Audit of antihypertensive treatment in patients with renal failure

Recently, intensified antihypertensive treatment has been recommended for patients with proteinuric renal disease, and a target blood pressure of 125/75 mmHg has been proposed.

In a retrospective crossectional study, all consecutive patients with renal disease and reduced GFR seen in the renal outpatient clinic Heidelberg during a specified time period were analysed. Physicians administered antihypertensive agents according to their clinical judgment aware of recent recommendations, but without structured guidelines. The aims of the study were: (i) to monitor achieved blood pressure (clinic measurement, self measurement, ambulatory BP measurement); (ii) to monitor the number of antihypertensive medications required; and (iii) to analyse the factors which determine achieved blood pressure and the number of antihypertensive agents required.

There were 201 non-transplanted patients, median age 60 years (range 20-86), 131 male, 70 female, median S-creatinine 2.33 mg/dl (1.4-10.9). Fifty-two of the patients had diabetes, 41 GN, 18 ADPKD, 17 vasculitis, seven reflux nephropathy, three analgesic nephropathy and 63 other or unknown renal diseases. When the patients had originally been referred to the renal clinic, median clinic BP had been 160 mmHg systolic (104-260) and 95 mmHg diastolic (65-160). Under nephrological care, achieved clinic systolic (140; 90-190) and diastolic BP values (85; 45-130) were significantly (P<0.0001) lower. Achieved BP was slightly (r=0.23, P<0.05) correlated with age, was not significantly different between genders, and was not correlated to proteinuria, serum creatinine, renal disease or BMI. Average self measured BP values were not different from systolic and diastolic clinic BP values. Ambulatory BP values, however, were significantly (P<0.0001) lower, e.g. daytime systolic BP 133 mmHg (107-171), diastolic 82 mmHg (65-97). A night-time decrease of BP > or = 15% was seen in 18/25 patients only. The median number of antihypertensive classes required was 3 (range 1-7) in non-diabetic and 3.5 (1-7) in diabetic patients, respectively. The number of antihypertensive classes was independent of serum creatinine, BMI or proteinuria, but was significantly (P<0.01) higher in males (4; 1-7) than in females (3; 1-6) and correlated to age (r=27, P<0.01).

The study (i) illustrates the difficulty to achieve recommended target BP in patients with renal failure, (ii) shows remarkably little white coat effect on clinic blood pressure, (iii) illustrates the value of ambulatory blood pressure measurement and (iv) documents the importance of multidrug antihypertensive treatment in patients with renal failure.