Contemporary renal disease progression rates have slowed in type 1 diabetes
medwireNews: Current rates of renal disease progression in people with type 1 diabetes are lower than historic estimates, UK study data show.
However, Helen Colhoun (University of Edinburgh, UK) and colleagues found that there was wide variation in decline among the 5777 individuals they studied, “with an important minority of people exhibiting a rapid loss of eGFR [estimated glomerular filtration rate].”
These people typically have “clustering of other complications and are more likely to have nonlinear trajectories” of progression, the researchers write in Diabetologia.
At baseline, the cohort, which was representative of the adult population with type 1 diabetes in Scotland, had median age of 44.1 years and a median diabetes duration of 20.9 years.
The prevalence of eGFR levels of above 90 (CKD stage G1), 60–90 (stage G2), 30–60 (stage G3), 15–30 (stage G4), and at or below 15 mL/min per 1.73 m2 (end-stage renal disease [ESRD]) was 64.0%, 29.3%, 5.4%, 0.6%, and 0.7%, respectively.
In addition, 8.6% of participants were microalbuminuric (urinary albumin/creatinine ratio [ACR]= 3.39–33.9 mg/mol) and 3.0% were macroalbuminuric (>33.9 mg/mmol), and the researchers note that 65.3% of participants with CKD stage G3 and 28.6% of those at stage G4 had no history of albuminuria.
During 11.6 years of follow-up, the median annual rate of eGFR decline “was modest” at −1.3 mL/min per 1.73 m2, Colhoun et al observed.
They found that although the majority of individuals had stable or slowly declining eGFR, 10.0% experienced a moderate rate of annual decline of 3.0–5.0 mL/min per 1.73 m2 and 4.1% had rapid decline of more than 5.0 mL/min per 1.73 m2 per year.
These declining patients were significantly more likely to have cardiovascular disease (CVD) and retinopathy than people with stable eGFR, at odds ratios of 1.95 and 1.30, respectively, despite the eGFR being greater than 60 mL/min per 1.73 m2 in the majority.
In an attempt to predict which people will be rapid decliners, the researchers tested a number of different models. They found that the most accurate one was a linear model that included age, sex, diabetes duration, current eGFR and ACR, glycated hemoglobin, prior CVD status, prior eGFR slope, and the 2-year mean of eGFR.
“In particular, using mean eGFR over 2 years gave a substantial improvement in predicting future eGFR because single eGFR readings are quite noisy and variable,” the researchers remark.
Colhoun and team conclude that “although progressive loss of renal function is less common than in the past, it remains very important.”
“In this regard we note that decliners constitute a group already at elevated risk for CVD and retinopathy even at young ages […] emphasizing the importance of their early identification.”
They add that such identification “could be improved using a formal risk prediction model or at least encouraging clinicians to consider means of recent eGFR measurements and prior slopes alongside the most current eGFR.”
By Laura Cowen
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