GPs can be confident in using their clinical judgement to exclude pneumonia, but about two out of three cases of pneumonia will be missed by relying on signs and history alone, a new study shows.
In the first large scale study to assess GPs’ ability to diagnose pneumonia in patients presenting with acute cough, European researchers found that a GP’s diagnosis was correct in 96% of cases where they had judged pneumonia to be absent based on history and a physical examination.
However, of the 140 patients in the study who were found to have pneumonia on chest radiograph, GPs only detected 29% of cases, often because the patient’s signs and symptoms were less severe.
The findings, published this week in the European Respiratory Journal, are based on a Europe-wide study of more than 2,800 primary care patients presenting with acute cough, including 453 assessed by GPs in England and Wales.
In the UK, GPs diagnosed pneumonia in 2% of patients, whereas pneumonia was diagnosed on chest radiograph in almost 7% of patients.
The patients whose pneumonia was only picked up on x-ray tended to have less severe symptoms such as fever, crackles and signs of systemic inflammatory response syndrome.
The Dutch study researchers say the high negative predictive value seen with a GPs’ diagnosis based on signs and history shows there is little justification for using broad spectrum antibiotics on the grounds of not wanting to miss a case of pneumonia.
They concluded: ‘This can support GPs to rely on their ability to exclude pneumonia and withhold antibiotic treatment in a large proportion of their patients.’
They added that it would be difficult to improve on the already high negative predictive rate for pneumonia, and thus there may be no value in using tests such as CRP to exclude the disease.
And while it might seem ‘worrisome’ that a large number of pneumonia cases detected on x-ray were not diagnosed on clinical grounds, the researchers say many of these patents had less severe disease that usually has a more benign course.
They concluded: ‘Moreover, we assume that the serious negative health effects of a “missed” pneumonia … can be limited by instructing patients to revisit if symptoms persist or worsen.’