The Lancet has published the results of a meta-analysis that aimed to assess the benefits and risks of aspirin therapy in the primary prevention of vascular events. This study has been reported in the general media (BBC) and builds on previous analyses.
The analysis was conducted by the Antithrombotic Trialists' Collaboration and included data from six trials with 95,000 participants. Aspirin therapy produced a 12% relative risk reduction (absolute risk of 0·51% with aspirin versus 0·57% control per year) in serious vascular events mainly driven by reductions in non-fatal heart attacks. Aspirin treatment also increased major gastrointestinal and extra-cranial bleeds (0·10% versus 0·07% per year). These figures equate to a number needed to treat (NNT) of 1,667 for one year to prevent a serious vascular event compared to a number needed to harm (NNH) of 3,334 for major gastrointestinal and extra-cranial bleeds in the same time period.
The authors conclude that in primary prevention "aspirin is of uncertain net value as the reduction in occlusive events needs to be weighed against any increase in major bleeds". They also note that further research is under way.
Action: Clinicians should ensure that other modifiable risk factors (lifestyle, smoking, blood pressure, blood lipids) for cardiovascular events are managed appropriately in individuals who are identified as being at higher risk. Recommendation of aspirin therapy requires a careful consideration of the potential risks and benefits.
The National Institute of Health and Clinical Excellence has published new guidance for the month of May.
There are three clinical guidelines that may impact on primary care covering coeliac disease, low back pain and type 2 diabetes (update).
The coeliac disease guideline (QRG) covers the recognition and assessment of coeliac disease and the care of children and adults who are undergoing the diagnostic process for coeliac disease.
The low back pain guideline (QRG) specifically addresses the care and treatment that people who have persistent non-specific low back pain.
The type 2 diabetes guideline (QRG) provides an update to previous guidelines by clarifying the place in therapy for gliptins (sitagliptin and vildagliptin), glitazones (pioglitazone and rosiglitazone) and exenatide. These treatments are recommended in cases where there is intolerance to established agents (metformin or sulphonylureas) or in combination with the established agents when initiation of insulin is unacceptable for employment, social or other reasons.
Action: Clinicians who see and treat any of the above conditions will find these guidelines useful and informative.
The National Prescribing Centre has published MeReC Extra 39 (PDF) which covers the results of the DART-AD study and the update to the schizophrenia guidelines from the National Institute for Health and Clinical Excellence (NICE).
This MeReC discusses the DART-AD study which found that patients with Alzheimer’s disease who continued on treatment with antipsychotic medication with the aim of controlling behavioural or psychiatric problems had a higher risk of death than those who were switched to placebo.
DART-AD was a 12 month study in 165 patients with Alzheimer’s disease. 77% of those patients who received placebo were still alive at the end of the study compared to 70% of those who received active treatment with an antipsychotic.
The NPC recommend that clinicians implement NICE recommendations (QRG) that antipsychotic drugs are only used in cases of severe distress or where there is a immediate risk of harm to the patient or others.
This MeReC also discusses the recently updated NICE guidance for schizophrenia (QRG). Previously the guidance recommended using second generation (atypical) antipsychotics but recent reviews have indicated that treatment choice should be based on individual needs as opposed to the potential for side effects.
Action: Clinicians who see patients with Alzheimer’s disease or schizophrenia will find this information useful and informative.
The Lancet has published the results of a meta-analysis that aimed to whether intensive control of glucose reduces macrovascular events and all-cause mortality in individuals with type 2 diabetes.
The study selected five trials including data on 33,040 participants. Data were collected on non-fatal myocardial infarction, coronary heart disease (including fatal and non-fatal myocardial infarction), stroke and all-cause mortality. Average HbA1c was 0.9% lower in the intensive treatment group compared to the standard treatment group.
The analysis found statistically significant relative risk reductions in non-fatal myocardial infarction and coronary heart disease of 17% and 15% respectively. There was no difference in the rates of stroke or all-cause mortality.
The authors note several limitations of their analysis including differences in the study populations, insufficient data to allow subgroup analysis and the application of certain mathematical assumptions. It is also notable that four of the five studies reviewed were open label or unblinded.
The authors conclude that, "intensive compared with standard glycaemic control significantly reduces coronary events without an increased risk of death". It is also noted that stronger evidence for all-cause mortality reduction exists for lipid-lowering treatment and blood pressure reduction making these interventions crucially important.
Action: This analysis provides some reassurance that glucose control reduces some cardiovascular outcomes however blood pressure and lipid management remain the priority.
Diabetes, Obesity and Metabolism has published the results of a long term study comparing vildagliptin to glimepiride.
The study recruited 2,789 patients who were inadequately controlled on metformin monotherapy. Participants were then randomised to vildagliptin 50mg twice daily or glimepiride titrated up to 6mg daily. These results are a prespecified interim analysis after 52 weeks to ensure that vildagliptin is non-inferior to glimepiride.
Baseline HbA1c was 7.3% in both groups. This fell by 0.44% in the vildagliptin arm and 0.53% in the glimepiride arm. The difference was not significant and therefore non-inferiority was proven.
Other notable differences reported include a lower incidence of hypoglycaemia in the patients receiving vildagliptin and beneficial effects on body weight. Patients treated with vildagliptin lost approximated 0.23kg compared to a weight gain of 1.56kg in the glimepiride cohort. Additionally, no major differences were noted in haematological or biochemical parameters. This provides some reassurance with respect to the liver enzyme elevations that delayed the drugs launch however patients with clinically significant liver disease or abnormal liver enzyme results at screening were excluded from this study.
Action: These results start to build an evidence base for vildagliptin. Clinicians should await the NICE guidance on newer agents for type 2 diabetes due later this month before changing practice.