Posted on October 29, 2014
This time around we’re looking at progress in preventing childhood mortality and the managing of type 2 diabetes.
The first of these the papers addressed in this edition of Richard’s Reviews is concerned with assessing the evidence surrounding a certain kind of treatment for patients with diabetes. Diabetes is a growing problem, and the range of treatments is developing. Therefore a systematic review such as this is quite necessary. This is the title:
Does combining GLP-1 agonists and basal insulin improve diabetic control without causing additional hypoglycamic episodes and weight gain?
Type 2 diabetes is a progressive, chronic disorder affecting the secretion and action of insulin, leading to abnormal glucose metabolism. Long-term, diabetes can cause vascular complications leading to problems with the heart, central nervous system, peripheral arteries, eyes, kidneys and peripheral nerves.
To prevent these complications, pharmacological treatment of type 2 diabetes involves the sequential addition of different classes of drugs to control blood glucose levels. If these treatments fail to control blood glucose, insulin replacement therapy may be started.
In the UK, GLP-1 agonists are generally used as third line treatments in people with type 2 diabetes and a BMI of more than 35. GLP-1 promotes insulin secretion after eating, and GLP-1 agonists therefore mimic this effect. The current study is a systematic review of randomised clinical trials comparing the combination of GLP-1 agonists and basal insulin against other anti-diabetic treatment strategies in adults with type 2 diabetes. The authors identified 15 eligible studies including 4,348 participants. The efficacy of these treatment strategies was evaluated in the following terms: change in HbA1c (a blood test that assesses control of blood glucose over preceding 3 months) from baseline and end of intervention; proportion of participants achieving a HbA1c of less than 7%; number of participants reporting a hypoglycaemic episode; change in weight between baseline and end of intervention. Notably, these outcome measures are all surrogate short-term measures; the study did not compare the interventions in terms of preventing the long-term vascular complications which are the source of much morbidity and mortality for patients with type 2 diabetes.
The study showed that combination treatment with a GLP-1 agonist and basal insulin results in improved blood glucose control, a reduction in weight and no increase in episodes of hypoglycaemia, compared to other treatment strategies.
As the authors state, combining a GLP-1 agonist with basal insulin achieves an ideal triad of short-term outcomes in diabetes: effective blood glucose control without additional hypoglycaemic episodes or weight gain. However, as the studies included in the systematic review lasted only 12-36 weeks, it cannot tell us anything about the effect of this strategy on long-term prevention of diabetic complications, which is the outcome that matters most to patients.
What is the trend in global childhood mortality 1990-2013 and which factors potentially underlie this trend?
During the past few decades, there has been considerable focus on the reduction of global child mortality. The Millennium Development Goal 4 (MDG4) set the target of reducing child mortality (mortality before 5 years of age) by two thirds from 1990 to 2015.
The current study used data from the Global Burden of Diseases, Injuries and Risk Factors Study to evaluate trends of child mortality from 1970 and the possible factors underlying these trends. Global child mortality levels decreased, on average, by 2.6% per year from 1970 to 1985, before slowing down for a decade until 1997, began to accelerate, and since 2005, have fallen by an average of 3.6% per year. The global under 5 mortality rate has decreased from around 80 to 45 deaths per 1,000 live births. Increasing income per person and better maternal education were two of the most important factors underpinning these trends. Despite these successes, the study predicts that on the basis of rates of change from 1990 to 2013, just 27 of 138 developing countries are likely to achieve the MDG 4 target.
Although many countries seem set to miss the MDG 4 target, the study finds that the acceleration of decreases in child mortality is beyond that which would be expected on the basis of changes in income. They suggest that studies like this will better focus efforts on countries where progress has been disappointing and warn that failure to address these issues could result in an additional 3 million preventable child deaths in 2030.