Alarm Bell as Chinese With Diabetes 'Losing 9 Years of Life'

Liam Davenport

January 18, 2017

Adults in China who are diagnosed with diabetes face an average loss of 9 years of life compared with individuals without the disease, largely due to poor clinical management, reveals a large-scale, nationally representative survey.

The study of over half a million individuals across both rural and urban areas indicates that, although the prevalence of diabetes in China remains low, diabetes is associated with a doubling of the all-cause mortality risk.

Moreover, diabetes is linked to increased deaths from ischemic heart disease, stroke, chronic kidney disease, chronic liver disease, infection, a range of cancers, and acute complications of diabetes. The research was published in the January 17 issue of the Journal of the American Medical Association.

Lead author Zhengming Chen, MD, DPhil, University of Oxford, Nuffield Department of Population Health, Oxford, United Kingdom, told Medscape Medical News that "this is the first time that we've got really good evidence about the prevalence of diabetes in China."

He noted that, although the overall prevalence of diabetes in China is still relatively low, "the problem is actually that most patients are not very well managed," adding, "That's why we see a very substantial risk of death for a wide range of disease, including cardiovascular disease."

For Dr Chen, the two "striking" outcomes are the high mortality risk from chronic renal disease and acute diabetic crisis, particularly in rural areas: "This reflects largely the failure of….the delivery of healthcare for diabetes."

Stressing the fact that the urban–rural difference in mortality rates in China is much higher than that seen in European and other high-income countries, he added: "This is quite important evidence to highlight the gap that needs to be focused on in the future."

In an accompanying editorial, Margaret Chan, MD, World Health Organization, Geneva, Switzerland, says that the study has "several strengths," including the large sample size, robust design, and stringent quality control.

She continues: "In perhaps its most significant contribution, the study identified several distinct patterns of diabetes-associated mortality not usually observed in countries with adequate data."

Dr Chan says that "the most concerning finding was the high proportion of deaths attributed to diabetic ketoacidosis, or coma, and chronic kidney disease, mainly related to diabetes rather than other or unspecific kidney disease," both of which are "indicative of poor clinical management."

However, she points to what she describes as perhaps the "most extensive reform of a health system in modern times," when China, in 2009, announced the "ambitious goal of training 300,000 family physicians within 1 decade."

She adds: "Although the feasibility of this goal has been questioned, China has delivered some stunning public-health success stories in the past."

Dr Chen agrees that the 2009 announcement was a "very positive development," although he points out that the delivery of primary healthcare "is not going to be immediate" and the results "remain to be seen." However, he emphasized: "You don't need very sophisticated kinds of treatments. You just need to make sure all the effective treatments are given."

No Prior Reliable Estimates of Excess Mortality Associated With Diabetes

In their paper, Dr Chen and colleagues note that, despite an increase in the prevalence of diabetes in China, there were no reliable estimates of the excess mortality associated with the disease. They therefore conducted a survey of 512,869 adults from five urban and five rural localities taking part in the nationally representative Disease Surveillance Points (DSP) system.

The participants completed a baseline survey between 2004 and 2008 that collected information on sociodemographic factors, medical history, including previously diagnosed diabetes, medication use, anthropomorphic measures, lung function, blood pressure, and heart rate.

A nonfasting venous blood sample was collected and on-site random plasma glucose testing was performed. Individuals with a glucose level of 140 to 200 mg/dL were invited back the following day for a fasting plasma glucose test.

Cause-specific mortality was monitored through the DSP system and electronic health-insurance records, with annual confirmation of survival through residential and administrative records.

The participants had a mean age of 51.5 years (range, 30–79 years), and 59.0% were female. Overall, 5.9% had diabetes, with 3.1% previously diagnosed and 2.8% detected via screening.

Diabetes was diagnosed in 4.1% of individuals in rural areas and 8.1% of those in urban centers. The prevalence of the disease among women was 6.1%, while that among men was 5.8%.

The median age at diagnosis among those previously diagnosed with diabetes was 53 years, and the median disease duration was 6 years. The team therefore estimated that less than 1% of these cases were likely to have been type 1 diabetes, so the vast majority would be type 2 diabetes.

The use of antidiabetic medications was reported by 77% of individuals previously diagnosed with diabetes, with 65% taking oral medications, 15% taking insulin, and 4% taking both. The use of oral agents was higher in rural than urban areas, while the opposite was found for insulin.

Despite the use of antidiabetic medications, mean plasma glucose levels were elevated in previously diagnosed individuals. The prevalence of statin use was also very low among diabetic individuals, at 2.6% or less, while blood-pressure–lowering medications were used by less than 29% of participants with the condition.

10 Years of Life Lost to Diabetes in Rural Areas

During 3.64 million person-years of follow-up, there were 24,909 deaths, of which 3384 were among individuals with diabetes. It was estimated that 10% of the deaths among diabetic patients were due to definite or probable diabetic ketoacidosis or coma.

Those with diabetes had a significantly increased risk of all-cause mortality, at an adjusted rate ratio (RR) of 2.00, which was greater in rural than urban areas, at an RR of 2.17 vs 1.85.

Diabetes was also associated with an increased risk of death from ischemic heart disease (RR, 2.40), stroke (RR, 1.98), chronic liver disease (RR, 2.32), infections (RR, 2.29), and cancers of the liver (RR, 1.54), pancreas (RR, 1.84), female breast (RR, 1.84) and female reproductive system (RR, 1.81).

Diabetes was also linked to a greatly increased risk of death from chronic kidney disease, which was especially high in rural areas, at an RR of 18.69 vs 6.83 in urban centers.

Overall, the researchers estimate that the 25-year probability of death among individuals diagnosed with diabetes at 50 years of age would be 69%, compared with 38% among those who remained free of diabetes at 75 years of age, equating to a loss of 9 years of life, or 10 years in rural areas and 8 years in urban areas.

Citing the Chinese 2030 Sustainable Development Goal of reducing noncommunicable disease mortality by one-third, the researchers say: "In China, mortality rates for adults aged 69 years or younger are decreasing due to many dietary, social, occupational, and healthcare changes and declined by about 15% during 2000–2010."

However, they note: "This decreasing trend may be slowed or even halted by increasing tobacco-attributed mortality in men and the increasing prevalence of diabetes in both sexes."

Indeed, as previously reported by Medscape Medical News, almost one-quarter of all cancers in men can be attributed to smoking in China, a figure that is set to rise as approximately 75% of men in China are ever-regular smokers, compared with less than 0.04% of women.

The authors of the current paper also point out that the risk of death associated with diabetes rises with increasing disease duration, "so the lifetime hazards will be even greater for people who develop diabetes during early adult life than for those who do so after they reach the age of 50 years."

They conclude: "As the prevalence of diabetes in young adults increases and the adult population grows, the annual number of deaths related to diabetes is likely to continue to increase, unless there is substantial improvement in prevention and management."

Funding for the baseline survey was provided by the Kadoorie Charitable Foundation. Funding for the long-term continuation of the study was provided by grants from the UK Wellcome Trust, a grant from the Chinese Ministry of Science and Technology, and a grant from the Chinese National Natural Science Foundation. The British Heart Foundation, UK Medical Research Council, and Cancer Research UK provided core funding to the Oxford Clinical Trial Service Unit. Dr Chen reports no relevant financial relationships. Disclosures for the coauthors are listed in the paper. Dr Chan reports no relevant financial relationships.

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JAMA. 2017;317:280-289, 264-266. Article, Editorial


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