Three-Year Study Links Continuous Glucose Monitoring to Long-Term Blood Sugar Control and Potential Kidney Marker Benefits
A new observational study published in JAMA Network Open suggests that sustained use of real-time continuous glucose monitoring (rtCGM) may offer long-term benefits for high-risk adults managing type 2 diabetes. While previous short-term randomized clinical trials have highlighted the advantages of these devices in daily glucose management, this multi-year evaluation explored whether sustained wear translates into lasting glycemic control and improved kidney health markers.
Chronically elevated blood sugar levels are known to cause progressive damage to the kidneys over time. To better understand the long-term impact of technology-assisted management, researchers evaluated electronic health records from Kaiser Permanente Northern California, utilizing a target trial emulation approach. The analysis focused on adults with type 2 diabetes who had poor glycemic control or a history of severe hypoglycemia, comparing individuals who initiated rtCGM with matched control groups who did not use the technology.
Tracking Glycemic Control and Kidney Markers Over Time
The study followed participants for up to 36 months, examining primary outcomes that included hemoglobin A1c (HbA1c) levels, urinary albumin-creatinine ratio (UACR), and estimated glomerular filtration rate (eGFR). UACR measures urinary albumin relative to creatinine to help detect potential kidney damage, while eGFR evaluates how effectively the kidneys filter blood.
At the start of the investigation, participants initiating rtCGM typically presented with more complex clinical profiles, including longer diabetes durations, higher comorbidity burdens, and lower baseline kidney function compared to controls. However, statistical weighting was applied to balance these baseline differences across the study groups.
The findings revealed that sustained rtCGM use was associated with rapid and persistent improvements in blood sugar control. One year following baseline, the weighted mean HbA1c level among rtCGM users was 7.83%, compared to 8.93% in the control group—a difference of 1.10 percentage points. These improvements endured throughout the follow-up period, maintaining a difference of 0.75 percentage points at the three-year mark.
Examining Long-Term Kidney Health Impacts
Regarding kidney health markers, researchers observed no statistically significant differences in UACR between the groups at baseline, or at the one- and two-year evaluations. By the three-year mark, however, sustained rtCGM use was associated with a lower mean UACR, with values of 153 mg/g in the rtCGM group versus 278 mg/g in controls.
Despite this later reduction in albuminuria among participants who maintained monitoring, the study did not find evidence that sustained rtCGM preserves overall kidney filtration function. Weighted eGFR estimates showed no significant preservation of filtration capacity by the end of the three-year period. Furthermore, the observational design and substantial participant discontinuation—with many users dropping out or crossing over between monitoring groups—introduced limitations that researchers noted could affect the causal interpretation of longer-term outcomes.
Next Steps for Research
The authors concluded that while sustained rtCGM use correlates with durable glycemic improvements and potential reductions in albuminuria among high-risk patients, the data do not currently establish that the technology prevents the progression of diabetic kidney disease. Longer-term randomized controlled trials are required to confirm these sustained glycemic benefits and to determine whether rtCGM can definitively preserve kidney function.
Funding for the study was provided by Dexcom alongside various healthcare and research organizations, though the authors confirmed that study funders had no role in the design, data analysis, or publication decisions.
Source: News-Medical.net
