- Seventeen million Americans have diabetes, and over 200,000 people die each year from related complications of their disease. (CDC 2002)
- Diabetes afflicts approximately 20 percent of all Americans age 65 and older, and about one quarter of African-Americans and Hispanics over age 65.
- Clinical trials have shown that intensive control of blood glucose, blood pressure, and lipids can dramatically reduce the risk of complications.
- New approaches to diabetes management are in development that potentially will reduce the morbidity and mortality from the disease.
Diabetes is a chronic disease of high blood glucose related to the impairment of blood glucose regulation. It can result from too little of the regulatory hormone, insulin, resistance to insulin, or both. Complications include heart disease, strokes, blindness, kidney failure, and peripheral vascular and nerve disease resulting in leg and foot amputations. Among U.S. adults, diagnosed diabetes increased 49 percent from 1990 to 2000. (CDC 2002) Diabetes disproportionately affects the elderly and certain ethnic and racial groups.
Percentage of Persons Age 65 & Over with Diabetes by Race/Ethnicity, 2000
Note: Respondents were asked if they had ever been told by a doctor or other health professional that they had diabetes. Persons who said they had borderline diabetes were considered “unknown.”
Source: National Health Interview Survey, 2000
Diabetes incurs a tremendous personal, social, and financial burden. Seniors with diabetes often experience a reduced quality of life. Moreover, diabetes is an expensive disease for older Americans. In 1997, for persons aged 65 and older, total direct medical expenditures attributable to diabetes in the U.S. exceeded $32 billion. (CDC 1999) The high price of diabetes includes frequent physician and emergency room visits and admissions to hospitals and nursing homes.
Optimal treatment of diabetes can improve the quality of life and reduce health care costs. A study published in JAMA in 1998 found that treating Type 2 diabetes with a medicine to improve blood glucose (glycemic) control improved the quality of life for patients and helped keep them out of the hospital and on the job. (Testa 1998) The study also showed that patients’ perceptions of their own physical and emotional health improved, while the number of bed days and hospital visits declined. Improved glycemic control can also significantly reduce the risk of developing microvascular complications (eye, kidney, and nerve disease). (CDC 2002)
Treatment and prevention for type 2 diabetes
Many patients initially control their diabetes with diet and exercise. Oral hypoglycemics are one popular form of drug treatment for type 2 diabetes. Oral hypoglycemic agents include sulfonylurea agents, metformin, and thiazolidinediones. Ultimately, most patients will require insulin. Improved formulations of insulin and methods of insulin delivery are currently in development.
Treatment with hypoglycemic agents may prevent individuals from developing diabetes. In the Diabetes Prevention Program, a clinical trial involving over 3,000 people at high risk for type 2 diabetes, diet and exercise that achieved a 5 to 7 percent weight loss reduced diabetes incidence by 58 percent in participants randomized to the study’s lifestyle intervention group. (Diabetes Prevention Program Research Group 2002) Treatment with metformin reduced the risk of developing diabetes in individuals at high risk for type 2 diabetes by 31 percent over 2.8 years. (Diabetes Prevention Program Research Group 2002) Starch blockers which delay the digestion and absorption of sugars from food, were also demonstrated to cut the odds that high-risk adults would develop diabetes by 25% over three years. (Chiasson 2002)
Rosiglitazone (Avandia®) is a newer oral hypoglycemic drug approved by the FDA in 2000. This drug is not covered in Ontario, Canada or New Zealand. (Ontario Ministry of Health and Long Term Care 2001; PHARMAC 2002)
In addition to glycemic control, blood pressure control and the use of angiotensin-converting enzyme (ACE) inhibitors in people with diabetes have been demonstrated to delay the progression of kidney disease. (Golan 1999; Parving 2001; Kshirsagar 2000) Kidney failure in diabetics reduces their quality of life and often shortens their life. Treatment of diabetics with relatively inexpensive ACE inhibitors improves their quality of life and results in dramatic cost savings. (Swislocki 2001; Golan 1999)
Drugs in the pipeline for type 2 diabetes
- New drugs to target the problem of insulin resistance, which is a factor in the pathophysiology of type 2 diabetes are being investigated. (NIH, NLM 2002)
- One compound, an enzyme involved in pathways contributing to small blood vessel damage, shows promise in treating diabetic peripheral neuropathy. (United Press International 2002)
- Drugs that regulate gene expression in fat and insulin responsive tissues are also being studied. (NIH 2002)
- A compound that stimulates insulin-producing cells in the pancreas is being studied. (NIH 2002)
Type 2 diabetes generally arises from a combination of insulin resistance and inadequate production of insulin in the beta cell of the pancreas; new therapies are targeted at both of these defects. Molecular mechanisms involved in glucose toxicity underlying the development of diabetes complications have also been elucidated, yielding new targets for therapy. Moreover, scientists anticipate additional new therapeutic targets will emerge from genetic studies underway to identify genes predisposing to type 2 diabetes and to diabetes complications. (NIH 2002)
In 2002, 23 drugs were in clinical trials for the treatment and prevention of diabetes. (PhRMA 2002) Some of the agents in development are aimed at optimizing glycemic control, reducing insulin resistance, reducing obesity, and preventing the complications of diabetes. (Olefsky 2001)
Multiple pharmaceutical companies are developing new insulin sensitizing drugs for treatment or prevention of type 2 diabetes. One class of drugs acts through a nuclear receptor to regulate gene expression in fat and other insulin responsive tissues. (NIH 2002) Agents in this class have been shown to improve glucose control in type 2 diabetes, and also to delay or prevent type 2 diabetes in high-risk women with a history of gestational diabetes. Since earlier drugs in this class had significant side effects, nearly all the major pharmaceutical companies are trying to develop improved drugs that are more potent and less toxic. Several companies are investigating other mechanisms to increase insulin sensitivity (i.e. decrease insulin resistance). (NIH 2002)
Preservation or enhancement of function of the insulin producing beta cells in the pancreas is an important target for therapeutic development for diabetes. Identification of the molecular events involved in beta cell growth and development and in glucose sensing and insulin secretion by this critical cell type has important implications for therapy. (NIH 2002) Several drugs are under development based on the activity of glucagon-like peptide-1 (GLP-1) which appears to enhance growth and function of insulin producing beta cells.
Understanding of molecular mechanisms involved in glucose toxicity and development of complications of diabetes is also yielding new therapeutic strategies. For example, NIH funded research identified a key signaling molecule involved in glucose toxicity. (NIH 2002) A phase II trial of an inhibitor of this protein for treatment of diabetic peripheral neuropathy has been recently completed. Phase III trials are planned or underway using this drug to treat neuropathy (nerve damage) and it will also be studied for retinopathy, the leading cause of blindness in American adults. (NIH 2002)