Cushing’s patients regulate blood sugar better after surgery
Most patients with diabetes, IGR saw improvements after procedure
Abnormalities in regulating blood sugar are prevalent in people with Cushing’s disease, but can be improved for many with surgery, a study finds.
The data emphasize the importance of careful blood sugar monitoring before and after surgery, according to the study’s authors. The study, “The outcome of abnormal glucose metabolism and its clinical features in patients with Cushing’s disease after curative surgery,” was published in Diabetes Research and Clinical Practice.
In Cushing’s disease, excessive amounts of the hormone cortisol are produced due to a tumor on the pituitary gland. Removing it is the mainstay treatment.
Prolonged exposure to excess cortisol can cause a range of health problems, including metabolic abnormalities. People with Cushing’s often metabolize glucose abnormally, which means how sugar (glucose) in the blood is processed and used is impaired. This can give rise to diabetes, which is where blood sugar levels are too high because the body doesn’t produce enough of the hormone insulin that lowers glucose by helping the body use it to produce energy, and/or it doesn’t respond well enough to it, a process called insulin resistance.
Studies show metabolic abnormalities like diabetes tend to improve for Cushing’s patients whose cortisol normalizes after surgery, but these have been inconsistent.
Blood sugar changes after surgery
Here, the scientists evaluated changes in glucose metabolism among 151 adults with Cushing’s disease in China who achieved biochemical remission after surgery. Glucose metabolism was assessed via an oral glucose tolerance test, which measures blood sugar after fasting, and again after consuming a sugary drink.
Before surgery, 80 people (53%) had abnormal glucose metabolism — 56 with diabetes and 24 with impaired glucose regulation (IGR), meaning they showed signs of elevated blood sugar, but not to the degree of having diabetes. In the year after surgery, 57 of those people (71.2%) saw improved glucose metabolism.
Among the 56 who’d been diagnosed with diabetes, 36 saw an improvement, with 12 transitioning to IGR and 24 developing normal glucose tolerance. Of the 20 people who still had diabetes, blood glucose levels and body mass index (BMI) significantly decreased, as did the number of diabetes medications they needed.
Of the 24 people with IGR before surgery, 21 transitioned to normal glucose tolerance after surgery. One person who had normal glucose tolerance before surgery deteriorated to IGR afterward.
Overall, at a year, the proportion of people with impaired glucose metabolism significantly decreased from 53% to 23.8%, with analyses showing the gains mainly occurring three to six months after surgery.
Lab tests showed significant reductions in measures of insulin resistance after surgery, meaning the metabolic improvements were related to their response to insulin, not to improvements in insulin production.
Among those who’d exhibited abnormal glucose metabolism before surgery, those who saw gains were younger and had been living with Cushing’s for less time. Those with abnormal glucose metabolism after a year had significantly higher BMI and rates of several metabolic abnormalities than people with normal glucose metabolism.
“[Cushing’s disease] patients should undergo routine glucose tolerance screening before and after surgery to evaluate their glucose metabolism status,” wrote the researchers, who said people with diabetes should be reevaluated after surgery to see if their treatment regimen needs to be adjusted. They said a longer follow-up might be preferable for assessing long-term changes in glucose metabolism after surgery.
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