Up to half of patients with diabetes develop neuropathy. A review of six studies by Brian Callaghan, M.D., found that aggressive management of blood glucose can prevent this complication. Current clinical trials led by Rodica Pop-Busui, M.D., Ph.D., are examining other ways to prevent and treat diabetic neuropathy.
3 Papers, 1 Disease
U-M diabetes studies examine blood pressure, neuropathy and mortality
issue 17 | fall/winter 2012
The management of patients with diabetes has evolved greatly in recent years, with a greater emphasis on tight glucose control and closer attention to risk factors such as hypertension and neuropathy.
U-M researchers who study patterns of diabetes care and patient outcomes have recently published intriguing papers that physicians may want to consider as they manage diabetic patients.
All the researchers are members of the U-M Institute for Healthcare Policy and Innovation, which brings together more than 400 health services researchers from across U-M and partner organizations.
STUDY 1: BLOOD PRESSURE
Aggressive efforts to lower blood pressure in people with diabetes are paying off – perhaps too well, according to U-M Health System and VA Ann Arbor Healthcare System researchers.
In Archives of Internal Medicine, the team reported that there have been dramatic improvements in blood pressure control among VA patients with diabetes, with as many as 82 percent of patients having blood pressure controlled and 94 percent getting appropriate treatment.
But the team also found that over 8 percent of the 977,000 VA patients nationwide with diabetes are possibly being over-treated. Meanwhile, 6 percent were not being treated as aggressively as they could be.
That suggests it might be time to reconsider the current one-size-fits-all approach to blood pressure control, and turn to a new model that adjusts the blood pressure goal according to the individual. Modern electronic health record systems should help make this possible.
"Appropriately treating blood pressure in people with diabetes is extremely important, and good blood pressure control should still be the goal to reduce risk of heart attack, stroke and other conditions," says first author Eve Kerr, M.D., director of the Center for Clinical Management Research at the VAAAHS and professor of internal medicine at the U-M Medical School.
The team looked back at electronic records from people with diabetes and high blood pressure who were treated at any of 879 VA hospitals and clinics in 2009 and 2010. Almost 714,000 of them were between the ages of 18 and 75.
Drawing on the expertise of dozens of VA clinical and measurement experts, they developed a "clinical action measure," or way of assessing the appropriateness of a patient's care by looking at treatment factors and contraindications, not just the target blood pressure.
Appropriate hypertension management was defined as a blood pressure either less than 140/90 or less than 150/65; or having appropriate management of elevated blood pressure (medication intensification or being on three or more hypertension medications). Potential overtreatment was defined as having blood pressure that was less than 130/65 while also receiving three or more hypertension medicines or having recent medication increases.
One-goal-for-all benchmarks were set years ago when blood pressure control for people with diabetes was poor across the board. But now, a more sophisticated approach is likely needed, Kerr notes.
As a first step, the VA system will adopt the blood pressure clinical action measure to motivate appropriate blood pressure management for patients based on their risks and treatment characteristics. The same could be done in non-VA settings, says Kerr.
STUDY 2: NEUROPATHY
Aggressive control of blood sugar levels in people with diabetes can help prevent neuropathy, according to a new systematic review in The Cochrane Library by a team led by a U-M neurologist. However, the review suggests that optimal target levels need to be established to prevent serious complications.
Up to half of patients with diabetes develop neuropathy in their feet and legs, and strict glucose control has been seen as a way to stave the condition off. But evidence for the effects of this approach has not been systematically reviewed until now.
Brian Callaghan, M.D., Eve Kerr, M.D., and Christine T. Cigolle, M.D., M.P.H., are among the U-M researchers focusing on diabetes and its complications.
The results analyzed in the review are drawn from six studies investigating the risk of neuropathy in people who received enhanced glucose control treatments including extra insulin injections, medication and diet changes.
The review looked at evidence in Type 1 and Type 2 diabetes separately. In two studies involving 1,228 people with Type 1 diabetes, significantly fewer people developed neuropathy each year with enhanced glucose control treatment compared with routine care. In four studies involving 6,669 people with Type 2 diabetes, the reduction in new cases of neuropathy was small and not statistically significant.
"Overall, this evidence suggests that a more aggressive approach to controlling sugar levels can be effective in delaying the onset of neuropathy in diabetes," said lead author Brian Callaghan, M.D., assistant professor in the Department of Neurology at the U-M Medical School. "The results also highlight the differences between Type 1 and Type 2 diabetes. The less dramatic effect of enhanced glucose control in Type 2 diabetes may indicate that other factors, besides high glucose levels, may be important in causing nerve damage in these patients."
However, the risk of adverse effects associated with the treatment, including hypoglycemia, was higher with enhanced glucose control. The researchers say further research is needed to optimize target levels for safe treatments that will both prevent neuropathy and minimize serious side effects.
"Although these results show clear benefits for preventing neuropathy in people with diabetes, they should be weighed against potential adverse effects," said Callaghan. "Future studies must establish target levels for glucose control that will balance benefits and side effects."
Study 3: Mortality
Middle-aged and older adults with diabetes – even those living in nursing homes or having multiple other health issues – may survive longer with careful management of their diabetes risk factors.
Those findings, published in the Journal of Gerontology, revealed that even older adults may benefit from interventions that can prevent or delay retinal, neuropathic, cardiovascular and renal complications of diabetes.
"We went into this thinking that people in the limited health group would have substantial mortality, but with the exception of patients over age 76 with the poorest health status, all showed strong survival rates," says lead study author Christine T. Cigolle, M.D., M.P.H., an assistant professor of Family Medicine and Internal Medicine at the U-M Medical School and research scientist at the VAAHS.
The study found that while adults in the older age groups were more likely to have difficulty managing the disease and to have poor health status, middle-aged adults constituted the largest number of diabetes patients to have self-management difficulties.
Blindness, cognitive impairment and having multiple diseases requiring multiple medications were among issues that complicated their ability to manage their diabetes. The finding that medically complex patients survive to five years also supports inclusion of older patients in clinical trials to determine whether their outcomes replicate those of younger, healthier diabetes patients.
The research was based on nationally representative data from the U-M Health and Retirement Study.