Drugs to reduce blood sugar levels can do more harm than good in elderly patients with type 2 diabetes, a study has reported
Researchers from University College London and the University of Michigan in the United States used data from the UK Prospective Diabetes Study, a 20 year study of type 2 diabetes treatments involving more than 5000 people in the United Kingdom. They modelled the net gains or losses to quality of life associated with treatments for lower blood sugar and calculated additional impacts on quality of life from published medical evidence on the burden, safety, and efficacy of different treatments.
Specifically, the researchers looked at the effectiveness of diabetes treatments in preventing associated diabetes complications such as kidney, eye, and heart disease, and they compared the reduced risk of such complications with the increased risk of side effects and the burden of taking pills or injections. They published their findings inJAMA Internal Medicine.1
The results showed that, for many people, the benefits of taking diabetes medications were so small that they were outweighed by the minor harms and risks associated with the treatment. The benefits of treatment declined with age, and by age 75 the harms of most treatments were likely to outweigh any potential benefits.
John S Yudkin, emeritus professor of medicine at University College London, emphasised that the aim of treatment was not to lower blood sugar for its own sake but to prevent debilitating or deadly complications. “If the risk of these complications is suitably low and the burden of treatment correspondingly high, treatment will do more harm than good. The balance between the two can never be defined by a simple figure like blood sugar level,” he said.
A diagnosis of diabetes usually requires an HbA1c above 6.5% (48 mmol/mol), although the patients at greatest risk of morbidity have an HbA1c above 8.5% (69 mmol/mol). Typically, glucose lowering therapies will reduce HbA1c by around 1%.
While someone with type 2 diabetes who begins treatment at age 45 and reduces their HbA1c by 1% may gain up to 10 months of healthy life, if their diagnosis comes at age 75 they may gain as little as three weeks of healthy life. Yudkin noted, “Whether this is worth 10-15 years of pills and injections with potential side effects is ultimately up to the patient.”
The impact of different treatments on quality of life depends not only on their particular side effect profiles but also on the perceptions of patients. In particular, patients will consider that insulin has a more detrimental effect on quality of life than oral therapies because of the need to inject daily and the propensity for weight gain.
“In many cases, insulin treatment may not do anything to add to the person’s quality life expectancy,” said Yudkin. “If people feel that insulin therapy reduces their quality of life by anything more than around 3-4%, this will outweigh any potential benefits gained by treatment in almost anyone with type 2 diabetes over around 50 years old.”
The researchers said that their findings applied to most type 2 diabetes patients with HbA1c levels below about 8.5% (69 mmol/mol) and that the benefits of treatment were likely to be greater for around a third of patients with very high blood sugar levels.
Source: www.bmj.com
