Patient Outcomes Affected by Cardiorespiratory Fitness, BMI
An exercise class at the Butler, PA, VAMC. New research suggested that exercise can help type 2 diabetes patients improve their fitness and avoid taking statins, which can increase their need for insulin. Photo from Butler, PA, VAMC
WASHINGTON, DC — In patients with Type 2 diabetes mellitus, cardiorespiratory fitness and body mass index (BMI) play a role in statin-related progression to insulin therapy, according to a recent study.
The study, published in the journal Mayo Clinic Proceedings, evaluated the association between statin therapy, cardiorespiratory fitness, BMI and progression to insulin therapy in type 2 diabetes mellitus. Researchers for the study were affiliated with the Washington, DC, VAMC.1
The American Diabetes Association recommends statin therapy for all patients with Type 2 diabetes mellitus for the primary prevention of cardiovascular disease. Statin therapy for dyslipidemia, the imbalance of lipids such as high-density lipoprotein (HDL), low-density lipoprotein (LDL) or triglycerides in the blood, has been found to “significantly reduce all-cause and cardiovascular disease mortality of individuals with established coronary heart disease,” the study reported.
In spite of these positive outcomes, concerns related to statins have emerged, and “increased risk for developing Type 2 diabetes mellitus, insulin resistance and higher hemoglobin A1c and fasting glucose levels have been reported in patients treated with statins,” the study added, although some argue that the benefits of statin treatment outweigh the risks.
To better understand the effects of statin therapy, this study explored the link between statin therapy and the progression to insulin therapy.
Participants in the study were patients with Type 2 diabetes mellitus who were not treated with insulin, had no evidence of uncontrolled cardiovascular disease and who completed an exercise treadmill test between Oct. 1, 1999, and Sept. 3, 2020. Of these patients, 158,578 were treated with statins, and 28,774 didn’t receive statin treatment. The researchers established five age-specific cardiorespiratory fitness categories based on peak metabolic equivalents of tasks achieved during the exercise treadmill test, the study reported.
The study found that, in patients with Type 2 diabetes mellitus, “the statin-related progression to insulin therapy was associated with relatively low cardiorespiratory fitness and high BMI levels. The progression rate was lessened by increased cardiorespiratory fitness regardless of BMI,” according to the study.
The study recommends that “clinicians should foster regular exercise for patients with Type 2 diabetes mellitus to enhance cardiorespiratory fitness and to lessen the rate of progression to insulin therapy.”
“Clinicians should consider the cardiorespiratory fitness status of the patient at least as much as they consider body mass index (BMI),” Peter Kokkinos, PhD., a physiologist and health research scientist at the DC VAMC told U.S. Medicine. “Please note that the rate of progression to insulin increases progressively as BMI increases for those treated and not treated with statins. However, this increase is substantially higher in those treated with statins within each BMI category.”
The study’s results are significant because “each patient has the capacity to control the progression of diabetes by engaging in daily exercise,” Kokkinos wrote in an email.
“The bottom line is [that] the adverse effects of fatness are modulated by fitness,” Kokkinos said. “Our findings support that it is better to be fat, but fit, than skinny and unfit. However, the combination of fitness and normal body weight is more effective in lowering the progression of diabetes (progression to insulin) than either approach alone. The good news is that you can achieve both by engaging in adequate levels of physical activity. Exercise helps control body weight and lowers the progression rate to insulin (one stone, two birds).”
During a follow-up period of nine years, the study found that “51,182 patients progressed to insulin therapy with an average annual incidence rate of 28.4 events/1,000 person-years. The adjusted progression rate was 27% higher in statin-treated patients, related directly to BMI and inversely related to cardiorespiratory fitness.”
“A progressively higher rate was noted in statin-treated vs. non-statin-treated patients within all BMI categories, ranging from 23% for normal weight to 90% for those with BMI of 35 kg/m2 and higher,” the authors wrote. The study noted the statin-cardiorespiratory fitness interaction revealed a 43% higher rate in the least-fit, statin-treated patients and a progressive decline with increased cardiorespiratory fitness to 30% lower risk in highly fit statin-treated patients.
Health Benefits
For healthcare professionals caring for patients with Type 2 diabetes mellitus, Kokkinos noted the “health benefits of statin therapy outweigh the risk of increasing the rate of progression to insulin.” As a result, the American Diabetes Association guidelines recommend statin therapy for all patients with Type 2 diabetes mellitus for primary prevention of cardiovascular disease, he explained.
“The risk associated with statins can be diminished and even abolished by simply engaging in an exercise program of moderate intensity (brisk walk) 30 to 40 minutes daily,” Kokkinos said. “This is likely to increase the fitness status of an individual by approximately 20% to 25% within six months. Over 37.0 million people in the U.S. have diabetes. The public health impact is substantial, if we get 25% of them to increase their fitness levels by 20%.”
For several decades, attention and resources were focused on controlling body weight, with limited success, Kokkinos added.
“Perhaps it is time for a paradigm change,” Kokkinos said. “Perhaps we should devote at least as much time and resources to increasing the physical activity levels of all people—and especially those with chronic disease such as diabetics. After all, the highest consumers of glucose are the muscles; and the more you use them, the greater the demand for glucose. Let them do what they are designed to do: work. By doing so, we are more likely to achieve and maintain normal body weight, lower blood sugar and perhaps lower the dose of diabetic medication.”
- Kokkinos P, Nylen E, Faselis C, Pittaras A, Samuel IBH, Lavie C, Doumas M, Heimall MS, Murphy R, Myers J. Progression to Insulin Therapy in Patients With Type 2 Diabetes According to Cardiorespiratory Fitness, Body Mass Index, and Statin Therapy. Mayo Clin Proc. 2023 Jun 29:S0025-6196(23)00201-X. doi: 10.1016/j.mayocp.2023.05.005. Epub ahead of print. PMID: 37389516.