Journals Watch - Aspirin, cardiovascular disease and tinnitus

A review of this week's medical research. By GP Dr Bryan Palmer

Risk of haemorrhage with aspirin could outweigh its cardiac benefits (Photograph: SPL)
Risk of haemorrhage with aspirin could outweigh its cardiac benefits (Photograph: SPL)

Weighing up the risks and benefits of aspirin
JAMA 2012; 307(21): 2286-94

The benefit of aspirin for primary prevention of cardiovascular events is relatively small and could easily be offset by the risk of haemorrhage.

This study from Italy set out to determine the incidence of major GI and intracranial bleeding episodes in patients with and without diabetes taking aspirin. It involved 186,425 individuals being treated with low-dose aspirin and 186,425 matched controls.

During a median 5.7 years' follow-up, overall incidence of haemorrhagic events was 5.58 per 1,000 person-years for aspirin users and 3.6 per 1,000 person-years for those not taking aspirin. Those with diabetes were at higher risk of bleeding irrespective of aspirin use.

The increase in bleed risk was equal in magnitude to the number of major cardiovascular events avoided in the primary prevention setting for patients with a 10-year risk of 10-20%.

Try weighing that up with the known decreased risk of bowel cancer with aspirin and we see the complexity of primary care in a nutshell.

The cardiovascular benefits of eating dark chocolate
BMJ 2012; 344: e3657

Researchers from Monash University, Melbourne, Australia, have studied the possibility that chocolate might be good for you. They would have been aware of studies showing that dark chocolate has antihypertensive, anti-inflammatory, antithrombotic and metabolic effects.

Their best case scenario analysis, using a Markov model, involved 2,013 participants who had hypertension and metabolic syndrome but no history of cardiovascular disease, and were not taking antihypertensives.

They found that eating 100g of dark chocolate daily can reduce cardiovascular events by 85 per 10,000 of the population treated over 10 years, and that £25 per person per year could be cost-effectively spent on prevention strategies using dark chocolate, assuming 100% compliance.

Extending the use of thrombolysis in acute stroke
Lancet 2012; doi:10.1016/S0140-6736(12)60768-5

Thrombolysis for stroke is, relatively speaking, the new kid on the block. The third International Stroke Trial (IST-3) sought to determine whether a wider range of patients might benefit up to six hours from stroke onset.

A total of 3,035 patients were allocated to 0.9mg/kg IV recombinant tissue plasminogen activator (rt-PA) or control.

The primary analysis was of the proportion of patients alive and independent, as defined by an Oxford Handicap Score of 0-2 at six months.

Within seven days, more deaths occurred in the rt-PA group (11%) than in the control group (7%), but at six months, 37% of patients in the rt-PA group versus 35% in the control group were alive.

The authors note that survivors who received rt-PA had better functional outcomes despite the early hazards, and that benefit was not diminished in patients aged over 80 years.

Treatment of tinnitus with cognitive behavioural therapy
Lancet 2012; 379: 1951-9

Many conventional and alternative treatments have been tried for tinnitus, usually with limited success.

This study from the Netherlands aimed to assess the effectiveness of a stepped-care approach, based on CBT, compared with usual care in patients who had tinnitus of varying severity.

Patients were randomly assigned using a computer-generated allocation sequence, stratified by tinnitus severity and hearing ability. Patients and assessors were masked to treatment assignment.

Primary outcomes were health-related quality of life (assessed by the health utilities index score), tinnitus severity (tinnitus questionnaire score), and tinnitus impairment (tinnitus handicap inventory score).

Compared with 247 patients assigned to usual care, 245 patients assigned to specialised care improved in health-related quality of life over 12 months and had decreased tinnitus severity and impairment. The treatment seemed effective irrespective of initial severity.

The risks inherent in BP performance measures
Arch Intern Med 2012; doi: 10. 1001/archinternmed.2012.2253

Performance measures that reward achieving BP thresholds may contribute to overtreatment. Here, the authors conducted a retrospective cohort study in 879 US Department of Veterans Affairs medical centres and smaller community-based outpatient clinics, looking at overand undertreatment.

The clinical action measure (designed to encourage appropriate medical management) for hypertension was met if the patient had a passing index BP (<140/90mmHg) at the visit or had an appropriate action.

Although 94% of patients met this target and hence 6% were undertreated, there was potential overtreatment in 8%. Facilities with higher rates for meeting the current threshold (<140/90mmHg) had higher rates of potential overtreatment.

The researchers say rates of potential overtreatment are currently approaching the rate of undertreatment, and high rates of achieving current threshold measures are directly associated with overtreatment and potential harm.

Use of pioglitazone and risk of bladder cancer
BMJ 2012; 344: e3645

Thiazolidinediones have developed a bit of a reputation in the past few years and this UK study does not add good news.

An association between use of pioglitazone and bladder cancer has been suggested, but the few population-based studies on this have produced conflicting results.

This retrospective cohort study, involving almost 116,000 patients from more than 600 general practices, was designed to try to give a clearer picture.

The authors identified 470 new cases of bladder cancer during follow-up. Overall, ever use of pioglitazone was associated with an increased rate of bladder cancer (rate ratio 1.83).

The rate increased as a function of duration of use, with the highest rate observed in patients exposed for more than 24 months (1.99) and in those given a cumulative dose greater than 28,000mg (2.54).

  • Dr Palmer is a former Hampshire GP now working in Australia and a member of our team who regularly review the journals.

Reflect on this article and add notes to your CPD Organiser on MIMS Learning

CPD IMPACT: EARN MORE CREDITS

These further action points may allow you to earn more credits by increasing the time spent and the impact achieved.

  • Carry out an audit of patients taking aspirin for primary prevention. How high is their cerebrovascular stroke risk?
  • Review your practice triage policy for stroke patients - consider receptionists implementing FAST (www.strokefoundation.com.au/blog/?tag=fast)
  • Review your patients who are still taking glitazones. Do the benefits outweigh the risks?

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