Abstract 4058: A longitudinal Study of Risk Factors for the Incident Abnormal Albuminuria in Diabetic American Indians: The Strong Heart Study
Objective: Using longitudinal analysis method to identify significant risk factors for incident abnormal albuminuria (urinary albumin/creatinine ratio [UACR] ≥ 30 mg/g) in diabetic American Indians in the Strong Heart Study (SHS).
Population and Methods: Among 931 diabetic participants aged 45 to 74 years with normal albuminuria (UACR<30 mg/g) at the 1st SHS examination (1989 − 91), 504 remained with normal albuminuria, 249 developed abnormal albuminuria, and 181 were missing UACR (either died or did not attend the examination) at the 2nd examination (1993–5). Among 504 diabetic participants with normal albuminuria at the 2nd examination, 315 remained with normal albuminuria, 99 developed abnormal albuminuria, and 90 were missing UACR at the 3rd examination (1997–9). The generalized estimating equation method for dichotomous outcomes in longitudinal studies was used to identify risk factors for incident abnormal albuminuria. Unstructured correlation structure was specified to account for related observations from different examinations for participants. In the model, risk factors (independent) measurements from an examination for participants with normal albuminuria and abnormal albuminuria (outcome) from the next examination (averaged four years from the previous examination) will be used to investigate independent predictions of risk factors including age, gender, study center, HDL and LDL cholesterol, triglycerides, BMI, systolic blood pressure (SBP), anti-hypertensive, smoking, alcohol consumption, HbA1c, diabetes treatment and duration, serum creatinine, previous UACR in normal range.
Results: Incident abnormal albuminuria was predicted by previous UACR [Odds ratio (OR)=1.51, 95% CI: 1.23–1.85 per doubling of UACR, p<0.001], female gender (OR=1.58, CI: 1.09–2.28, p=0.015), HbA1c (OR=1.05, CI: 1.02–1.09 per 0.5%, p=0.003), serum creatinine (OR=1.30, CI: 1.09–1.56 per 0.2 mg/dl, p=0.005), and SBP (OR=1.06, CI: 1.01–1.10 per 5 mm Hg, p=0.015).
Conclusion: In middle-aged to elderly diabetic American Indians, UACR in the normal range, female gender, HbA1c, serum creatinine, and SBP independently predict subsequent abnormal albuminuria.
Key words: longitudinal analysis, incidence, abnormal albuminuria, risk factor.