Diabetic nephropathy in 27,805 children, adolescents, and adults with type 1 diabetes: effect of diabetes duration, A1C, hypertension, dyslipidemia, diabetes onset, and sex.
OBJECTIVE
To give an up-to-date profile of nephropathy and the involvement of risk factors in a large, prospective cohort of patients with type 1 diabetes and largely pediatric and adolescent onset of disease.


METHODS
A total of 27,805 patients from the nationwide, prospective German Diabetes Documentation System survey were included in the present analysis. Inclusion criteria were at least two documented urine analyses with identical classification. Urine analyses, treatment regimens, diabetes complications, and risk factors were recorded prospectively. Baseline characteristics were age at diagnosis 9.94 years (median [interquartile range 5.8-14.3]), age at last visit 16.34 years (12.5-22.2), and follow-up time 2.5 years (0.43-5.3). Cumulative incidence of nephropathy was tested by Kaplan-Meier analysis and association with risk factors by logistic regression.


RESULTS
Nephropathy was classified as normal in 26,605, microalbuminuric in 919, macroalbuminuric in 78, and end-stage renal disease (ESRD) in 203 patients. After calculated diabetes duration of 40 years, 25.4% (95% CI 22.3-28.3) had microalbuminuria and 9.4% (8.3-11.4) had macroalbuminuria or ESRD. Risk factors for microalbuminuria were diabetes duration (odds ratio 1.033, P < 0.0001), A1C (1.13, P < 0.0001), LDL cholesterol (1.003, P < 0.0074), and blood pressure (1.008, P < 0.0074), while childhood diabetes onset (1.011, P < 0.0001) was protective. Male sex was associated with the development of macroalbuminuria.


CONCLUSIONS
Diabetes duration, A1C, dyslipidemia, blood pressure, and male sex were identified as risk factors for nephropathy. Therefore, besides the best possible metabolic control, early diagnosis and prompt treatment of dyslipidemia and hypertension is mandatory in patients with type 1 diabetes.
Raile
Klemens
K
Department of Pediatric Endocrinology and Diabetes, Charité Children's Hospital, Augustenburger Platz 1, 13353 Berlin, Germany. klemens.raile@charite.de
Galler
Angela
A
Hofer
Sabine
S
Herbst
Antje
A
Dunstheimer
Desiree
D
Busch
Petra
P
Holl
Reinhard W
RW
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000419:Albuminuria / Q000453:epidemiology; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D003925:Diabetic Angiopathies / Q000453:epidemiology; D003928:Diabetic Nephropathies / Q000453:epidemiology*; D050171:Dyslipidemias / Q000453:epidemiology; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D008297:Male; D012016:Reference Values; D012307:Risk Factors; D012727:Sex Characteristics; D012907:Smoking; D013997:Time Factors