On 4th July, instead of celebrating American style, I celebrated dietitian style as I attended the BDA’s (British Dietetic Associations) PENG Update Nutritional Requirements study evening. As I’ve recently moved from London to Manchester this was my first meeting with the British Dietetic Association: North West England and North Wales Branch. Despite being difficult to get to without a car- I left at 3:30pm and didn’t arrive until 6:04pm!!! It was overall a successful meeting. There were quite a few dietitians there who’d I’d met from Salford, the Christie, and Stepping Hill Hospitals and the dinner was more than expected –lasagna, curry, jacket potato, sandwiches, and they catered to your dietary need whether it be vegan, gluten free etc. It turned out to be a late night as we were there doing the case studies until 9pm.
Getting to the point, the main updates revolved around energy and protein requirements and for extreme BMI’s.
For energy, the older 2011 guidelines were based on predictive equations , specifically the Henry equation, which was designed for healthy populations and then adjusted for illness (stress factor) and then adding the PAL (physical activity level). They noted that the majority of clinical studies used the Harris Benedict equation which was published in 1919. That’s a century ago! The patients we now see in hospital are much different than the ones they saw back then. In 1900, the top 3 causes of death were infectious diseases—pneumonia and flu, tuberculosis, and GI infections versus the chronic health conditions we see today. In fact the average life expectancy in the western countries looked to be around 55 years old versus 80 – 85 years old today. We are dealing with people 30 years older!
https://ourworldindata.org/life-expectancy
The updated guidelines for energy requirements were based on 5 systemic reviews (nearly 44,000 papers) which were weeded through to determine which met their criteria. Taking all this into consideration, the guidelines are now more specific, taking into account the medical condition, age, and BMI of the patient.
The main message of the evening was that there are flaws to all the predictive equations and thus, the guidelines are moving toward a quicker way of estimating requirements - using kcal/ kg for Resting Energy Expenditure (REE) then multiplying by a single combined factor for physical activity and DIT. I do think will make our jobs a lot quicker. The new PENG provides over 20 pages of tables that are broken down by age and medical condition and also cites the study to support the information as well as providing the grade of evidence (ie ABC).
For protein they did a systematic review of the published guidelines for protein- 16 of them. Most of the studies used urine urea nitrogen to assess for adequate intake. They stressed the importance of having adequate protein AND energy intake except for BMIs over 30 where they made reference to the Choban studies recommending high protein, hypocaloric feeding.
Read more here: https://www.abadiazumaque.com/docs/recursos/r6.pdf
Extreme BMI’s over 30kg, the 2011 PENG suggests using BMR, stating that some countries use an adjusted body weight (I was doing this in the USA) though it’s not validated. If the patient is not metabolically stressed, they recommend to calculate requirements as usual per the Henry and subtracting 400 – 1000 kcal for weight loss OR <14kcal/kg actual weight and with high protein 1.2gm/kg actual weight vs 2-2.5gm/kg IBW. There was some question over what ideal body weight to use. I always used the Hamwi method for determing IBW and didn’t realize that it was really a USA based method though it is based on pounds and inches so I probably should have guessed. In the UK, some dietitians have said they were using the low end 18.5kg/m2 for the underweights and upper end 24.9kg/m2 for obese individuals.
In short, the new guidelines recommend the following:
For Underweight <18.5kg/m2 – use 25 – 30kcal/kg
For Obese >30kg/m2 - use Mifflin
I’ve been trying the new guidelines against the previous recommendations and it’s been fun to compare and contrast. Many of the results are quite similar and I particularly like the specific recommendations for the femur fractures as I’ve been covering that ward lately!
Let me know in the comments what you think of the new guidelines.
The new PENG pocket guide is set to come out end of July and the lucky members of PENG for the 2017 - 2018 year will receive a free copy!
Happy Calculating,
Kelly
Update: I received my copy of the PENG (yay!) and as amazing as it is, it’s super heavy and has many pages to flip through that I decided to create a 4 page cheat sheet instead. Click below for your cheat sheet!
