Introduction: Chronic respiratory diseases are an im-portant cause of morbimortality, with a high prevalen-ce of cardiovascular comorbidities. Population studies have shown that airflow limitation, as measured by spi-rometry, is a predictor of cardiovascular risk and futu-re high blood pressure. The circadian rhythm of blood pressure (BP) is important for risk stratification, with particular attention currently given to nighttime blood pressure and its variability as predictors of target-organ damage, cardiovascular events, and mortality.

Objective: To analyze the blood pressure circadian profile in a cohort of patients with chronic respirato-ry diseases, addressed to the respiratory rehabilitation program.

Methods: The study included 41 patients with chronic respiratory diseases, admitted to Iași Respiratory Re-habilitation Clinic, in January-July 2018, for the respi-ratory rehabilitation program. All patients underwent 24-hours non-invasive ambulatory blood pressure (ABPM) and heart rate (HR) monitoring. The data were statistically analyzed and have been identified: the 24-hours mean blood pressure, mean daytime and nighttime systolic and diastolic BP, HR, the pulse pre-ssure (PP), standard deviation (SD), and the nighttime blood pressure dipping pattern, according to current guidelines. Subsequently, these values were compared between high-risk night-time group versus those with a low-risk profile.

Results: T he study included 16 women and 25 men, mean age 63.7 ± 11.64 years and BMI of 29.94 ± 5.45 kg/ m². Circadian rhythm analysis revealed the following BP dipping patterns: 17 dippers, 17 non-dippers, 6 ri-sers, and none with an extreme-dipper pattern, and mean HR/24-h of 67.58 bpm. The mean BP values were 131.65/77.07mmHg/24 hours, 133.97/77.07mmHg daytime, and 122.75/71.31mmHg nighttime. The vari-ability of the systolic BP (SBP) has been reflected by SD values: 25.51 ± 16,94mmHg (24 hours), 25.65 ± 17,56mmHg daytime, and 15.65 ± 14,42mmHg nightti-me. Between the groups with a different risk profile, there were significant differences regarding nocturnal SBP and DBP (p<0.05), as well as nocturnal medium arterial pressure (MAP) (p<0.05) but not in terms of daytime mean values or 24-hour values.

Conclusions: The analysis of the circadian rhythm of blood pressure in patients with chronic respiratory diseases demonstrated mean values corresponding to nocturnal hypertension and abnormally high variabi-lity of BP, despite the daytime and overall blood pressu-re control. Non-dipper and riser were the predominant patterns most commonly associated with the target-or-gans damage and the occurrence of fatal and non-fatal cardiovascular events. This blood pressure profile must draw attention to the residual risk in the management of hypertension in this population of patients, with the-rapeutic and prognostic implications.