Why are diabetes-related complications on the rise?

Diabetes has grown to become one of the most important public health concerns of our time. A review by the Harvard T.H. Chan School of Public Health has shown that the number of affected people has quadrupled in the last three decades. Type 2 diabetes (T2D), a type of diabetes traditionally occurring in adults and associated with obesity and a sedentary lifestyle, is now the ninth leading cause of death worldwide. It therefore comes as no surprise that this rapidly emerging epidemic is giving rise to a profusion of diabetes-related complications.

What are the usual diabetes-related complications?

As diabetes is a systemic disease, its effects are felt in virtually all parts of the body. Most diabetes-related complications are related to problems in the blood vessels, usually involving changes in blood flow or in the ability of blood to clot.

These complications are generally classified into two broad categories: microvascular (involving small blood vessels) and macrovascular (involving large blood vessels). Microvascular damage is responsible for causing eye, kidney, and nerve complications, while macrovascular complications encompass stroke and heart disease and are currently the leading cause of diabetes-related death and disability. In some areas of the body, such as the lower extremities (legs and feet), as well as in wound healing, both small and large blood vessels may be involved.

What are the trends in diabetes-related complication rates?

A recent viewpoint article in JAMA tackled the changing trends in diabetes-related complication rates. During the early 1990s, patients with T2D had reductions in life expectancy of up to 10 years, coupled with substantial risks for diabetes-related complications. However, through better education and medical care, these risk differences were slashed by as much as 60% between 1990 and 2010. The reduced risks chiefly represented reductions in heart disease, thus improving the long-term outlook for adults with T2D.

Yet between 2010 and 2015 the tides turned again, with an uptick in diabetes-related lower extremity amputations and hospitalizations, and a plateauing of the previously-reported improvements in heart disease and kidney failure. What’s interesting is the fact that this phenomenon figured prominently in young adults (ages 18 to 44).

What may have led to the changing trends in diabetes-related complication rates?

Why, then, do we have this paradoxical rise in complication rates, despite having more cutting-edge diabetes drugs and devices in the market, and learning more than ever about how the disease works? The JAMA article suggested that explaining these trends is especially challenging because of the numerous factors, ranging from individual patient characteristics to institutional issues and governmental policies, that may play a role. The article authors propose several theories:

First is the gradually changing profile of people newly diagnosed with diabetes. These young adults possess high rates of obesity, smoking, and sedentary lifestyles, as well as high blood pressure and cholesterol (lipid) levels, all contributing to an earlier onset of complications. The demographic of T2D is also veering toward a nonwhite population, with Asia being the epicenter of its global rise. Hence, the increase in complication rates may have been due to changes in the types of people who are developing T2D.

Second, there may have been an inadvertent relaxation of blood sugar targets (HbA1C) in these young adults. Intensive blood sugar control can cause low blood sugar (hypoglycemia), which can be particularly dangerous for older adults. When clinical organizations shifted toward less stringent blood sugar management guidelines in the late 2000s, with an eye on preventing hypoglycemia in older patients, this may have had unintended consequences for blood sugar management in young adults.

Third, broader socioeconomic factors may have been at play. The article observed that the complication rate reversal transpired after the noteworthy economic recession of 2008–2009, and at a time when high-deductible health plans started to pose added financial barriers to preventive care. Variations in insurance coverage of healthcare services, plus the skyrocketing costs of insulin and newer medications, may have likewise contributed to the rising complication rates.

On the other hand, it is also entirely possible that things may have simply boiled down to the increasing prevalence of T2D, or to earlier and better detection strategies.

Whatever the case, the exact reasons may be difficult to truly ascertain using observational and epidemiological approaches, which cannot definitively establish cause and effect.

What can someone with diabetes do to lower their risk of complications?

There is no single overarching strategy to lower one’s risk for diabetes-related complications. Prevention of complications and delay of their progression is always a two-way street between physician and patient. It comprises a multifaceted approach of reasonably sufficient blood sugar control that balances the benefits of diabetes medications with the risks of overly aggressive blood sugar control; lifestyle modifications; and regular screenings for eye, kidney, nerve, and heart-related conditions.

Nevertheless, the unexpected reversal of improvements in complication rates is worrisome, given its predominance in the young population. We need more focused studies to determine whether these negative trends are also occurring in other countries and are affecting particular ethnic groups. In addition, we need to know whether present treatments are effective in this younger, ethnically diverse subset of people developing diabetes-related complications.

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