Characteristics of the nocturnal desaturation waveform pattern of SpO2 in COPD patients: an observational study

Respiratory Research

Table 2 Association of the intermittent pattern with clinical data

	Desaturation with intermittent pattern N = 108	Desaturation without intermittent pattern N = 20	P value
Male/female	98/10	18/2	1.00
Age, years	71 [68–75]	71.5 [67.3–75.8]	0.888
BMI	22.6 [20.3–24.6]	22.8 [21.2–24.3]	0.825
Daytime SpO_2, %	97 [96–98]	97 [96–97.8]	0.528
Smoking history, pack-years	50 [40–80]	60 [45.5–67.5]	0.737
%FVC, %	90.1 [78.0–99.2]	91.4 [76.6–102.7]	0.646
%FEV₁, %	63.1 [50.6–76.6]	58.2 [46.0–79]	0.871
FEV₁/FVC, %	60.2 [50–66]	60.3 [51.7–67.0]	0.970
PM-AHI	19.5 [13.1–41.9]	5.7 [3.5–9.3]	< 0.0001*
CT90, %	2.9 [0.72–13.2]	0.445 [0.025–6.7]	0.024*
Lowest SpO₂, %	83.5 [77.3–87]	88 [86–90.5]	< 0.0001*
ODI	7.4 [4.0–11.8]	2.0 [1.3–3.3]	< 0.0001*
Hypoxic burden, (%min)/h	13.3 [4.3–33.5]	2.2 [0.92–8.6]	< 0.0001*

Desaturation with the intermittent pattern consists of I, P + I, S + I and S + P + I. Desaturation without the intermittent pattern consists of S, P and S + P. S: Sustained, P: Periodic, I: Intermittent
PM-AHI, CT90%, Lowest SpO₂, ODI and Hypoxic burden were obtained from a pulse oximeter performed during night
The data are presented as median [interquartile range]. *P < 0.05
BMI body mass index, FVC forced vital capacity, FEV₁ forced expiratory volume in 1 s, PM-AHI apnoea-hypopnea index from portable monitor, CT90 cumulative percentage time at SpO₂ below 90%

ISSN: 1465-993X