Objective To investigate the detection rate, influencing factors, and 24-hour ambulatory blood pressure monitoring (ABPM) characteristics of orthostatic hypotension (OH) in middle-aged and elderly inpatients.

Methods A retrospective study was conducted, consecutively enrolling 366 middle-aged and elderly inpatients who completed orthostatic blood pressure measurement and ABPM. OH was defined as a decrease in systolic blood pressure (SBP) ≥ 20 mmHg or diastolic blood pressure (DBP) ≥ 10 mmHg within 3 minutes after standing from the supine position; patients were divided into OH group (n = 73) and non-OH group (n = 293). According to the definition of a decrease in SBP ≥ 15% or DBP ≥ 5% within 3 minutes after standing, patients were further divided into OH_Ratio group (n = 93) and non-OH_Ratio group (n = 273). Clinical characteristics and ABPM parameters were compared between groups. Multivariate logistic regression was used to analyze factors influencing OH and OH_Ratio.

Results  The detection rate of OH in middle-aged and elderly inpatients was 19.95% (73/366), and that of OH_Ratio was 25.41% (93/366). Compared with the non-OH group, the OH group was older, had higher detection rates of hypertension, diabetes mellitus, and carotid-femoral pulse wave velocity (cfPWV) ≥ 10 m/s, and had higher usage rates of diuretics, β-blockers, and antiplatelet agents (all P＜0.05). ABPM data showed that the 24-hour, daytime, and nighttime mean DBPs in the OH group were significantly lower than those in the non-OH group (all P＜0.05), whereas no significant differences were observed in mean SBP, blood pressure circadian rhythm, or nocturnal blood pressure dipping rate between the two groups (all P＞0.05). Similar results were found in the OH_Ratio group. Multivariate logistic regression analysis indicated that age ≥ 60 years (OR = 2.003, 95%CI: 1.024 to 3.915), cfPWV ≥ 10 m/s (OR = 2.123, 95%CI: 1.158 to 3.893), and diuretic use (OR = 2.497, 95%CI: 1.033 to 6.036) increased the risk of OH, whereas each 1 mmHg increase in daytime mean DBP was associated with a 4.3% reduction in OH risk (OR = 0.957, 95%CI: 0.930 to 0.985). For OH_Ratio, cfPWV ≥ 10 m/s (OR = 2.752, 95%CI: 1.571 to 4.821) and age ≥ 60 years (OR = 2.095, 95%CI: 1.136 to 3.867) increased the risk, while higher daytime mean DBP decreased the risk (OR = 0.957, 95%CI: 0.932 to 0.983).

Conclusion The detection rates of OH and OH_Ratio are relatively high in middle-aged and elderly inpatients. Age ≥ 60 years and cfPWV ≥ 10 m/s increase the risk of OH and OH_Ratio, whereas the increase in daytime mean DBP reduces the risk.