Table 2. Correlation coefficients between nocturnal SBP fall and clinical factors.

	Medical hypertension treatment (-) (n = 117)		All (n = 303)
Variables	r	P	r	P
Age	-0.097	0.30	-0.098	0.08
Gender (male = 1, female = 0)	-0.131	0.17	-0.036	0.52
Body mass index	0.121	0.20	-0.009	0.88
Current smoking (yes = 1. no = 0)	0.060	0.53	0.038	0.51
Cardiovascular disease history (yes = 1. no = 0)	-0.097	0.31	-0.029	0.61
Medical hypertension treatment
Calcium-channel blocker (yes = 1. no = 0)	-	-	0.014	0.81
ACE inhibitor or ARB (yes = 1. no = 0)	-	-	-0.124	0.03
α or β blocker (yes = 1. no = 0)	-	-	-0.058	0.31
Diuretic agent (yes = 1. no = 0)	-	-	-0.070	0.22
Presence of dyslipidemia (yes = 1. no = 0)	0.129	0.17	0.066	0.25
Presence of diabetes mellitus (yes = 1. no = 0)	-0.142	0.13	-0.060	0.30
LVEF	-0.005	0.96	0.003	0.96
eGFR	0.105	0.28	0.129	0.03
ln(AHI)	-0.031	0.75	-0.112	0.06
Urinary sodium	-0.156	0.11	-0.032	0.59
Endocirne and Metabolic parameters
Plasma aldosterone	0.069	0.48	0.048	0.42
Plasma renin activity	0.072	0.47	0.075	0.21
Urinary cortisol	0.011	0.91	0.003	0.96
HOMA	0.070	0.47	-0.021	0.92
ln(BDNF)	0.126	0.19	0.168	<0.01
Heart rate variability
ln(SDNN)	-0.005	0.95	0.112	0.06
ln(CVRR)	0.025	0.79	0.132	0.03
ln(SDANN5)	-0.009	0.92	0.128	0.03

Pearson's correlation coefficients were performed. The parameters of AHI, BDNF and heart rate variability were natural logarithm-transformed (ln) to achieve normal distribution. ACE nenotes angiotensin converting enzyme, ARB angiotensin receprot blocker, LVEF left ventricular ejection fraction, eGFR estimated glomerular filtration rate, AHI apnea hypopnea index, SBP systolic blood pressure, HOMA homeostasis model assessment as an index of insulin resistance, BDNF brain-derived neurotrophic factor, SDNN standard deviation of the NN(RR) interval, CVRR coefficient of variation R-R interval and SDANN5 standard deviation of the average of NN intervals for each 5 min period.