Statistics on Obesity, Physical Activity and Diet, England 2021

This part focuses on hospital admissions (inpatient settings only) related to being obese. Data is taken from NHS Digital's Hospital Episode Statistics (HES) database which contains details of all admissions at NHS hospitals in England.

The association between obesity and increased risk of many serious diseases and mortality is well documented and has led to the National Institute for Health and Clinical Excellence (NICE) developing guidelines on identifying and treating obesity.

Four measures are presented for the number of obesity-related hospital admissions:

1. NHS hospital finished admission episodes (FAEs) with a primary diagnosis of obesity – referred to as admissions directly attributable to obesity. A large proportion of these admissions involve a bariatric surgery procedure (see measure 3).

2. NHS hospital finished admission episodes with a primary or secondary diagnosis of obesity - referred to as admissions where obesity was a factor. A secondary diagnosis of obesity does not necessarily indicate obesity as a contributing factor for the admission, but may instead indicate that obesity is a factor relevant to a patient’s episode of care.

3. NHS hospital finished consultant episodes (FCEs) with a primary diagnosis of obesity, and a primary or secondary procedure for bariatric surgery - referred to as obesity-related bariatric surgery. 

4. NHS hospital finished consultant episodes (FCEs) with a primary diagnosis of obesity, and a primary or secondary procedure for bariatric surgery, but excluding maintenance, revisional, and removal procedures - referred to as obesity-related primary bariatric surgery. In this measure most patients would only be counted once (for their initial procedure).  Though not commented on within the report, it is available in data table  4.1.

An FAE is the first period of inpatient care under one consultant within one provider.  An FCE is a continuous period of admitted patient care under one consultant within one healthcare provider. Please note that admissions do not represent the number of in-patients, as a person may have more than one admission within the year.

Bariatric surgery encompasses a group of procedures that can be performed to facilitate weight loss, although these procedures can also be performed for other conditions. It includes stomach stapling, gastric bypasses and sleeve gastrectomy. In general, such surgery is used in the treatment of obesity for people with a BMI above 40, or those with a BMI between 35 and 40 who have health problems such as type 2 diabetes or heart disease. 

Admissions directly attributable to obesity, by year and gender

Note that many of these admissions will be for bariatric surgery procedures, and changes over time may in part reflect changes in uptake of these procedures, and so are not necessarily prevalence driven.

In 2019/20 there were 10,780 hospital admissions with a primary diagnosis of obesity, a decrease of 3% on 2018/19 (11,117 admissions). 

3 in every 4 patients were female (75%) and this is similar over time.

Admissions where obesity was a factor, by year and gender

In 2019/20 there were just over 1 million (1,022 thousand) hospital admissions where obesity was recorded as the primary or a secondary diagnosis. This is an increase of 17% on 2018/19, when there were 876 thousand admissions. 

Some (though not all) of this increase may be due to hospitals being more likely to record obesity as a secondary diagnosis than they were previously. See the Data Quality Statement (coherence and comparability) for more information.

Around 2 in every 3 patients were female (64%) and this is similar over time.

Admissions by age group

For admissions directly attributable to obesity, the number increases to middle age, peaking at 45 to 54, before declining in older age groups.

69% of patients were aged between 35 and 64 and this is similar over time.

For admissions where obesity was a factor, the age distribution is more uniform.

Admissions where obesity was a factor by primary diagnosis (top ten diagnoses)

Of those admissions where obesity was a factor, but it was not the primary diagnosis (main reason for the admission), the most common diagnoses related to maternity issues and knee joint issues (arthrosis of the knee). Others in the top ten diagnosis types were the formation of gallstones (Cholelithiasis), heart disease and hip issues (arthrosis of the hip). 

Note that overall there were a large number of different primary diagnoses recorded for admissions where obesity was a factor, and collectively the top ten diagnosis types accounted for less than 20% of all these admissions (201 thousand of 1,022 thousand).

Admissions by deprivation level (rate per 100,000 population)

Admissions were mapped to Index of Multiple Deprivation deciles and rates age standardised using the European standard population.

Rates for both admissions directly attributable to obesity, and for admissions where obesity was a factor increase with the level of deprivation. 

Admissions directly attributable to obesity were over three times more likely in the most deprived areas (31 per 100,000 population), compared to the least deprived areas (9 per 100,000 population).

Admissions where obesity was a factor were over twice as likely in the most deprived areas (2,778 per 100,000 population), compared to the least deprived areas (1,139 per 100,000 population).

Admissions where obesity was a factor by Local Authority (rate per 100,000 population)

Admission rates have been age standardised and rounded to the nearest whole number.

Admission rates ranged from 626 to 4,081 per 100,000 population, with the highest admission rate over 6 times greater than the lowest rate. The national rate was 1,869 per 100,000 population.

Southwark, Wirral, Southampton, Lambeth, Newham all recorded admission rates of over 3,500 per 100,000 population.

West Berkshire, Wokingham and Redcar and Cleveland all recorded admission rates below 700 per 100,000 population.

Admissions rate per 100,000 population by Local Authority where obesity was a factor

Obesity-related bariatric surgery admissions, by year and gender

In 2019/20 there were 6,740 hospital admissions with a primary diagnosis of obesity and a main or secondary procedure of bariatric surgery. This is a decrease of 4% on 2018/19 (7,011). 

80% of admissions were for females and this is similar over time.

Obesity-related bariatric surgery admissions, by age group

A third of patients (33%) were aged between 45 and 54 and this is similar over time.

Obesity-related bariatric surgery admissions by deprivation level (rate per 100,000 population)

As with the other measures, obesity-related bariatric surgery admission rates increase with the level of deprivation. 

Admissions for obesity-related bariatric surgery were over 3 times more likely in the most deprived areas (19 per 100,000 population), compared to the least deprived areas (6 per 100,000 population).

Obesity-related bariatric surgery admissions, by Local Authority (rate per 100,000 population)

Admission rates have been age-standardised and rounded to the nearest whole number.

Admission rates ranged from 0 to 38 per 100,000 population. The national rate was 12 per 100,000 population.

South Tyneside (38 per 100,000 population), Sunderland (38 per 100,000 population) and Southwark (37 per 100,000 population) recorded the highest admission rates.

City of London and Isles of Scilly both recorded zero rates.

Note that variation in rates across Local Authorities may reflect differences in uptake of bariatric surgery procedures, and not necessarily differences in obesity prevalence.

Obesity-related bariatric surgery admissions rate per 100,000 population by Local Authority

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For more data relating to this section:

Data Tables: Statistics on Obesity, Physical Activity and Diet, England, 2021