Journals watch: Diagnostic imaging for back pain and blood testing for heart failure

Too busy to read all of the journals? Dr Bryan Palmer selects the latest papers of interest to GPs.

MRI may not improve diagnosis in older adults experiencing back pain (SPL)
MRI may not improve diagnosis in older adults experiencing back pain (SPL)

Diagnostic imaging for back pain

JAMA 2015; 313(11): 1143-53

In contrast to the recommendations for younger adults, many guidelines allow for older adults with back pain to undergo imaging without waiting four to six weeks.

The authors of this study from the US have questioned back pain as a red flag. They used a prospective cohort of 5,239 patients aged 65 years or older with a new primary care visit for back pain (2011-2013) without radiculopathy.

Having matched each patient with a control, they looked at back and leg pain disability scores at 12 months in those who had early imaging before six weeks and those who did not.

Among the 5,239 patients, 1,174 had early X-rays and 349 had early MRI/CT. At 12 months, neither group differed significantly from controls on the disability questionnaire.

The researchers concluded the value of early diagnostic imaging in older adults for back pain without radiculopathy is uncertain. We have to evaluate red flags in the context of the clinical presentation as a whole.

Blood testing for heart failure

BMJ 2015; 350: h910

Acute heart failure is the most common cause of hospital admission in the UK in people aged over 65 years, and mortality remains high.

It is not easy to diagnose - as the authors of this UK study suggest, we only get it right 40-50% of the time. But could the B-type natriuretic peptide (BNP) blood test, mainly used in the chronic setting, also be used in the acute setting?

A meta-analysis was carried out to determine the diagnostic accuracy of the BNP test. It was found that at the lower recommended thresholds of 100ng/L for BNP and 300ng/L for NT-proBNP, the peptides have sensitivities of 0.95 and 0.99, and negative predictive values of 0.94 and 0.98, respectively, for a diagnosis of acute heart failure.

Specificity is variable, so imaging is required to confirm a diagnosis of heart failure, but overall, the authors recommend this as a safe option to exclude acute heart failure.

Preventing cognitive decline

Lancet 2015

The Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) is a proof-of-concept RCT, in which the authors looked at a two-year multi-domain approach to prevent cognitive decline in at-risk elderly people. Using a dementia risk assessment tool, the authors enrolled 1,260 individuals aged 60-77 years.

The intervention group received intensive diet and exercise, cognitive training and vascular risk monitoring, while the control group received general health advice. The primary outcome was change in cognition.

After two years, the intervention group had 25% higher scores on the neuropsychological test battery, which measures mental function, than those in the control group.

The study will follow participants for at least seven years to see whether the reduced cognitive decline results in reduced diagnoses of dementia.

Vitamin D and cardiovascular risk

J Clin Endocrinol Metab 2015: jc20144551

In Australia, it seems we have been so good at 'slip, slop, slap' sun protection that most of us are now vitamin D deficient. GPs have been recommending supplementation, but can too much be harmful?

This study from Denmark looked at the possible association between 25-hydroxyvitamin D levels and the risk of cardiovascular disease mortality.

The researchers used data from a single laboratory centre in Copenhagen, and from a sample of 247,574 subjects, analysed levels of vitamin D and mortality rate over a seven-year period after taking the initial blood sample. During that time, 16,645 patients died.

The study confirmed a correlation between mortality rates and low levels of vitamin D (<50nmol/L), but also that increased mortality was noted for those patients with levels >100nmol/L.

But before we all rush off to see the phlebotomist, they also pointed out that association is not causation and an RCT might be needed.

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

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

  • Research a list of red flags in acute back pain for presentation and discussion at a clinical meeting. Produce a checklist for practice clinicians.
  • Invite a cardiologist to discuss the presentation and management of acute heart failure.
  • Audit the last blood level of vitamin D for patients prescribed supplements and aim to maintain at 50-100nmol/L.

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

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