Friday April 18 2008
Home testing is done using a blood sugar monitor
”Self-testing sugar levels could harm diabetics” is the headline in The Daily Telegraph today. Thousands of people with diabetes “could be doing themselves more harm than good by testing their own blood sugar levels”, as they are more likely to become anxious or depressed than those who do not, the newspaper says.
The media reports are based on a study which found that self-testing did not reduce the number of attacks of hypoglycaemia (when the blood sugar levels fall low enough to cause change in conscious level) but were linked to an increase in self-reported levels of depression. Another slant to the news story comes from a second economic study on home testing kits by a different research group, which suggests that they are costing the NHS an extra £90 per person per year, a total of £100million a year.
These reports will undoubtedly be of concern to the many people with diabetes who regularly monitor their blood sugar levels. However, it is important to note that this study investigated a particular group of people: patients newly diagnosed with type 2 diabetes only (commonly known as age-related diabetes and often associated with weight gain). The findings from the study do not apply to the thousands of people who have type 1 diabetes (which develops at a young age and is reliant on insulin injections in order to control blood sugar levels) or to people with type 2 diabetes who have had the condition for longer, who require insulin, or have other serious medical illness (as these people were excluded from the study).
Aside from the debate over home blood sugar testing for the newly diagnosed type 2 diabetic, it remains vital that diabetics maintain their blood sugar at as balanced a level as possible to avoid the many complications associated with diabetes. This should be monitored and carefully controlled in each individual patient in the best possible way
Where did the story come from?
Maurice J O’Kane and colleagues of Altnagelvin Hospital and University of Ulster, Northern Ireland carried out this research. The study was funded by Northern Ireland research and development office and was published in the (peer-reviewed) British Medical Journal.
The separate economic evaluation of another blood sugar monitoring trial was carried out by Judit Simon and colleagues of the University of Oxford, Johns Hopkins School of Medicine, USA and the University of Sydney. It was also published in the British Medical Journal.
What kind of scientific study was this?
This was a randomised controlled trial, known as the ESMON study, in which the researchers investigated the relationship between self-monitoring of blood sugar, actual blood sugar control and mental health.
The researchers randomised 184 people newly diagnosed with type 2 diabetes (aged less than 70 years; 60% male), excluding those who required insulin, had previous experience with blood sugar monitoring, other serious medical illness (including kidney or liver disease), or with diabetes as a result of other medical conditions. The participants were randomly allocated to either monitoring their blood sugar with a glucose monitor (testing four fasting and four post-meal blood sugar levels per week, with instructions on the actions to take in response to levels) or to no monitoring. Both groups of people received identical diabetes care and education from relevant health professionals over the period of one year.
At each three-monthly clinical visit, the participants had their HBA1C level measured (a reliable measure of blood sugar stability over time), and they completed a questionnaire of treatment satisfaction: the diabetes attitude scale. This included information about the impact on person’s life, implications of blood sugar control and the severity of the condition. They also completed a well-being questionnaire that included scores of depression, anxiety, energy levels and positive mental attitude. The study was designed to detect differences in HBA1C levels between the two groups and the participants received oral diabetes medications as appropriate to their blood sugar levels.
The economic evaluation of self-monitoring for diabetes was based on results of a separate trial, in which 453 people with type 2 diabetes had been randomised to no monitoring, self-monitoring or intensive self-monitoring with training in interpretation of results (the DiGEM trial). In this study, quality of life was assessed using the EuroQol EQ-5D questionnaire.
What were the results of the study?
In both groups, those self-monitoring and those not, HBA1C levels fell over the course of the 12 months (indicating improved blood sugar control) with no significant difference between the two, i.e. both as stable as each other. There was also no difference in the requirement for oral diabetic drugs, or in the number of episodes of hypoglycaemia (low blood sugar) reported. Those who were self-monitoring had significantly higher scores of depression at the end of the study (by 6%), but there was no difference in levels of anxiety, general well-being or energy.
In the economic evaluation, the other researchers found that the per-person costs over 12 months were £89 for standard care, £181 for self-monitoring and £173 for more intensive self-monitoring, with average increased costs of £92 for monitoring and £84 for intensive monitoring. They found that self-monitoring was also associated with significantly lower quality of life in both of the monitoring groups.
What interpretations did the researchers draw from these results?
The researchers conclude that at one year, in the group of newly diagnosed type 2 diabetics tested, they were unable to find any effect of self-monitoring upon blood sugar control measured by HBA1C, the number of episodes of hypoglycaemia or the use of oral diabetic drugs. However, monitoring was associated with a 6% higher score on the wellbeing depression subscale (with higher scores indicating greater depression). They say that the “possible negative effect of monitoring might be important and merits further investigation”.
What does the NHS Knowledge Service make of this study?
It is not surprising that patients with newly diagnosed type 2 diabetes found it had more of an impact on their lives and their mental comfort when they had to adapt to regular blood sugar testing compared with their counterparts who did not self-monitor and, to all intents and purposes, could continue life as they had previously. However, this does not mean that self-monitoring of blood sugar has no role in diabetes care. It remains vital that diabetics maintain their blood sugar at as balanced a level as possible in order to avoid the many complications associated with diabetes.
- Most importantly, this study was carried out in newly diagnosed type 2 diabetics only. They are a completely different population from the thousands of people with type 1 diabetes, who develop the condition at a young age and are reliant upon insulin injections to stabilise their blood sugar levels. They are also a different group from type 2 diabetics who have had the condition for longer, who have other serious medical illness or who have progressed to the stage where they require insulin injections. Findings from this study cannot be generalised to these groups.
- Although the study and the media reported that there was no difference in the number of self-reported episodes of hypoglycaemia, it is unclear from the study how this could have been measured. The self-monitoring group may have based this on their blood sugar level monitors to tell them that they were hypoglycaemic. However, the non-monitoring group may have had to base this on their body’s feelings of whether they were hypoglycaemic. If this were the case, there may have been times when they were not aware that they were hypoglycaemic despite having very low blood sugar. That is to say, the non-monitoring group may have underestimated the number of occasions on which they were hypoglycaemic compared with the monitored group.
- The researchers do not report whether depression scores at the beginning of the study were balanced between the groups. If they were not, any differences in the score at the end of the study may not be due to the intervention at all. Additionally, the significance of a “6% higher score on the wellbeing depression subscale” is unclear. This would not be the measure used to diagnose depression clinically. It should also be noted that there was no difference in levels of anxiety, general well-being or energy between the groups, which are also important measures of mental health.
The issue of self-monitoring of blood sugar being a “waste” or being a “harm” has been slightly over-emphasised by the news. All people with diabetes should continue to be monitored and carefully controlled in the best possible way, on an individual basis. This study will likely lead to further debate and research into the possible benefits and harms of home testing in diabetes.
Sir Muir Gray adds...
The most important variable for people with type 2 diabetes is their weight; they should focus on that and if they want to measure something else, they could measure how much they walk and try to walk an extra 3000 steps a day.