Dengue chart to help GPs spot severe cases

It lists critical symptoms to watch out for, helping doctors to decide whether to ward patients
Irene Tham Straits Times 12 Jun 11;

It will soon be much easier for general practitioners (GPs) to sort out high-risk from low-risk dengue cases, which means most patients need not be warded.

The game changer is a 'decision chart' developed by Tan Tock Seng Hospital (TTSH) which specifies all the critical symptoms of patients who are more likely to develop the high-risk dengue haemorrhagic fever (DHF), in which uncontrollable bleeding occurs, leading to higher risk of death.

It also means less severely ill patients can avoid unnecessary hospitalisation costs and more hospital beds can be freed up.

Resources can then be channelled to monitoring the severe cases.

Deciding whether to ward patients or treat cases as outpatients has so far been based on doctors' judgment, said Associate Professor Leo Yee Sin, clinical director of the Communicable Disease Centre at TTSH.

Based on an ongoing survey of GPs by the hospital, more than 85 per cent of the 300-plus respondents carry out a blood test to diagnose and monitor patients suspected of having dengue.

But this tests only for red and white blood cell count. 'The test has to be fine-tuned to include other indicators like gum or nose bleeds and blood protein and urea levels to accurately predict if a case is severe,' said Prof Leo.

For instance, if a patient with fever also has bleeding gums or nose, low blood protein and high urea content, he should be warded. Otherwise, outpatient treatment suffices.

Prof Leo believes the decision chart TTSH plans to circulate among GPs will 'augment' their current practice.

She spoke to the media yesterday before marking the inaugural Asean Dengue Day at the hospital to raise awareness about effectively tackling dengue.

The chart is derived from a sophisticated software, the DHF calculator, which the hospital has used since mid-2007.

The TTSH-developed calculator, based on historical data of the hospital's warded patients, accurately predicts severity based on four indicators: bleeding gums or noses, white blood cell count, blood protein level and urea level.

From drawing of a patient's blood to getting the laboratory test results into the software, a decision can be made within two hours on whether the patient needs to be warded.

Previously, TTSH warded 80 per cent of its dengue patients, which Prof Leo said 'is not sustainable' in an epidemic. Since it started using the calculator, admissions have fallen to 40 per cent.

'The calculator is designed to be sensitive so we don't miss out any individual whose condition may worsen. Even then, we still manage to cut our admission rate by half,' she said.

The last major dengue outbreak in Singapore was in 2005, when it hit 14,209 people and killed 25.

Last year, more than 5,300 cases were reported, while the first five months of this year saw 1,600 cases.

No vaccination against dengue fever is available, but one is expected in five years. Worldwide, the disease affects 55 per cent of the population, with 75 per cent of the cases in the Asia-Pacific.

Decision-making tool helps doctors detect dengue more accurately
Vimita Mohandas Channel NewsAsia 11 Jun 11;

SINGAPORE: A decision-making aid at Tan Tock Seng Hospital is helping doctors better treat dengue patients.

The tool works by correctly predicting how severe the illness is and whether the patient has to be warded. It was tried out on over 200 dengue research patients last year.

Previously, doctors rely on their best judgement.

With this tool, they look at four clinical parameters - signs of bleeding, proportion of white blood cells, total protein and urea levels. The information is fed into a system and in a few seconds, it is able to forecast the probable outcome.

Along with another predictive tool called "Decision Tree", which is a questionnaire that doctors ask their patient to fill in, they have helped patients save on hospitalisation costs.

Associate Professor Leo Yee Sin, Clinical Director of the Communicable Disease Centre at Tan Tock Seng Hospital, said: "We implemented the dengue calculator model and the Decision Tree model to guide the clinicians to identify patients likely to progress to severe disease.

"When we started using this model, we realised 50 per cent reduction in the requirement of hospitalisation, so that helps us a lot in terms of patient management."

-CNA/ac