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More studies with more patients are required to achieve a firm recommendation
on this matter.
9.3. Antiplatelett treatment
The decision to prescribe aspirin a in primary care of DM 2 patients must take into
consideration the benefits of the drug as it reduces the number of cardiovascular
events and the risk of adverse effects (mainly, digestive and haemorrhage).
The results of the RCT meta-analysis in primary care show that the benefit
of aspirin is closely related to baseline cardiovascular risk (178), thus the patients
with higher baselinel cardiovascular risk are those who benefit more from the
treatment. The meta-analysis includes five RCTs in primary care which also contain
a minority of diabetic patients (between 2% and 17%); the HOT (179) and
PPP (180) studies are the ones which include more diabetic patients (8% and 17%,
respectively, in contrast to the 2% of other studies. However, the meta-analysis
does not provide data on the effectiveness of aspirin in the diabetic patient’s subgroup.
The SIGN guide, based on the results of this study (178) and another metaanalysis
(181) has specified the cut-off of cardiovascular risk to be over 15% to
consider primary prevention with aspirin (182).
The only specific study on aspirin in DM is the ETDRS study (183) which
included 3,711 patients suffering from DM types 1 and 2 with retinopathy, half of
whom were under secondary prevention. The treatment with aspirin during seven
years did not reduce the incidence of AMI, strode or cardiovascular death in these
patients.
A meta-analysis on the effectiveness of aspirin in contrast to placebo in primary
prevention (184) included a total of nine RCTs which provided data on diabetic
patients. In this subgroup no statistically significant differences were found
in the incidence of severe vascular events (non-fatal AMI, non-fatal stroke or vascular
death), [RRR 7% (CI 95%: -1% to +15%)].
Two RCTs were later published in primary prevention that include diabetic
patients.
In the analysis of the PPP diabetic population subgroup (180) (1,031 diabetics
aged ³50 without prior cardiovascular disease), a slight and insignificant reduction
of severe vascular events was observed [RR 0.90 (CI 95%: 0.50-1.62%)],
far smaller than that observed in primary prevention of patients with other risk
factors, though where a significant reduction of the risk was observed (185). The
authors state that due to the limitations of the study (open and with a limited number
of patients, as it was interrupted prematurely), the results are not conclusive.
In another RCT carried out in primary prevention on women (186), which
included approximately a 10% of diabetic women, a reduction of cerebrovascular
disease was observed, though none related to AMI nor the main variable of cardiovascular
events.
SR of RCT
1+
CPG
4
RCT
1+
SR of RCT
1+
RCT
1+
78 CLINICAL PRACTICE GUIDELINES IN THE NHS