Lifestyle intervention program may decrease cardiovascular risk in obese adults with diabetes

Obese adults with diabetes who adhered to an intense lifestyle intervention had reduced risks of cardiovascular disease for several months, although the benefits decreased over time, according to a five-year follow-up of the program.

Participants maintained a mean 6.4 percent weight loss five years after the initial 12-week program. At 12 weeks, participants’ cardiovascular risk factors significantly improved from baseline. During the first 18 months of follow-up, participants who sustained their weight loss had a significantly lower blood pressure, although their blood pressure eventually returned to baseline even if they sustained their weight loss.

Lead researcher Osama Hamdy, MD, PhD, of the Joslin Diabetes Center and Harvard Medical School in Boston, and colleagues published their results online in BMJ Open Diabetes Research and Care on Jan. 4.

“This weight loss was very impressive, since we know from previous research that if this population can maintain a 7 percent weight loss, they show a marked improvement in insulin sensitivity and many other cardiovascular risk factors,” Hamdy said in a news release. “To the best of our knowledge, this is the longest follow-up in the real world of clinical practice to show encouraging results that weight loss can be achieved and maintained.”

The researchers evaluated 129 adults who enrolled in Why WAIT (Weight Achievement and Intensive Treatment), a 12-week multidisciplinary program for weight reduction and intensive diabetes management that the Joslin Diabetes Center launched in 2005.

During the 12 weeks, participants met once weekly for two hours. The program consisted of medication adjustments, dietary intervention, exercise intervention, cognitive-behavioral intervention and group education related to weight management and/or diabetes. After the 12 weeks, participants were encouraged to attended monthly support sessions to help them maintain their weight loss.

Participants in the Why WAIT program had type 1 or type 2 diabetes and a body mass index (BMI) between 30 and 45 kg/m². They enrolled in the program from September 2005 to September 2008. Each group had 10 to 15 participants.

The mean age was 53.7 years old, the mean BMI was 38.3 kg/m² and the mean duration of diabetes was 9.6 years. Twelve patients had type 1 diabetes, while 117 had type 2 diabetes.

The researchers measured metabolic parameters at baseline, after 12 weeks of the intervention and every three to six months during participants’ regular visits for a five-year period. The measurements included hemoglobin A1c, lipid profile, low-density lipoprotein (LDL) cholesterol and blood pressure. They also recorded the participants’ body weigh weekly during the first 12 weeks and then during their regular appointments. In addition, they measured the waist and hip circumference and body composition at the start of the program and after 12 weeks.

After one year, the researchers split the participants into two groups based on whether they maintained a 7 percent or greater weight loss. Of the participants, 47.3 percent failed to maintain a 7 percent weight loss (group A), while 52.7 percent maintained at least a 7 percent weight loss (group B).

At baseline, the groups had similar cardiovascular risk factors, which included hemoglobin A1c, blood pressure and lipid profile. Participants in group B had a significantly higher BMI, waist circumference, fat mass and fat free mass at baseline.

After 12 weeks, participants in group B lost a mean of 29.3 pounds, while participants in group A lost a mean of 17.7 pounds. At one year, the mean weight loss was 33.4 pounds and 5.4 pounds, respectively. Participants in group B continued to have a significantly higher mean weight loss during five years of follow-up. At five years, participants in group B lost a mean of 23.1 pounds, while participants in group A lost a mean of 8.4 pounds.

For participants in group A, their mean hemoglobin A1c level decreased from 7.5 percent to 6.7 percent after 12 weeks, but it increased to 7.7 percent at one year and 8.0 percent at five years. For participants in group B, their mean hemoglobin A1c level decreased from 7.4 percent to 6.4 percent after 12 weeks, but it increased to 6.8 percent at one year and 7.3 percent at five years.

Participants in group B maintained their improvement in lipid profile for five years. They also had a significantly lower blood pressure for 18 months.

Although participants who regained weight had an association with deterioration of hemoglobin A1c and serum trigylcerides, they continued to have improvements in LDL cholesterol and high-density lipoprotein (HDL) cholesterol despite regaining their weight.

The researchers mentioned a few limitations of the study, including that they did not have a comparative control group. They also noted that many of the parameters they measured were surrogate markers of cardiovascular risk and might not reflect improvements in cardiovascular outcomes. In addition, the study was only conducted at one tertiary care center, so the results might not be generalizable to other patient groups. Further, they could not control for medication changes and could not determine if the groups were treated differently after the initial 12 weeks.

“Although most of the initially observed benefits gradually disappear over time, their disappearance occurs slower in those who sustain weight loss,” the researchers wrote. “[Hemoglobin] A1C and triglycerides are the first parameters to rapidly deteriorate with weight regain while the improvement in LDL-cholesterol and HDL-cholesterol continues for long duration even with weight regain. [Blood pressure] rebounds slowly over the first 18 months of follow-up. The rate of its rebound is significantly slower in those who sustain weight loss.”