Lifestyle Intervention Programs Show Durable Renal-Function Benefits Even with Weight Regain

Osama Hamdy, MD, PhD (Joslin)

Intensive lifestyle intervention (ILI) programs can lead to long-term benefits in estimated glomerular filtration rate (eGFR), cholesterol, and serum creatinine even if patients are unable to maintain their weight loss, according to new research.

However, the study also showed that patients who regained the weight lost during the program saw rapid deterioration in hemoglobin A1c and serum triglycerides, but not systolic blood pressure (SBP).

Obesity is a major contributing factor to rising rates of diabetes, and patients who develop diabetes and are obese are at a higher risk of complications such as kidney disease. As such, these patients are often recommended for weight-loss programs or, in some cases, surgical intervention.

Investigators from the Joslin Diabetes Center at Harvard Medical School wanted to find out what would happen to real-world patients who took a 12-week ILI program called Why WAIT? (Weight Achievement and Intensive Treatment) and then were tracked for 5 years. Specifically, the investigators wanted to know how the program would affect long-term weight loss and renal function in patients with diabetes.

To find out, they recruited 104 patients with diabetes, 86.6% of whom had type 2 diabetes; the remainder had type 1 diabetes. The patients had an average age of 53.8 years and had a median duration of diabetes of 10.7 years. After 1 year, patients were stratified into 2 groups: those who had maintained at least 7% weight loss (Group A; 49.1%) and those who had not (Group B; 50.9%).

At baseline, the 2 groups had similar scores in terms of serum creatinine, eGFR, blood urea nitrogen (BUN), and albumin/creatinine ratio, or cardiovascular risk factors. The only area where a significant difference existed at baseline was triglyceride levels, which was significantly lower in Group B than Group A (117.9 mg/dL vs. 149.3 mg/dL, P = .04).

The patients in both groups lost an average of 8.8 kg at 1 year, and after 5 years, the average weight loss was 6.2 kg. The 5-year weight-loss broke down to an average of 8.3 kg in group A and 4.2 kg in group B.

Both groups saw improvements in SBP, but only group B’s improvement reached statistical significance (from 128.6 mmHg to 121.4 mmHg, P< .05). Both groups saw decreases in serum creatinine (group A: from 0.92 mg/dL to 0.85 mg/dL, P< .01; group B: from 0.92 mg/dL to 0.84 mg/dL, P< .01). eGFR also increased in both groups (group A from 86.0 mL/min/1.73 m2 to 97.7 mL/min/1.73 m2, P< .001; group B from 84.3 mL/min/1.73 m2 to 97.2 mL/min/1.73 m2; P< .01). No changes were noted in albumin/creatinine ratio.

On the other hand, A1c decreased by 0.3% in group A (P< .001) but increased by 0.9% in group B (P< .001).

Corresponding author Osama Hamdy, MD, PhD, and colleagues said there are several possible reasons that renal function appeared to improve in these patients regardless of blood pressure or glycemic control improvement, such as a reduction in chronic inflammatory processes related to obesity and diabetes, or perhaps specific features of the Why WAIT program, a diet that includes low glycemic index carbohydrates, higher monounsaturated fat and fibers, and less sodium. However, the investigators said the current study was not designed to compare the Why WAIT program to other programs, and thus its particular benefits would need to be studied in a subsequent trial.

The authors noted some limitations, such as the lack of a control group and the fact that the study was conducted at a single tertiary care center. Still, the authors said the study gives an important window into the long-term effects of ILI, showing that some of its renal function benefits are durable for 5 years.

“This improvement is seen with weight change over time and is not related to weight maintenance or weight regain after the intensive weight loss period,” they concluded. "This improvement is also independent of the change in systolic blood pressure and glycemic control.”

The study, "The Effect of Intensive Lifestyle Intervention on Renal Function in Patients with Diabetes and Obesity in Real-World Practice: A 5-Years Longitudinal Study," was published online in Human Nutrition & Metabolism.