Audit of 24-hour ambulatory blood pressure vs clinic measurements for adjusting ant-hypertensive treatment

Author(s): Raju J, Kennedy D and S Ramachandran

Institute: Good Hope Hospital, Heart of England Foundation Trust, Biochemistry, Sutton Coldfield

We have audited Clinic blood pressure (BP) data for 32 patients obtained whilst attending diabetic and lipid clinics at Good Hope Hospital and compared this with 24 hour ambulatory blood pressure (24hABP) readings obtained afterward. The aim was to determine whether anti-hypertensive management decisions would alter if based on 24hABP rather than clinic BP. Data was collected from clinic notes including antihypertensive medications, most recent HbA1c, serum creatinine and lipid concentrations. ABP monitoring was carried out using the 'Tracker NIBP2 Oscillometric ambulatory BP recorder'. The mean systolic ABP over 24 hours was 131mm Hg (n=32 range 107-157) significantly lower than the mean clinic BP of 163 mm Hg (range 138-220). A significant difference between mean clinic BP and mean 24hABP of 32 was observed (n=32 range 1-79 p<0.001 Wilcoxon test).

The clinical data of 32 patients with clinic BP or 24 hour average ABP was given to 5 doctors within diabetes team to determine whether or not they would advise initiating or adding further anti-hypertensive agents. Based on the data provided by the doctors it was clear that considerably reduced numbers of patients would require addition of antihypertensive agents to control their blood pressure based on the 24 hr BP monitoring basis as compared to clinical BP measurement. This has obvious advantages for the patients as well as potentially significant cost saving for the NHS.