Abstract
OBJECTIVE: To investigate the risk factors for the development of persistent microalbuminuria in insulin dependent diabetic patients. DESIGN: Four year follow up of a cohort of diabetic patients. SETTING: Outpatient departments of teaching and district general hospitals in England. SUBJECTS: 148 non-microalbuminuric, non-hypertensive insulin dependent diabetic patients. MAIN OUTCOME MEASURES: Urinary albumin excretion rate and arterial blood pressure. RESULTS: 137 patients completed four year follow up, of whom 11 developed persistent microalbumin-uria (albumin excretion rate > or = 30 micrograms/min on at least two consecutive occasions), giving a cumulative frequency of 8%. 103 remained normoalbuminuric and 23 exhibited intermittent microalbuminuria. At baseline the persistent microalbuminuric group had had significantly raised blood pressure (mean 137.9 (SD 14.9)/82.3 (7.6) v 123.5 (13.2)/72.8 (9.1) mm Hg), glycated haemoglobin concentration 10.4% (2.0%) v 8-9% (2.0%), and albumin excretion rate (median (interquartile range) 17.5 (13.0-22.3) v 4.8 (3.7-6.7) micrograms/min) (p < 0.05 for all) compared with the normo-albuminuric group. Blood pressure and glycated haemoglobin remained significantly higher in the persistent microalbuminuric group throughout the study (p < 0.05). Multiple regression analysis showed initial albumin excretion rate, blood pressure, and smoking to be significant determinants of persistent microalbuminuria (p < 0.02). CONCLUSION: In insulin dependent diabetic patients with poor glucose control, which may initially increase albumin excretion rate, an early rise of arterial pressure and smoking are implicated in the development of persistent microalbuminuria.