Alex Nowbar reviews the latest research from the top medical journals

Annals of Internal Medicine

Fat in Mexico
Gnatiuc et al prospectively measured the waist circumference, waist to hip ratio, and body mass index (BMI) of 150 000 residents of Mexico City and followed them for 14 years. These data confirm that each 5 units of BMI above 25 were associated with a 30% increase in mortality even after adjustment for confounders. A strong association with mortality was also shown for waist to hip ratio and waist circumference. The researchers excluded people who, at recruitment, had an HbA1c indicative of diabetes or a pre-existing chronic disease (including diabetes, renal disease, vascular disease, cancer, liver cirrhosis, and emphysema). They found that these conditions distort the association between obesity and mortality, because lower BMI could be protective for disease, but can also be a consequence of chronic disease. 

Cerebral palsy and mental health
Whitney et al compared adults with cerebral palsy to those without using a large nationwide claims database in the US. The prevalence of mental health disorders was much higher in those with cerebral palsy and even higher in those with cerebral palsy and neurodevelopmental disorders such as epilepsy or autism. The differences are dramatic, for example they found a schizophrenia prevalence of 2.8% in adults with cerebral palsy compared to 0.7% in those without cerebral palsy. This isn’t altogether unsurprising, but useful to know because it highlights the additional needs in this population. The authors suggest that screening for these conditions might help because mental health disorders could be treated and prevented. I’m not sure about that, particularly the prevention bit. I even think the higher prevalence of mental health disorders in those with cerebral palsy and neurodevelopmental disorders points towards underlying neurological factors that are unlikely to be modifiable with existing treatments. There are also likely to be social factors contributing to the higher prevalence and again, we don’t know how that can be modified. However, I do believe increased awareness of mental health disorders in people with cerebral palsy is likely to be a positive thing and this is an excellent study.

Lancet

Bowel preparation before colectomy
Does bowel preparation before colectomy reduce surgical site infections, including anastamotic leak? This Finnish trial randomised people to either mechanical and oral antibiotic bowel preparation or no bowel preparation. It found no difference in the rates of surgical site infections between groups. Rates of anastomotic leak and re-operation were very similar. This is research the way it should be. The surgeons had an inkling that mechanical and oral antibiotic bowel preparation might be beneficial based on observational data, but this could be confounded by comorbidities causing some patients to be less likely to receive bowel preparation and also more likely to get surgical complications. A randomised study was essential, and the trial was well-designed to answer the question, particularly by pushing for blinding of all staff as much as possible to avoid bias.

A nontrivial neurological entity
The NeuroVISION investigators conducted a prospective cohort study about covert stroke by performing brain MRI a few days after elective non-cardiac surgery. Have you heard of covert stroke? No? That’s probably because it doesn’t make much sense as a clinical entity. The main point of a stroke diagnosis is neurological deficit so by definition, if no neurological deficit is detected, it’s just an infarct. Or at least, that was the prevailing belief. 

Of the thousand participants in this multicentre study, 7% had a covert stroke. This was defined as an acute brain infarct detected on MRI with no clinical stroke symptoms. That seems like a lot for elective surgery but this was an above average risk population; the study only recruited people aged over 65 who were anticipated to be in hospital for at least two days. Those that had covert stroke were more likely to have cognitive decline at 1 year defined as a reduction in MOCA score of at least 2 points. So covert stroke may indeed be an important clinical entity requiring further study. 

At a quick glance, this study makes it seem like surgery is quite high risk for cognitive decline because over a quarter of people had cognitive decline at 1 year even though they hadn’t had covert stroke. However, the study isn’t actually assessing surgical risk at all as there was no non-surgical group. This study’s focus is that those who have perioperative covert stroke are at greater risk of cognitive decline.  

JAMA Internal Medicine

Diabetes care
Kazemian et al wanted to see what has happened to US diabetes care over time (2005 to 2016). They conclude that there wasn’t much improvement. They measured diabetes diagnosis, linkage to care, and achievement of individual and combined treatment targets. These measures are likely to link to morbidity and mortality so it is a shame that more is not being achieved. That women and nonwhite adults are less likely to reach diabetic control targets is worrying, but the solution is not obvious. Even in optimal circumstances, a patient can choose not to take advice because outside the clinic room the reality is too expensive or inconvenient or insignificant compared to that person’s other priorities. I wish we could measure how well our profession was doing at helping people achieve their personal health goals. In that realm, I like to think we are a lot better than we were in 2005.

Out of network billing
Brits, prepare to be shocked. Imagine you ended up going to a hospital outside of a pre-defined group of hospitals because of the timing or nature of your medical issue and that you got charged for this. (Of course in the US it’s an extra charge because you were going to get some charge anyway, but this would mostly be covered by the private insurance you had taken out.) That would be considered pretty outrageous. Well this is common in the US, and the proportion of emergency department visits and inpatient admissions generating “out-of-network” billing has risen to 42% in 2016. This places an additional financial burden on patients. This seems inherently unfair to patients, who may not have much choice as to where and when they become unwell.

Coaching for physicians
I met a life coach in the US once. What an American thing to do, I thought condescendingly. What I didn’t know was, I have luckily been receiving coaching of sorts from my mentors and colleagues over the years and it has been immensely helpful. I now realise that, of course, it makes sense that coaching can be concentrated into professionally delivered sessions. Dyrbye et al randomised physicians to six sessions of coaching or control. Those in the coaching group came out better in terms of burnout, emotional exhaustion and quality of life. Winner. I hope this type of intervention can be taken seriously and implemented widely.

JAMA

Hypertension patterns and dementia
Walker et al performed a prospective cohort study of people with blood pressure measurements in both midlife and late life and had 24 years of follow-up. Five hypertension patterns were defined, and rates of cognitive impairment and dementia were compared between groups. Midlife normotension with late life hypertension had a high risk of dementia. Midlife hypertension followed by late life hypertension had an even higher risk of dementia. And so did midlife normotension with late life hypotension compared with people who remained normotensive. This is very interesting. While hypotension could adversely affect the brain, there may be more at work here. For example, cognitive impairment may lead to low blood pressure due to changes in lifestyle resulting from the cognitive impairment.

NEJM

New injection for familial chylomicronemia syndrome
The main issue in familial chylomicronaemia is recurrent episodes of pancreatitis resulting from a deficiency of lipoprotein lipase. Currently this is treated by lowering plasma triglyceride levels, but this is often inadequate. Volanesorsen was tested in a double-blind, randomised controlled trial of 66 people in various countries. It successfully reduced triglyceride levels compared with placebo at 3 months. However, drug related adverse events were more common with some worrying thrombocytopenia, and the trial was too small to draw conclusions about whether the drug prevented acute pancreatitis.

Alex Nowbar is a clinical research fellow at Imperial College London.