Osteoarthritis, back pain and pregnancy

A review of this week's medical research. By GP Dr Simon Hunter

Knee OA pain: duloxetine produces significant improvement in reported pain and associated depression (Photograph: Simon Fraser, Royal Victoria Hospital/SPL)
Knee OA pain: duloxetine produces significant improvement in reported pain and associated depression (Photograph: Simon Fraser, Royal Victoria Hospital/SPL)

Duloxetine for management of pain in osteoarthritis

Age Ageing 2012; 41: 646-52

Although knee osteoarthritis (OA) pain is thought to be a peripherally mediated nociceptive pain, it has been shown that inflammatory mediators released from the damaged tissue can also affect central nociceptors. The continual pain associated with OA can also lead to central sensitisation lowering the pain threshold. Central sensitisation has been ascribed to an imbalance between serotonin and noradrenaline.

Duloxetine, the selective serotonin noradrenaline reuptake inhibitor antidepressant, is already known to be effective in diabetic neuropathic pain.

This study examined the effect of duloxetine on pain from OA knee.

Two hundred and eighty-eight patients were enrolled and randomised to duloxetine or placebo. Their average age was 68 years; 89% were using NSAIDs and 97% were using paracetamol at baseline.

At 16 weeks, there was a significant difference in pain (p<0.001) on the visual analogue scale, self-reported pain, function but not stiffness; 48% said they had had a response from duloxetine compared with 9% from placebo. Depression also improved. Perhaps in 20 years' time duloxetine will be the new amitriptyline?

Improving adherence to lipid-lowering medication

Am J Cardiol 2012; 110: 666-72

This Netherlands study compared the compliance of newly started statins for both primary and secondary prevention in two groups. The controls were given statins in the normal way and the intervention group had repeated contact with a nurse who went through their personal risks, modifiable and unmodifiable, with a graphic presentation and targets set.

In addition to compliance, lipid levels, smoking, weight, anxiety and carotid intima thickness were measured. They were seen at commencement then at three, nine and 18 months by the nurse.

Compliance and anxiety levels were better in the intervention group (p<0.001). Compliance was 90-95% in the control group, compared with 95-100% in the intervention group. There was no difference in the other parameters measured. Whether the intervention they used is achievable in the real world is debatable, but more intensive counselling on commencing a statin would be a good idea.

Low-level drinking in early to mid-pregnancy

BJOG 2012; 119: 1180-90

This Danish study looked at lower levels of drinking in early to mid-pregnancy and its effect on the infant at the age of five years. The researchers assessed intelligence, attention and 'executive function' (planning, error correction, dealing with novel situations).

In the mothers, they assessed weekly amount of alcohol drunk and any binges and their frequency. Of the 1,628 women in the study, 758 reported no alcohol, 675 had one to four drinks a week, 20 women had more than nine drinks a week and 1,133 said they had had at least one binge. One-third smoked.

They found no association with any low to moderate drinking or any binge drinking in early to mid-pregnancy with any neurodevelopment of the children at five years of age.

Androgen suppression in prostate cancer

N Engl J Med 2012; 367: 895-903

This study compared continual androgen deprivation therapy (from an LHRH agonist) in patients one year post-radiotherapy for localised prostate cancer, against intermittent treatment. Intermittent treatment meant an LHRH agonist for eight months then stopping if the PSA was below 4ng/ml and checking the PSA every two months and restarting if above 10ng/ml.

The researchers found patients with intermittent therapy had better quality of life scores, though not as good as they had expected. They mooted that this might have been due to the timing of the assessments.

The median survival was 8.8 years in the intermittent group as opposed to 9.1 in the continuous group. They concluded that the intermittent therapy was non-inferior to the continuous therapy and drug costs were a third (although monitoring was more expensive).

This study could point the way to a new treatment algorithm for prostate cancer.

Bad backs in children from carrying backpacks

Arch Dis Child 2012; 97: 730-2

Some studies have shown that children with bad backs are more likely to have back pain in adult life – a burden on the health economy. Children are also becoming more sedentary.

This Spanish study looked at the association of heavy school-book backpacks and back pain, using the expert opinion that backpacks should not weigh more than 10% of body weight.

Children taking part in the study were weighed with and without their backpacks and their parents filled in a questionnaire on lifestyle and back pain.

The mean age was 14 and 92% of them used a backpack with two straps. Mean bag weight was 7kg and 61% of children carried a backpack >10% of body weight. For 18% of children, the bag exceeded 15% of body weight. Children carrying a bag in the top quartile of weight had a 50% higher risk of back pain. This was higher in girls, especially older girls. There was no significant increase in structural back pathology associated with bag weight.

While there are clear methodological problems with this study, for example, the self reporting of back pain, there does seem to be a strong message about expecting children to carry heavy weights on their back every day.

  • Dr Hunter is a GP in Bishop's Waltham, Hampshire, and a member of our team who regularly review the journals
CPD IMPACT: EARN MORE CREDITS

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

  • Enquire about rucksack or school bag weight when assessing children with back pain, especially older girls.
  • Audit how many patients commenced on a statin are still taking it a year later.
  • Consider the patient's quality of life when prescribing. Is there any advice you can offer about side-effects?

Save this article and add notes with your free online CPD organiser  Take clinical tests and claim certificates for CPD at myCME.com


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