Aim: To investigate the association between angiotensin-converting enzyme gene I/D polymorphism and diabetic nephropathy (DN) in patients with Type 2 diabetes mellitus (DM) taking into consideration the known duration of DM.
Methods: Cross-sectional study with 982 patients categorized according to urinary albumin excretion (UAE) into normoalbuminuria (UAE < 20 microg/min or < 17 mg/l, 24-h timed urine or spot random sterile urine, respectively), incipient DN (UAE 20-199 microg/min or 17-174 mg/l) and overt DN (UAE > 200 microg/min or > 174 mg/l or dialysis). Patients were further grouped regarding presence of the D allele (DD/ID vs. II) and DM duration (< or = 10 years or > 10 years).
Results: Incipient DN was diagnosed in 17.3% (n = 170), and 20.7% (n = 203) had overt DN (macroalbuminuria, n = 129; dialysis, n = 74). Genotype distribution (DD/ID/II) was similar in patients with incipient (49/92/29) or overt DN (77/89/37) if compared with patients without DN (181/308/120, P = 0.172). In patients with DM < or = 10 years, having the D allele (DD/ID) resulted in an odds ratio (OR) of 2.66 (95% CI: 1.12-6.58, P = 0.015) for incipient DN, and 3.19 (95% CI: 1.18-9.30, P = 0.012) for overt DN. In patients with longer DM duration, the D allele did not increase the risk for incipient (OR 0.68, 95% CI 0.36-1.29, P = 0.206) or overt DN (OR 0.67, 95% CI 0.39-1.17, P = 0.138).
Conclusion: The DD/ID genotypes were associated with incipient or overt DN in patients with DM < or = 10 years.