Ambulatory blood pressure monitoring and progression in patients with IgA nephropathy

Background. Hypertension is a recognized marker of poor prognosis in IgA ne phropathy. Methods. The present study investigated the prevalence of white-coat hypert ension, the diurnal rhythm of blood pressure (BP), the effectiveness of ant ihypertensive drug therapy, and the effect of the above on the progression of the kidney disease in IgA nephropathy. One hundred twenty-six IgA nephro pathy patients were selected consecutively for 24-h ambulatory blood pressu re monitoring (ABPM). Fifty-five patients were normotensive and 71 were tre ated hypertensives. Their antihypertensive drugs were angiotensin-convertin g enzyme inhibitors (ACEI) alone or in combination with calcium-channel blo ckers (CCB). Results. The mean night-time BP of normotensives (108 +/- 9/67 +/- 6 mmHg) was significantly lower than their day-time BP (125 +/- 8/82 +/- 7 mmHg, P < 0.05). There was no significant difference between the mean day-time and night-time BP in hypertensive patients (125 +/- 9/82 +/- 7 mmHg vs 128 +/- 10/85 +/- 9 mmHg). The circadian variation of BP was preserved ('dippers') in 82% of the normotensive and 7% of the hypertensive patients (P < 0.001). There were 10 'white-coat hypertensives' among the patients classified as normotensives with ABPM (mean office blood pressure 149 +/- 7/96 +/- 8 mmHg , 24-h blood pressure 127 +/- 6/83 +/- 5 mmHg, P < 0.05) and 14 among treat ed hypertensives (mean office BP 152 +/- 8/98 +/- 6 mmHg, 24-h BP 130 +/- 4 /85 +/- 8 mmHg, P < 0.05). There was no difference in mean day-time BP amon g normotensive and treated hypertensive patients (125 +/- 8/81 +/- 5 mmHg v s 128 +/- 10/85 +/- 9 mmHg). Hypertensives had significantly higher night-t ime BP (125 +/- 9/85 +/- 9 mmHg) than normotensives (108 +/- 9/67 +/- 6 mmH g, P < 0.001). There was no difference in serum creatinine levels among the different groups at the time of the ABPM. However, thirty-six +/- 4.1 mont hs after the ABPM, hypertensive patients (n = 52) had higher serum creatini ne levels (124 +/- 32 mu mol/l) than at the time of the ABPM (101 +/- 28 mu mol/l). The serum creatinine of normotensive patients (n = 43) did not cha nge during the follow-up period. 'Non-dipper' normotensives (n = 10) had si gnificantly higher serum creatinine levels at the end of the follow-up peri od than at its beginning (106 +/- 17 mu mol/l vs 89 +/- 18 mu mol/l, P < 0. 05). There was no increase in serum creatinine of 'dipper' normotensives. T he mean serum creatinine of 'white-coat hypertensives' was significantly hi gher at the end of the study period than at its beginning. Conclusions. There is no diurnal blood pressure variation in most of the hy pertensive IgA nephropathy patients. ACEI and CCB treatment have better eff ect on day-time than night-time hypertension. The lack of the circadian rhy thm and 'white-coat hypertension' seems to accelerate the progression of Ig A nephropathy.