Variable renal trajectories may complicate type 2 diabetes prescribing
medwireNews: People with type 2 diabetes experience an overall decline in renal function over time, but there is substantial variation among individuals, with some seeing an improvement in estimated glomerular filtration rate (eGFR), researchers report.
“This highlights the difficulty when prescribing glucose-lowering therapies based on a single measurement of renal function, as well as the importance of regular monitoring of renal function in people with [type 2 diabetes],” say Abby Teboth (Boehringer Ingelheim Ltd, Bracknell, UK) and study co-authors.
The study included 7766 people from a UK primary care database who were newly diagnosed with type 2 diabetes between 2009 and 2011. In all, 32.8% of patients had a baseline eGFR of at least 90 mL/min per 1.73m2, while the majority (50.2%) had an eGFR between 60 and 89 mL/min per 1.73 m2. A total of 12.4%, 4.0%, and 0.6% of the cohort had measurements of 45–59, 30–44, and 15–29 mL/min per 1.73 m2, respectively.
Over 5 years of follow-up, average eGFR across the study population declined by 0.44 mL/min per 1.73 m2 each year, with a mean increase of 0.80 mL/min per 1.73 m2 seen in the first year, followed by a steady decline of 0.75 mL/min per 1.73 m2 thereafter.
However, the pattern of eGFR change varied across the different categories of baseline renal function. For example, individuals in the highest eGFR category experienced a consistent decline over the study period, while those in the middle categories had an initial increase over the first year, followed by a steady decline. By contrast, people with the worst kidney function at baseline experienced an overall increase in eGFR of 1.85 mL/min per 1.73 m2 annually.
“[P]eople with worse renal function (eGFR<60 mL/min/1.73m2) seemed to show the greatest variation, both from the overall study population and from their baseline eGFR,” observe the researchers.
Teboth and colleagues note that overall, 21.3% of patients had moved to a lower eGFR category by the 5-year follow-up, and 20.0% had moved to a higher category, with patients moving between categories 1.5 times on average.
When data from individual people were analyzed separately, the team demonstrated that 56.7% of the study population experienced a decrease in renal function over 5 years, with the remainder having an increase or no change in eGFR. A total of 15.8% of patients experienced an increase of 10 mL/min per 1.73 m2 or more.
Taken together, these findings demonstrate “considerable variation within clinical categories of renal function and at individual level,” summarize the study authors in Diabetes, Obesity and Metabolism.
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