The prevalence of diabetes in China has quadrupled in recent decades with 100 million adults now affected. Because the increase in diabetes is recent, the full eventual effect on mortality is unknown.
A study published today in JAMA (the Journal of the American Medical Association) shows that, in China, people with diabetes diagnosed in middle age lose, on average, nine years of life, mainly due to inadequate treatment, particularly in rural areas.
Researchers from the MRC PHRU, University of Oxford and Peking University examined the association of diabetes with mortality in 500,000 adults aged 30 - 79 in the China Kadoorie Biobank (CKB), a large collaborative project initiated during early 2000s. Between 2004 and 2008 study participants were recruited in five rural and five urban areas of China and followed up for cause-specific mortality until 2014.
The study found that people with diabetes had twice the risk of dying during the follow-up period compared to other study participants. Diabetes was associated with increased mortality from a wide range of conditions, including heart disease, stroke, kidney disease, liver disease, infection, and cancers of the liver, pancreas and breast.
Professor Zhengming Chen, CKB Principal Investigator, programme leader and senior author of the report, said “In recent decades, Chinese adult mortality rates have been falling but this decrease will be slowed or even halted by diabetes, unless there is substantial improvement in treatment”.
Diabetes was more common in urban than rural areas of China (8% vs 4% respectively), but the associated health risks were higher in rural than in urban areas. The risk of dying from inadequately treated acute complications of diabetes (diabetic ketoacidosis or coma) was four times as great in rural as in urban areas, and even in urban areas it was much higher than in Western populations.
Although three-quarters of those known to have diabetes were being treated, their mean blood glucose levels remained much too high and few were being given cardiovascular-protective medication, such as statins and blood-pressure-lowering treatments.
Dr Fiona Bragg, first author of the report, said “Of the many people in China with diabetes, few are adequately managed. This is causing a lot of premature deaths, particularly in rural areas.”
Most previous studies have been in high-income countries where people with diabetes have reasonably good control of blood glucose and statins and blood-pressure-lowering drugs are widely used.
In 2009 China began an extensive reform of the health care system to address the severe shortage of family doctors and improve primary health care services. These reforms include the goal of training 300,000 family physicians within 1 decade.
Commenting on the paper in JAMA, the Director-General of the World Health Organization, Dr Margaret Chan said “In public health, what gets measured gets done. The quality of precise measurement reported by Bragg et al provides confidence that Chinese authorities will continue to move the country’s health reforms in the right direction, with results that also improve the prevention and control of diabetes”.