Table 2

Baseline and follow-up BP of subjects by baseline OSA severity

BP parametersNormalPrimary snoringMild OSAModerate-to-severe OSAP for trend*
n=98n=49n=75n=21
Daytime SBP (mm Hg)
 Baseline†112±10112±7113±8114±70.35
 ≥95th percentile, n (%)0 (0)0 (0)1 (1.7)0 (0)0.38
 Follow-up‡115±9116±10117±10118±80.076
 ≥135 mm Hg, n (%)1 (1.0)3 (6.1)3 (4.0)0 (0.0)0.59
Daytime DBP (mm Hg)
 Baseline†71±673±672±673±40.20
 ≥95th percentile, n (%)1 (1.3%)2 (6.1)2 (3.4%)0 (0.0)0.81
 Follow-up‡72±673±673±672±50.68
 ≥85 mm Hg, n (%)2 (2.0)3 (6.1)4 (5.3)0 (0.0)0.67
Night-time SBP (mm Hg)
 Baseline†99±1098±6101±8106±11§0.011
 ≥95th percentile, n (%)10 (13.2)0 (0.0)6 (10.3)5 (29.4)0.36
 Follow-up‡103±9104±9104±9111±10§0.007
 ≥120 mm Hg, n (%)3 (3.1)1 (2.0)4 (5.4)6 (28.6)§0.001
Night-time DBP (mm Hg)
 Baseline†59±658±559±562±60.19
 ≥95th percentile, n (%)12 (15.8)2 (6.1)8 (13.8)5 (29.4)0.47
 Follow-up‡62±663±762±664±70.45
 ≥70 mm Hg, n (%)9 (9.3)8 (16.3)9 (12.2)2 (9.5)0.73
Any hypertension, n (%)
 Baseline†17 (22.4)3 (9.1)12 (20.7)7 (41.2)0.33
 Follow-up‡11 (11.3)11 (22.4)14 (18.9)6 (28.6)0.053
SBP nocturnal dipping (%)
 Baseline†11.4±5.012.8±4.99.9±5.77.6±7.4§0.009
 Follow-up‡10.1±4.89.6±6.010.5±5.46.3±5.7§0.15
SBP non-dipping, n (%)
 Baseline†29 (38.2)9 (27.3)25 (43.1)11 (64.7)0.097
 Follow-up‡53 (54.6)27 (55.1)35 (47.3)17 (81.0)0.48
DBP nocturnal dipping (%)
 Baseline†17.3±6.719.7±7.417.8±5.815.8±7.20.78
 Follow-up‡14.5±6.414.2±7.515.2±6.311.9±8.00.60
DBP non-dipping, n (%)
 Baseline†10 (13.2)2 (6.1%6 (10.3)3 (17.6)0.97
 Follow-up‡22 (22.7)16 (32.7)14 (18.9)7 (33.3)0.84
  • *P values obtained from linear contrast tests and linear-by-linear association tests for continuous and categorical data, respectively.

  • †59 missing.

  • ‡2 missing.

  • §P <0.05 after Bonferroni adjustment, compared with the normal group.

  • BP, Blood Pressure; DBP, Diastolic Blood Pressure; OSA, Obstructive Sleep Apnoea; SBP, Systolic Blood Pressure.