Journals Watch - Colon cancer, diabetes and PID

Missed this week's journals? Dr Jonathan Holliday brings you up to date with the latest research.

Cancer of the caecum: patients over 50 have a higher chance of colon cancer than those under 50
Cancer of the caecum: patients over 50 have a higher chance of colon cancer than those under 50

Identifying colorectal cancer in general practice BMJ 2010; 340: c1269
This is a systematic review and meta-analysis of 47 diagnostic studies involving adults presenting with non-acute lower abdominal symptoms.

Researchers found that those over 50 had a 10 per cent chance of colon cancer compared with a 2 per cent chance in those under 50. Family history has a high specificity but low sensitivity as only a small percentage of cases have a family history.

Weight loss has some diagnostic value but it tends to be a feature of later disease. Rectal bleeding and blood mixed with stool carry a higher risk.

When it comes to identifying signs in primary care, of the 53 patients identified by GPs as having a rectal mass only 12 (23 per cent) were found to have colorectal cancer. This number increased to 13 (46 per cent) of the 28 identified in the clinic.

One blood test that stands out is faecal occult blood (FOB) sampling, particularly if the immunochemical test is used.

Chlamydia testing and pelvic disease BMJ 2010; 340: c1642
The aim of this trial was to see if identifying and treating women with chlamydial infection would reduce the incidence of pelvic inflammatory disease (PID) in the following 12 months. This RCT tested 2,529 sexually active female students aged 16 to 27 years.

Participants were randomly allocated into immediate testing and treatment for chlamydial infection or storage and testing after one year. The prevalence of chlamydia was the same in the two groups (5.4 and 5.9 per cent respectively).

Ninety-four per cent of women were followed up after 12 months. The incidence of PID was 1.3 per cent in the screened and treated group and 1.9 per cent in controls.

Of the control group, 9.5 per cent of those who tested positive at baseline developed PID, compared with 1.6 per cent of the screened women (relative risk 0.17) but most episodes of PID (79 per cent) occurred in women who tested negative for chlamydia at baseline.

So while there may be some evidence that screening and treating is beneficial, it would seem that effectiveness of chlamydia testing to prevent PID over 12 months may have been overestimated.

Screening for type-2 diabetes Lancet 2010; doi: 10.1016/SO140-6736(09) 62162-0
Using a mathematical model, researchers tried to assess the cost-effectiveness of sequential screening strategies to detect new cases of type-2 diabetes.

Person-specific data was used to create a simulated population of 325,000 people aged over 30 years without diabetes. Different ages of initiation of screening and different frequencies of screening were compared.

Compared with no screening, all simulated screening strategies reduced the incidence of MI and diabetes-related microvascular complications (between three and nine events prevented per 1,000 screened) and all increased the number of quality of life years (QALYs).

Most strategies also reduced the number of simulated deaths but there was little or no effect on the incidence of stroke.

The study was American so it is difficult to know how the cost figures would translate to the UK but they varied between $10,000 per QALY for screening every six months starting at age 30, to $15,000 per QALY for screening started at 45 and repeated annually.

The authors' suggestion was to start screening between 30 and 45 years and repeat every three to five years.

More evidence for the benefits of light-to-moderate drinking Am J Cardiol 2010; 55: 1328-35
Alcohol consumption has consistently been associated in epidemiological studies with lower risk of cardiovascular disease, in part attributed to an increase in HDL levels. This study, using data for 245,207 adults participating in the US national health interview survey, aimed to clarify some of the issues.

During a follow-up period of almost two million person-years there were 10,670 cardiovascular deaths. Light and moderate drinkers (up to 14 drinks per week for men and up to seven drinks for women) suffered fewer CHD and stroke deaths.

However, in heavy drinkers, whom they define as consuming more than 14 drinks per week, stroke mortality increases (relative risk of 1.25).

The authors suggest that this association is because hypertension and AF are risk factors for ischaemic stroke.

CHD and stroke risk in patients with psoriasis Am J Med 2010; 123: 350-7
Data was pooled from patients with moderate to severe psoriasis who were enrolled in two drug treatment trials (CHAMPION and REVEAL).

Risk of CHD and stroke were estimated using the Framingham risk score and a stroke risk function based on the Framingham heart study cohorts.

A total of 1,591 patients with moderate to severe psoriasis were identified. These patients had similar 10-year risk for CHD and stroke and compared with the general population, the 10-year risk of patients with psoriasis was 28 per cent greater for CHD and almost 12 per cent greater for stroke.

Adolescents' perceptions of cigarette brands J Adolesc Health 2010; 46: 385-92
This interesting study from Australia looked at the persuasive powers of cigarette packaging and the effect of plain packaging on perceptions of smoking among adolescents.

The study also aimed to identify the effectiveness of pictorial health warnings on cigarette packets. When brand elements such as colour, fonts and imagery were removed, adolescents thought the packs were less appealing, rated attributes of a typical smoker less positively and had more negative expectations of cigarette taste.

Pack appeal was further reduced when the pictorial health warning was increased in size from 30 to 80 per cent. These effects were most apparent among susceptible non-smokers, experimenters and established smokers.

Dr Holliday is a GP in Berkshire and a member of our team who regularly review the journals

THE QUICK STUDY

Colon cancer diagnostic signs vary in sensitivity and specificity.

Chlamydia testing may not reduce incidence of PID within the following 12 months.

Type-2 diabetes screening should start between 30 and 45 years.

Light to moderate drinkers were found to have fewer CHD and stroke deaths.

Psoriasis is associated with an increased 10-year risk for CHD and stroke.

Cigarette packets that are plainer and have larger pictorial health warnings resulted in more negative beliefs about cigarettes among adolescents.

 

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