1. Microalbumuria in non-diabetic elderly subjects is predictive of vascular disease and mortality, and related to levels of blood pressure.
2. This study was designed to examine whether more restricted periods of urine collection retained the relation to the prevailing level of blood pressure and successfully identified subjects with microalbuminura.
3. Fifty elderly subjects (aged over 60 years) made two consecutive 24-h urine collections for measurement of urinary albumin excretion, divided between daytime and night-time periods. Thirty-three subjects also provided a random ‘spot’ urine sample. Clinic and 24-h ambulatory blood pressure were also recorded.
4. Median 24-h urinary albumin excretion was 15.75 mg; 17 subjects had microalbuminuria. The median 24-h albumin—creatinine ratio was 1.91 mg/mmol. A threshold albumin—creatinine ratio of ≧ 3.0 mg/mmol in a random urine sample predicted microalbuminura with 92% sensitivity and 90% specificity. Alternatively, threshold values of 2.5 mg/mmol for men and 4.5 mg/mmol for women in an overnight urine collection predicted microalbuminuria with 88% sensitivity and 100% specificity.
5. The closest relation between albumin—creatinine ratio and blood pressure was that between spot albumin—creatinine ratio and clinic systolic blood pressure (r = 0.64, P < 0.001). Albumin—creatinine ratio was generally related to clinic systolic blood pressure, diastolic blood pressure and ambulatory systolic blood pressure. Microalbuminuric subjects had significantly higher levels of clinic and ambulatory systolic blood pressure than non-microalbuminuric subjects.
6. Microalbuminuria in the elderly is most closely related to clinic systolic blood pressure. Screening for microalbuminuria in the elderly can usefully be performed by the measurement of albumin—creatinine ratio in a random urine sample, with a threshold of ≧ 3.0 mg/mmol.