Guidelines often didn’t include recommendations on the frequency of testing, and where evidence was used, it did not address the fundamental question of whether the test in question was necessary or beneficial.

This lack of evidence for how often tests should be carried out means patients could be receiving tests unnecessarily. Over-testing can be a problem in healthcare, as it can lead to false positives, meaning further testing and stress for the patient, while wasting NHS staff time and resources. There is also a risk of false negatives, giving patients false reassurance. Finding the right balance is important, as not testing enough could delay diagnosis and treatment.

The researchers looked at the guidelines from the National Institute for Health and Care Excellence (NICE), the Scottish Intercollegiate Guidelines Network (SIGN), the Royal Colleges of Pathologists, Physicians and General Practitioners.

The team searched ClinicalTrials.gov, an international clinical trial registry, to see if there are any studies on this topic in the pipeline. Their search found no studies looking at the question of how often patients with these chronic conditions should be tested, or what an optimal testing regime would be.

Dr Martha Elwenspoek, Research Associate at the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care West (NIHR CLAHRC West) and lead author of the study, said: “Our review has revealed there’s a lot of uncertainty around this kind of testing in primary care. The lack of evidence to inform the guidelines isn’t that surprising, as it’s a difficult area to test with traditional study methods. It wouldn’t be ethical to only test one group of patients and not test another group with the same long-term condition, for example.

“Our review has shown a need to develop new, rigorous methods to enable evidence-based monitoring of chronic diseases in primary care.”

Dr Jessica Watson, a GP and NIHR Doctoral Senior Clinical Research Fellow at the University of Bristol's Centre for Academic Primary Care, and co-author of the study, said: “Interestingly, when we spoke to patients about this, there was a misconception that all test results are completely reliable and that more testing is generally a good thing. So it’s important for GPs, and the nurses and other practice staff who carry out these tests, to have an open discussion with the patient.

“Given this uncertainty around testing, health professionals should explain the drawbacks of testing as well as the benefits, so that the patient can make an informed decision. It’s also really important that GPs don’t over-use this kind of testing, doing tests ‘just in case’ or because they’ve already taken blood for something else. This may seem efficient but can have consequences for the patient that aren’t immediately clear.”

Paper:

Monitoring type 2 diabetes, chronic kidney disease and hypertension in primary care. Are the guidelines evidence based?
Martha Elwenspoek, Rita Patel, Jessica Watson, Penny Whiting. Published in The BMJ.