Risk factors for decline in renal function among young adults with type 1 diabetes.

Aims: To investigate risk factors for declining renal function among subjects with type-1-diabetes.

Methods: Observational study based on data from the diabetes registry DPV. 4424 type-1-diabetes subjects aged ≥18 years, age at onset <18 years were identified. Modification of Diet in Renal Disease (MDRD) equation was used to estimate glomerular filtration rate (eGFR). Annual rate of renal decline was estimated for each patient using hierarchic linear regression models. Additional regression models were fitted to adjust for covariates.

Results: Median age was 26 [Q1; Q3: 21; 39] years. Annual decline of renal function was -1.22 (95% CI: -1.50; -0.94) ml/min/1.73 m. At baseline, higher eGFR was related to more rapid decline compared to impaired or reduced eGFR (GFR ≥ 90: -2.06 (-2.35; -1.76), 60 ≤ GFR < 90: 0.45 (0.08; 0.81), GFR < 60: 0.52 (-0.24; 1.29) ml/min/1.73 m, p < 0.01). During follow-up, the highest decline was associated with reduced renal function, whereas the lowest decline was related to normal kidney function (p < 0.01). Poor metabolic control (p = 0.04), hypertension (p < 0.01) and albuminuria (p = 0.03) were associated with more rapid loss of kidney function. No difference was observed among insulin regimen.

Conclusion: Among this large type-1-diabetes cohort, more rapid loss of kidney function was related to higher baseline eGFR, log-term worse metabolic control and diabetic comorbidities.