Natural history and risk factors for microalbuminuria in adolescents with type 1 diabetes: a longitudinal study.
OBJECTIVE
To describe the natural history and risk factors for persistent microalbuminuria in children and adolescents with type 1 diabetes followed for up to 15 years.


METHODS
This study contained a longitudinal cohort of 972 patients; analysis of baseline risk factors was performed using logistic regression and predictors over time using survival analysis. Albumin excretion rate was measured on three consecutive timed overnight urine collections on at least two occasions. Normoalbuminuria was defined as a median albumin excretion rate < 7.5 microg/min, borderline microalbuminuria as 7.5-20 microg/min, and microalbuminuria as 20-200 microg/min. Microalbuminuria was further classified as persistent if its duration was >12 months. Median age was 12.7 years (interquartile range 11.5-14.4) and diabetes duration 6.5 years (4.1-9.3) at first assessment, and median follow-up was 6.2 years (range 1-15.3).


RESULTS
The incidence of persistent microalbuminuria was 4.6 (95% CI 3.3-6.1) per 1,000 patient-years. Predictors of persistent microalbuminuria from the first assessment using multiple logistic regression were high cholesterol (odds ratio 2.2 [95% CI 1.2-4.0]) and borderline microalbuminuria (2.5 [1.2-5.2]). Predictors using Cox regression were HbA(1c) (hazard ratio 1.4 [95% CI 1.1-1.7]), age at diagnosis (1.2 [1.1-1.3]), obesity (3.6 [0.8-15.5]), and insulin dose (2.7 [1.0-7.5]).


CONCLUSIONS
Children and adolescents with type 1 diabetes who have borderline microalbuminuria are more than twice as likely to develop persistent microalbuminuria. In addition to poor glycemic control, clinical markers of insulin resistance were associated with an increased risk of microalbuminuria.
Stone
Monique L
ML
Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Hawkesbury Road, Westmead, Sydney, Australia.
Craig
Maria E
ME
Chan
Albert K
AK
Lee
Jenny W
JW
Verge
Charles F
CF
Donaghue
Kim C
KC
D000293:Adolescent; D000419:Albuminuria / Q000150:complications / Q000473:pathology / Q000652:urine*; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D018450:Disease Progression; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D016015:Logistic Models; D008137:Longitudinal Studies; D012307:Risk Factors; D016019:Survival Analysis