Retinal and renal complications in patients with a mutation of mitochondrial DNA at position 3,243 (maternally inherited diabetes and deafness). A case-control study

Aims/hypothesis We assessed the prevalence and determinants of retinal and renal complications in patients with maternally inherited diabetes and deafness (MIDD). Methods This was a multicentre prospective study comparing the prevalence of retinopathy and renal disease in 74 patients with MIDD and 134 control patients matched for sex, age and clinical presentation at onset of diabetes, duration of diabetes and current treatment. Comparisons were adjusted for HbA₁c and hypertension. Results In MIDD patients, HbA₁c (7.6 ± 1.6 vs 8.5 ± 2.0%, p < 0.002), systolic blood pressure (126.6 ± 16.2 vs 133.1 ± 17.3 mmHg, p < 0.007) and prevalence of hypertension (33.8 vs 64.2%, p < 0.0001) were lower than in control patients. Prevalence of diabetic retinopathy was 3.7-fold lower in MIDD patients (6/74, 8 vs 40/134, 29.6%, p < 0.0001). Differences between groups remained significant after adjustment for hypertension, systolic blood pressure and HbA₁c. In MIDD, urinary albumin excretion (314.8 vs 80.1 mg/24 h, p = 0.035) and creatinine plasma levels (103.5 vs 82.2 μmol/l, p = 0.0178) were higher and GFR was lower. Impaired renal function (GFR