Rates. WAS: vs facebook... hmmm..

[Guest guest]

Pat wrote:

>

>

> How many people in the population actually have achalasia? How is that

> calculated?

>

> As I understand it the incidence is one per 100,000. But what does that

> mean?

>

There are two rates that are used, incidence, which as you correctly

said, is 1 new case per 100,000 people per year, and prevalence, which

is the number of people with it per 10,000 people and that is about 1

per 10,000 people. For children the incidence is something around 1 new

case per 1,000,000. So, in the US there is about 3000 new cases a year

and about 30,000 people with it. The numbers seem fairly consistent

around the world but there have been some variation between studies.

That is for primary achalasia. There are also secondary and pseudo

achalasia cases. In countries south of the US, Mexico through South

America there are many cases secondary to chagas disease. Cases such as

those do not count in the numbers for primary achalasia. Achalasia and

swallowing problems are more common among the older population.

There is an interesting thought experiment you can do regarding the

rates and age. If you imagine 100,000 babies born in the same year and

applied the 1/100,000 rate to them the number of achalasia patients

would go up by one each year. If you did that for a new group of babies

each year for 80 years, (to make things simple assume a life span of 80

years), because achalasia is for life, you would see the older groups

have steadily more members with achalasia. But that would give a

prevalence of 4 per 10,000 not 1 per 10,000. That tells us that the

incidence rate starts much lower than 1/100,000 and does not rise much

over many years of age. At some point in life the rate becomes higher

than 1/100,000 with age.

Achalasia in Iceland, 1952-2002: an epidemiologic study.

http://www.ncbi.nlm.nih.gov/pubmed/17420933

" The mean prevalence was 8.7 cases/100,000 and the overall incidence was

0.55 case/100,000/year. "

Achalasia: incidence, prevalence and survival. A population-based study.

University of Alberta, Edmonton, AB, Canada

http://www.ncbi.nlm.nih.gov/pubmed/20465592

" ... the incidence and prevalence of treated achalasia is 1.63/100,000

and 10.82/100,000, respectively. "

An epidemiological study of achalasia among the South Asian population

of Leicester, 1986-2005.

http://www.ncbi.nlm.nih.gov/pubmed/18027026

" The overall incidence in this study was 0.89 cases/10(5)/year. "

Esophageal achalasia in the Veneto region: epidemiology and treatment.

Epidemiology and treatment of achalasia.

Venice, Italy.

http://www.ncbi.nlm.nih.gov/pubmed/21116729

" The overall incidence of achalasia was 1.59 cases/100,000/year. "

UK incidence of achalasia: an 11-year national epidemiological study.

http://www.ncbi.nlm.nih.gov/pubmed/20515971

" The mean incidence of childhood achalasia in the UK from 1998 to 2008

is at least 0.18/10(5) children/year; this has risen over the last 11

years ... "

Here is one of the odd ones.

Achalasia in Zimbabwean blacks.

http://www.ncbi.nlm.nih.gov/pubmed/3983775

" The estimated incidence is 0,03/100 000 members of the population per

year, which is much less than the incidence in Europe and America. "

Here is a different rate. The hospitalization rate for the US.

Hospitalization for achalasia in the United States 1997-2006.

http://www.ncbi.nlm.nih.gov/pubmed/19517232

" The annual hospitalization rates of achalasia revealed a clear-cut

age-dependent rise between the youngest age group less than 18 years old

(0.25/100,000) and the oldest age group over 85 years old

(37.35/100,000). Between 1997 and 2007, the rates of hospitalization

remained largely unchanged for all age groups alike.

Epidemiology of hospitalization for achalasia in the United States.

http://www.ncbi.nlm.nih.gov/pubmed/8425436

" Achalasia discharge rates increased linearly from age 65 to 94 years. "

More interesting rates dealing with endoscopic treatment. (2011)

Epidemiology and practice patterns of achalasia in a large multi-centre

database.

http://www.ncbi.nlm.nih.gov/pubmed/21480936

" Among 521,497 upper endoscopies during the study period, we identified

896 patients with achalasia. ... Botox injection was most frequently

used as first choice of endoscopic therapy in 41%, followed by balloon

dilation in 21%, Savary dilation in 20%, Maloney dilation in 10%,

Rigiflex in 4% and other modalities in 4% of patients. "

(I think most people in this support group believe that Rigiflex

achalasia (30-40mm) dilator, or equivalent, should be the first

treatment in most cases. I think this reflect what many of us suspect,

that many GIs use whatever is on had during the first EGD and may not

even have an achalasia dilator.)

notan

[Guest guest]

Hi Notan --

That was an exceptionally informative explanation --

Very interesting.

Pat

On Mon, Jun 4, 2012 at 2:10 AM, notan ostrich <notan_ostrich@...> wrote:

> **

>

>

> Pat wrote:

> >

> >

> > How many people in the population actually have achalasia? How is that

> > calculated?

> >

> > As I understand it the incidence is one per 100,000. But what does that

> > mean?

> >

>

> There are two rates that are used, incidence, which as you correctly

> said, is 1 new case per 100,000 people per year, and prevalence, which

> is the number of people with it per 10,000 people and that is about 1

> per 10,000 people. For children the incidence is something around 1 new

> case per 1,000,000. So, in the US there is about 3000 new cases a year

> and about 30,000 people with it. The numbers seem fairly consistent

> around the world but there have been some variation between studies.

> That is for primary achalasia. There are also secondary and pseudo

> achalasia cases. In countries south of the US, Mexico through South

> America there are many cases secondary to chagas disease. Cases such as

> those do not count in the numbers for primary achalasia. Achalasia and

> swallowing problems are more common among the older population.

>

> There is an interesting thought experiment you can do regarding the

> rates and age. If you imagine 100,000 babies born in the same year and

> applied the 1/100,000 rate to them the number of achalasia patients

> would go up by one each year. If you did that for a new group of babies

> each year for 80 years, (to make things simple assume a life span of 80

> years), because achalasia is for life, you would see the older groups

> have steadily more members with achalasia. But that would give a

> prevalence of 4 per 10,000 not 1 per 10,000. That tells us that the

> incidence rate starts much lower than 1/100,000 and does not rise much

> over many years of age. At some point in life the rate becomes higher

> than 1/100,000 with age.

>

> Achalasia in Iceland, 1952-2002: an epidemiologic study.

> http://www.ncbi.nlm.nih.gov/pubmed/17420933

> " The mean prevalence was 8.7 cases/100,000 and the overall incidence was

> 0.55 case/100,000/year. "

>

> Achalasia: incidence, prevalence and survival. A population-based study.

> University of Alberta, Edmonton, AB, Canada

> http://www.ncbi.nlm.nih.gov/pubmed/20465592

> " ... the incidence and prevalence of treated achalasia is 1.63/100,000

> and 10.82/100,000, respectively. "

>

> An epidemiological study of achalasia among the South Asian population

> of Leicester, 1986-2005.

> http://www.ncbi.nlm.nih.gov/pubmed/18027026

> " The overall incidence in this study was 0.89 cases/10(5)/year. "

>

> Esophageal achalasia in the Veneto region: epidemiology and treatment.

> Epidemiology and treatment of achalasia.

> Venice, Italy.

> http://www.ncbi.nlm.nih.gov/pubmed/21116729

> " The overall incidence of achalasia was 1.59 cases/100,000/year. "

>

> UK incidence of achalasia: an 11-year national epidemiological study.

> http://www.ncbi.nlm.nih.gov/pubmed/20515971

> " The mean incidence of childhood achalasia in the UK from 1998 to 2008

> is at least 0.18/10(5) children/year; this has risen over the last 11

> years ... "

>

> Here is one of the odd ones.

> Achalasia in Zimbabwean blacks.

> http://www.ncbi.nlm.nih.gov/pubmed/3983775

> " The estimated incidence is 0,03/100 000 members of the population per

> year, which is much less than the incidence in Europe and America. "

>

> Here is a different rate. The hospitalization rate for the US.

> Hospitalization for achalasia in the United States 1997-2006.

> http://www.ncbi.nlm.nih.gov/pubmed/19517232

> " The annual hospitalization rates of achalasia revealed a clear-cut

> age-dependent rise between the youngest age group less than 18 years old

> (0.25/100,000) and the oldest age group over 85 years old

> (37.35/100,000). Between 1997 and 2007, the rates of hospitalization

> remained largely unchanged for all age groups alike.

>

> Epidemiology of hospitalization for achalasia in the United States.

> http://www.ncbi.nlm.nih.gov/pubmed/8425436

> " Achalasia discharge rates increased linearly from age 65 to 94 years. "

>

> More interesting rates dealing with endoscopic treatment. (2011)

> Epidemiology and practice patterns of achalasia in a large multi-centre

> database.

> http://www.ncbi.nlm.nih.gov/pubmed/21480936

> " Among 521,497 upper endoscopies during the study period, we identified

> 896 patients with achalasia. ... Botox injection was most frequently

> used as first choice of endoscopic therapy in 41%, followed by balloon

> dilation in 21%, Savary dilation in 20%, Maloney dilation in 10%,

> Rigiflex in 4% and other modalities in 4% of patients. "

> (I think most people in this support group believe that Rigiflex

> achalasia (30-40mm) dilator, or equivalent, should be the first

> treatment in most cases. I think this reflect what many of us suspect,

> that many GIs use whatever is on had during the first EGD and may not

> even have an achalasia dilator.)

>

> notan

>

>