Pharmacological and lifestyle interventions to prevent or delay type 2 diabetes in people with impaired glucose tolerance: systematic review and meta-analysis
In their systematic review of diabetes prevention studies the authors
have reported only data on diabetes risk. We have shown that this is
misleading and results in substantial overestimation of the clinical
relevance of the effects of interventions for diabetes prevention (1). The
authors should also report the data on the underlying changes of glucose
and HbA1c values.
Health professionals rate diabetes prevention studies as being important
much more frequently when results are shown as changes in diagnostic
categories rather than as changes in the continuously distributed measure
of glucose (1). In our survey of diabetologists and diabetes educators
effects were interpreted as important or very important by 92% (255 of 276
survey participants) when results were presented as proportions of
subjects with diabetes (14% intervention group, 29% control group), by 87%
(248/285) when communicated as a risk reduction of 57%, but by only 39%
(110/284) when the corresponding fasting plasma glucose values were
presented (mean difference 0.3 mmol/L), and by only 18% (52/283) when
glycosylated haemoglobin values were used (6.0% versus 6.1%). These
results show that health care professionals view the benefit of preventive
interventions substantially higher when changes in diabetes risk are
communicated rather than related glycaemic parameters. Transformation of
continuous metabolic data into diagnostic categories may interfere with
understanding of study effects. This aspect has also been addressed in a
recent editorial in Lancet (2).
1) Mühlhauser I, Kasper J, Meyer G, FEND. Understanding of diabetes
prevention studies: questionnaire survey of professionals in diabetes
care. Diabetologia 2006; 49:1742-1746
2)Tuomilehto J, Wareham N. Glucose lowering and diabetes prevention:
are they the same? The Lancet 2006;368:1218-1219.
Rapid Response:
Glucose values should be reported
In their systematic review of diabetes prevention studies the authors
have reported only data on diabetes risk. We have shown that this is
misleading and results in substantial overestimation of the clinical
relevance of the effects of interventions for diabetes prevention (1). The
authors should also report the data on the underlying changes of glucose
and HbA1c values.
Health professionals rate diabetes prevention studies as being important
much more frequently when results are shown as changes in diagnostic
categories rather than as changes in the continuously distributed measure
of glucose (1). In our survey of diabetologists and diabetes educators
effects were interpreted as important or very important by 92% (255 of 276
survey participants) when results were presented as proportions of
subjects with diabetes (14% intervention group, 29% control group), by 87%
(248/285) when communicated as a risk reduction of 57%, but by only 39%
(110/284) when the corresponding fasting plasma glucose values were
presented (mean difference 0.3 mmol/L), and by only 18% (52/283) when
glycosylated haemoglobin values were used (6.0% versus 6.1%). These
results show that health care professionals view the benefit of preventive
interventions substantially higher when changes in diabetes risk are
communicated rather than related glycaemic parameters. Transformation of
continuous metabolic data into diagnostic categories may interfere with
understanding of study effects. This aspect has also been addressed in a
recent editorial in Lancet (2).
1) Mühlhauser I, Kasper J, Meyer G, FEND. Understanding of diabetes
prevention studies: questionnaire survey of professionals in diabetes
care. Diabetologia 2006; 49:1742-1746
2)Tuomilehto J, Wareham N. Glucose lowering and diabetes prevention:
are they the same? The Lancet 2006;368:1218-1219.
Competing interests:
None declared
Competing interests: No competing interests