Overview

In health, blood pressure (BP) falls at night by >10% compared with day-time values. This natural dipping pattern is important as without it there is an increased risk of cardiovascular disease (CVD). Recent evidence suggests that chronotherapy (taking anti-hypertensive medication at bedtime instead of in the morning) may enhance nocturnal BP dipping and reduce the risk of CVD events. There is therefore an urgent need to characterise diurnal BP patterns in patients who may be at risk of reduced nocturnal dipping in order to maximise protective therapy in all those who would benefit. Similarly, it has previously been demonstrated that increased arterial stiffness is associated with increased CVD risk, however little is known about whether loss of diurnal variations in arterial stiffness confer addition risk. Kidney disease is independently associated with increased CVD events, but the exact makeup of this risk is not clear. Within this heterogenous cohort several very distinct groups exist including those with acute kidney injury (AKI), chronic kidney disease (CKD), inflammatory conditions like small vessel vasculitis (SVV), and those who have either donated or received a kidney transplant. Diurnal BP and arterial stiffness patterns within these patient groups are not well characterised. The investigators will recruit patients at increased risk of CVD from the Royal Infirmary of Edinburgh Renal and Vasculitis Clinics. Participants will undergo 24-hour ambulatory BP and arterial stiffness measurement in conjunction with day- and night-time blood and urine sampling on two separate occasions. This study aims to characterise diurnal patterns of BP and arterial stiffness in patients at increased risk of CVD and compare findings with healthy controls. In doing so, the investigators aim to allow more targeted CVD risk reduction strategies and improve long-term patient outcomes.

Eligibility

Inclusion Criteria:

• Patients will be eligible to take part in the study if they attend NHS Lothian inpatient or outpatient services and can be classified as being at increased risk of CVD. This will include, but is not limited to, the following subgroups:
  1. CKD as defined by the Kidney Disease Outcome Quality Initiative (K/DOQI) classification
  2. AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) classification
  3. Small vessel vasculitis
  4. Kidney transplant recipient
  5. Kidney donor We will also recruit a healthy control group from the community.

Exclusion Criteria:

1. Age <18 years and >90 years
2. Lack of ability to provide informed consent