42 [95% confidence interval 0.32–0.57] versus 0.22 [95% confidence interval 0.09–0.31]), and lowest for those with a body mass index ≥ 35 (κ = 0.11). In conclusion, ODI 3% and AHI flow50% from type‐4 sleep studies are at least moderately discordant. Until further evidence is available, the use of ODI 3% as the measure of choice for type‐4 sleep studies is recommended cautiously.