Table 4.

Studies assessing respiratory event–related metrics.

Study	Study Size/Type	Type of PSG (Level 1 or 2)	Sex (% male)	Mean BMI (kg/m2)	Mean AHI (/h)	Mean Age (years)	% OSA Participants	Metric	Outcome	Results
Goh (2018)53 Singapore	821/Retro	1	67	28	28	48	100	Apneic and Hypopneic load	ESS	Linear regression analysis found age (P < .001), apnea load (P = .005), REM (P = .021) and stage 1 sleep duration (P = .042) were independent factors correlated to ESS.
Butler (2019)44 USA	5712/Retro of Pros	1	48	28.1	13.8	63.3	67	Respiratory event duration	All-cause mortality	Individuals with the shortest-duration events had a significantly increased hazard ratio for all-cause mortality
Kim (2021)31 USA	2055/Cross-sectional	1	46	28.7	14.8	68.4	Not referenced	Duty cycle and IFL	Hypertension	Higher duty cycle and IFL were associated with lower BP
Mediano (2007)54 Spain	40/Retro	1	100	32	61	50	100	Apnea duration	EDS	Longer apnea duration can be a determinant of excessive daytime sleepiness in OSA patients

AHI = apnea hypopnea index, BMI = body mass index, BP = blood pressure, EDS = excessive daytime sleepiness, ESS = Epworth Sleepiness Scale, IFL = inspiratory flow limitation, ODI = oxygen desaturation index, OSA = obstructive sleep apnea, Pros = prospective, PSG = polysomnography, RDI = respiratory disturbance index, REM = rapid eye movement, Retro = Retrospective, Retro of Pros = retrospective analysis of prospective study, SD = standard deviation.