WHITE COAT HYPERTENSION IN NIDDM PATIENTS WITH AND WITHOUT INCIPIENT AND OVERT DIABETIC NEPHROPATHY

OBJECTIVE - Early data have suggested a high prevalence of white coat hypertension (similar to 50%) in NIDDM patients. To study this phenome non further, we determined the prevalence of white coat hypertension i n NIDDM patients with normo- or microalbuminuria or with diabetic neph ropathy RESEARCH DESIGN AND METHODS - Three groups of hypertensive NID DM patients (repeated clinic blood pressure >140/90 mmHg or antihypert ensive treatment) attending the Steno Diabetes Center were investigate d in a cross-sectional study. Group 1 had normoalbuminuria (a urinary albumin excretion [UAE] rate <30 mg/24 h, n = 30, age 61 +/- 7 [mean /- SD] years, 20 men), group 2 had microalbuminuria (UAE rate 30-300 m g/24 h, n = 51, age 55 +/- 7 years, 35 men), and group 3 had diabetic nephropathy (UAE rate >300 mg/24h, n = 47, 62 +/- 7 years, 36 men). If given, all previous antihypertensive medication was withdrawn at leas t 2 weeks before the study (48%). The prevalence of white coat hyperte nsion (clinic hypertension with normal blood pressure values at home) was determined by comparison of clinic blood pressure (Hawksley Random sphygmomanometer) and the ambulatory daytime (7:00 A.M. to 11:00 P.M. ) blood pressure (A&D TM2420). By applying established criteria, white coat hypertension was confirmed if daytime blood pressure was <135/85 mmHg. RESULTS - The clinic blood pressure was 155/86 (SE 3/2) mmHg, 1 56/89 (2/1) mmHg, and 171/90 (3/2) mmHg in group 1, 2, and 3, respecti vely (P < 0.05 comparing group 3 with groups 1 and 2). The prevalence of white coat hypertension was significantly higher in group I as comp ared with groups 2 and 3, 23% (95% CI 10-42) vs. 8% (2-19) and 9% (2-2 0) (P < 0.05), with no difference between the latter two groups. CONCL USIONS - The prevalence of white coat hypertension in normoalbuminuric NIDDM patients resembles that observed in nondiabetic subjects with e ssential hypertension, whereas the prevalence is significantly lower i n NIDDM patients with incipient or overt diabetic nephropathy, suggest ing a difference between primary and secondary hypertension.