Value of blood pressure self-monitoring as a predictor of progression of diabetic nephropathy

Objective To determine the impact of self-monitoring of blood pressure Values (BPS) as compared with office blood pressure measurements (BPO) on the progression of diabetic nephropathy. Design Long-term, follow-up cohort study. Subjects and methods Hypertensive, type 1 diabetic patients with overt diabetic nephropathy were investigated. Patients initially participated in a hypertension treatment and teaching programme including extensive advice on blood pressure self-monitoring. Self-monitoring and office blood pressure values were continuously assessed during the entire follow-up period. Progression of diabetic nephropathy over the study period was individually assessed as the mean decline of glomerular filtration rate (GFR) per patient per year. Baseline and follow-up parameters were included in stepwise multiple regression analyses with the decline of GFR per year as the dependent variable. Results Seventy-seven type 1 diabetic patients (37 women, 40 men) were followed for a mean period of 6.2 +/- 2.8 years (mean +/- SD; range 2-12) resulting in a total of 481 patient-years. During the follow-up period, mean BPO decreased from 166/95 at baseline to 154/89 mmHg during follow-up, and mean BPS fell from 159/93 to 138/83 mmHg. The mean decline of GFR was 4.1 +/- 5.6 ml/min per year. Loss of kidney function was significantly correlated with proteinuria, blood pressure and glycosylated haemoglobin values. In the multiple regression analyses, BPS predicted the loss of renal function better than BPO (R-2 = 0.52 versus 0.42). The simple correlation between BPS and GFR decline was higher compared to BPO and GFR (r = -0.42; P < 0.0001 versus -0.33; P < 0.004). Conclusion Blood pressure self-monitoring values are a better predictor of progression of diabetic nephropathy when compared with office blood pressure measurements. J Hypertens 1999, 17:597-601 (C) Lippincott Williams & Wilkins.