More BMI Recording Needed to Meet UK Health Targets

Liam Davenport

May 01, 2019

GLASGOW — The planning of services around weight management and type 2 diabetes prevention may be hindered by the poor recording of body mass index (BMI) in primary care, the results of a Scottish study suggests.

Kath Williamson, RGN, DN, Department of Human Nutrition, University of Glasgow, and colleagues examined data from 12 general practices in Scotland, covering more than 77,000 adults.

Presenting the results at the 26th European Conference on Obesity, she said that, while three quarters of adults had had their BMI recorded by their general practitioner (GP) at some point, less than a third had in the past 2 years.

Incomplete Data

While there was also wide variation in BMI recording between practices, rates increased substantially in the past 2 years.

Nevertheless, comparison with national health survey data showed that there were discrepancies in obesity rates, with GPs recording more cases of obesity grades I and II and severe obesity but fewer normal weight and overweight adults.

Kath Williamson said in a news conference that "we often hear about obesity in the news and think we have all the BMI data we require to plan effective management services.

"What this data shows us is that’s not the case. All of our datasets have weaknesses, and we need more complete, current, routine, BMI data."

She added: "There’s a big drive to use data from electronic health records in smart city innovation and data-driven innovation but we need to recognise the gaps that these datasets have, and the reasons for variation between national health survey prevalence rates and real life prevalence rates."

Kath Williamson told Medscape News UK that, to improve BMI recording, "we probably need to broaden it out a little.

"It shouldn’t just be GPs but other health professionals as well, and I think that we need to train people to raise the issue of weight.

"I think they are very nervous of doing that, as other people have referred to, and that’s not been tackled by the NHS."

Kath Williamson said: "It would be good to see some more training around that for people and make them comfortable to do it."

Results Could Be Worse

Dr Matthew Capehorn, clinical manager, Rotherham Institute for Obesity, and medical director, LighterLife, a weight loss company, was not involved in the study.

He told Medscape News UK that the study was "interesting" and, "as a GP, I am surprised that it’s not worse than this".

He pointed to limitations with the study, such as the relatively small number of practices and it being unclear whether the adults had attended their general practice, rather than simply being registered.

Nevertheless, Dr Capehorn said that "the principle that the authors apply is clinically relevant," adding: "We need-up-to-date BMI levels in order to advise patients correctly on their weight and associated health risks."

He pointed out that recording BMI "is only a part of the clinical jigsaw" however, as something needs to be done with the information, such as referring patients to weight management services, or screen for comorbidities.

Dr Williamson said that the planning of effective weight management services, which is important for achieving remission of type 2 diabetes, relies on accurate and up-to-date BMI data.

The 2017 Scottish Health Survey (SHeS) indicated that 29% of Scottish adults have a BMI of at least 30.

However, a review suggested that only between 28% and 37% of adults have had their BMI recorded in the past year, and only between 58% and 79% have ever had their BMI recorded.

Study Details

To examine rates of BMI documentation in Scottish primary care, the researchers conducted searches of the electronic records of adults aged ≥16 years at 12 broadly representative general practices.

This yielded a total of 77,591 adults.

The team found that 75% had ever had their BMI recorded, while 31% had had it done in the past 2 years.

There was wide variation between practices in terms of the proportion of adults whose BMI had been recorded in the last 2 years, ranging from 20% to 42%.

Interestingly, rates of BMI recording by GPs per month increased almost three-fold between April 2016 and March 2018.

Comparing the levels of obesity recorded by the GPs with the SHeS, the researchers found that GPs identified fewer people with a BMI of less than 18.5–24.9 kg/m2, at 27% versus 33%, and with a BMI of 25–29.9 kg/m2, at 33% versus 36%.

However, GPs found more individuals with a BMI of 30–39.9 kg/m2 than the SHeS, at 31% versus 26%, and with a BMI of over 40 kg/m2, at 7% versus 3%.

Discussing the findings, Kath Williamson said that GP recording of BMI may be affected by missing data, due to lack of attendance at the GP's, excess GP workload, and a low priority given to BMI recording.

The data may be skewed towards higher BMI categories due to people with excess weight being more likely to have their BMI recorded.

In contrast, overweight and obesity rates may be underestimated in national surveys due to missing data and declining response rates, as well as the surveys excluding institutions such as care homes.

Kath Williamson was supported by an NHS Research Career Researcher Fellowship, an NHS Lothian Research Futures Award and a Royal College of Nursing Foundation Professional Bursary.

 No conflicts of interest declared.

 26th European Conference on Obesity: Poster PO1.236. Presented 29th April.


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