Table 4

Baseline values and changes in polysomnographic parameters

Baseline, mean (SD)/median (IQR)Intra-group differences, mean (95% CI)p Value of inter-group differences
NIVControlNIVControlUnadjustedAdjusted
TST, hours5.3 (1.7)5.4 (1.5)0.15 (1 to 0.6)0.1 (0.5 to 0.7)NS
Sleep efficiency77 (29)79 (24)−5.4 (−15 to 4.6)3.5 (−5.1 to 12)NS
% Non-REM light sleep67 (27)63 (24)−6.2 (−15 to 2.3)−4 (−12 to 3.7)NS
% Non-REM deep sleep18 (17)23 (18)4.6 (−3.2 to 12)1.6 (−6.4 to 9.6)NS
% REM sleep8.7 (8.9)13 (15)5.6 (−0.9 to 12)3.3 (−3 to 9.6)NS
Arousal index25 (20)22 (18)10 (14 to6.2)‡−0.3 (−2.9 to 2.3)0.0000.000
AHI14 (8.9)15 (7.8)11 (15 to7.1)‡0.1 (−2.7 to 2.8)0.0000.000
DI18 (27)19 (16)19 (25 to12)‡−0.4 (−4.6:3.8)0.0000.000
Mean SaO288 (8)87 (5)6 (4.3 to 7.7)‡0.4 (−0.5 to 1.4)0.0000.000
%TST <9082 (58)69 (79)36 (46 to25)‡−5.7 (−15 to 2)0.0000.002
  • Median (IQR) values are shown in italic.

  • Bold type indicates statistical significance.

  • p Values of intra-group differences (2 months − baseline): ‡p<0.001.

  • p Values of inter-group differences unadjusted or adjusted by basic adjustment (baseline values of the variable analysed and age, gender, BMI and AHI).

  • AHI, apnoea–hypopnoea index; BMI, body mass index; DI, desaturation index; %TST <90, percentage of TST below 90% of oxygen saturation; NIV, non-invasive ventilation; REM, rapid eye movement; SaO2, arterial oxygen saturation; TST, total sleep time.