NASH AND NAFLD, WHAT PREVALENCE AND COMORBIDITIES (updated the 22 Aug 2017)




Numerous studies have been published on the prevalence of NASH and NAFLD, some of which are contradictory, or are based on particular populations, which distorts the results. What are the last data’s?

 

Zobair Younossi, Aaron B. Koenig, Dinan Abdelatif, Yousef Fazel, Linda Henry and Mark Wymer published in ‘Hepatology' an excellent meta-study, compiling more than 50 scientific publications, in February 2016:

"Global epidemiology of nonalcoholic fatty liver disease-Meta-analytic assessment of prevalence, incidence, and outcomes"

A second  recent study by Chris Estes, Homie Razavi PhD, Rohit Loomba MD, Zobair Younossi MD and Arun J. Sanyal MD, partly based on the previous study, attempts to project the progression dynamics of the disease over 15 years

« MODELING THE EPIDEMIC OF NONALCOHOLIC FATTY LIVER DISEASE DEMONSTRATES AN EXPONENTIAL INCREASE IN BURDEN OF DISEASE »

We will support our projections on those very complete publications !

 

 

THE PREVALENCE OF THE NAFLD, THE ANTI-CHAMBER OF NASH

 

According to the first study, the overall average prevalence of NAFLD in the adult population was 25.24%

The stratification by region was as follows:

 

Not often asserted, Asia and the Middle East have higher NAFLD prevalence rates than the US and Europe, .

In the second study, they estimate the NAFLD rate in the US in 2015 at 30% of the adult population (> 15 years) and 25.8% of the general US population ie 83 million people.

In 2030 they estimate that the NAFLD rate in the US will be 33.5% of the adult population (> 15 years) and 28.4% of the general US population ie 100 million people.

 

THE PREVALENCE OF NASH

According to this meta-study, the rate of NASH in NAFLD patients who underwent a biopsy was 59.1%.

This result is considered partially biased because the indication of biopsy in a patient with a NAFLD is also related to ancillary diagnoses that induce a sub-population probably more predisposed to have a NASH than the large mass of NAFLD patients.

so this rate was stratified by region for NAFLD patients with a biopsy indication:

  • Asia -> 63.45%.
  • Europe -> 69.25%
  • North America -> 60.64%


 And NAFLD patients without biopsy indication:

  • Asia -> 6.67%.
  • North America -> 29.85%
  • Europe ->? (We will take the US rate)

 

The study assesses a corrected overall NASH rate because, according to them, only between 7% and 30% of NAFLD patients in the world population had an indication of biopsy, the global prevalence of NASH is therefore re-evaluated by their calculations between 1.5% and 6.45%.

 

However, it can be seen that the prevalence of NASH is higher in the industrialized countries that are those taken into account by analysts to estimate the NASH market.

If the actual rate is considered to be between the two extremes: Patients without biopsy indication and patients with biopsy indication, a basic calculation gives a range of prevalence of NASH by region.

  

By fixing the rate of NAFLD patients with biopsy indication in North America and Europe to 20% as an average (the authors estimate was : 7% to 30% for the world population), we obtain an estimated prevalence of NASH for :

 

  • North America: 8.69% (between 7.2% and 14.63%)
  • Europe: 8.95% (between 7.08% and 16.42%)

 

In the second study they carefully assess the number of NASH patients in the US in 2015 to 16.5 million people, or 5% of the US general population. Note that the adult rate is higher.

In 2030 they estimate that the affected US population will be 27 million people or about 7.67% of the general population. A small calculation shows that their projection predicts a NASH prevalence of 9% of the adult population.

 

Bringing this back to the adult populations size:

The respective populations of the USA and Canada are 321 million and 36 million

The US adult population (> 17 years) accounts for about 78% of its total population of 250 million people and that of Canada at 81% of its total population of 29 million.

So the total adult population in North America is about 279 million!

An average NASH prevalence rate of 8.69%, as previously calculated, results in an affected population of 24 million.

For Europe we will only consider the 5 most important countries in population size (sorry for others).

  • Germany -> 81 million - adult rate 84.6% - number of adults 69 million
  • France -> 66 million - adult rate 78.56% - number of adults 52 million
  • The United Kingdom -> 65 million - adult rate 79.3% - number of adults 51 million
  • Italy -> 60 million - adult rate 83.94% - number of adults 51 million
  • Spain -> 46 million - adult rate 82.85% - number of adults 38 million

 

Total adult population of these 5 countries: about 262 Million

 An average NASH prevalence rate of 8.95%, as calculated previously, gives an affected population of 23.4 million

On the basis of these calculations, North America and the main part of Europe together, account for about 48 million people with differents stages of NASH.

It goes without saying that the whole of this population with NASH is bigger than the part of the population considered needing a treatment (ITT), but it's remains huge.

Based on the figures published in the second study by applying equivalent rates between the US and Europe, we obtain:

By 2015 the estimated number of NASH patients on the general population (North America and Europe previously calculated) would be from de 31 million

By 2030 the estimated number of NASH patients on the general population (North America and Europe previously calculated) would be 53 million.


 THE PREVALENCE OF THE ITT POPULATION

By 2015, the number of NASH patients considered to be treated in the current phase 3 studies, (approximately ½ F1 + F2 + F3 fibrosis stages), estimated on the general US population would be 8.5 million or about 2.7% The general population. By 2030 this number would rise to 15 million people, or 4.3% of the general population.

Extrapolating its rates to the general population North America and Europe previously calculated, we obtain in 2015 a population to treat of 17.2 million people and in 2030 of 30 million people.


THE PREVALENCE OF THE NASH CIRRHOTIC POPULATION

By 2015 the number of NASH patients with estimated F4 fibrosis stage (cirrhosis) in the US general population is estimated at 1.3 million, or about 0.4% of the general population. By 2030 this number would grow to 3.5 million people or 1% of the general US population

By extrapolating its rates to the previously calculated North America and Europe population, a NASH population with a cirrhosis of 2.6 million and a population of 7 million by 2030 is obtained by 2015.


COMORBIDITIES

It is also interesting to examine the comorbidity rates observed for patients with NASH

The aforementioned study specifies the following rates that are impressive!

 For patients with NASH:

 

  • Obesity -> 81.83%
  • Type 2 Diabetes (T2D) -> 43.63%
  • Hyperlipidemia / Dyslipidemia -> 72.13%
  • Hypertriglyceridemia -> 83.33%
  • Hypertension -> 67.97%
  • Metabolic Syndrome -> 70.65%

 

This should lead to think about the molecules best able to treat a majority of these comorbidities at the same time as NASH and especially not to aggravate them.   


 

 G.Divry



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