NEWS - Channeling bias may explain Arava link to interstitial lung disease

May 31, 2006

Channeling Bias May Explain Leflunomide Link to Interstitial Lung Disease

NEW YORK (Reuters Health) May 30 - The risk of developing interstitial lung

disease (ILD) is increased among patients with rheumatoid arthritis (RA)

treated with leflunomide, according to findings published in the May issue

of Arthritis and Rheumatism. However, the association may be the result of

channeling of high-risk patients to leflunomide.

" Spontaneous reports of ILD in patients with RA treated with leflunomide, a

disease-modifying antirheumatic drug (DMARD), have been appearing recently, "

write Dr. Samy Suissa and colleagues from McGill University Health Center,

Montreal, Quebec, Canada.

To investigate, the researchers examined data on 62,734 RA patients who had

been treated with a DMARD. In a nested case-control design, each case of

serious ILD requiring hospitalization was matched to 100 controls to

estimate adjusted rate ratios (RRs) of serious ILD associated with DMARD

use.

Seventy-four patients were hospitalized because of serious ILD, which

corresponded to a rate of 8.1 per 10,000 patients per year. The use of

leflunomide was associated with an increased risk of ILD (adjusted RR 1.9).

The risk of ILD associated with leflunomide was not increased among patients

with no previous methotrexate use and no history of ILD (RR 1.2). The risk

was elevated among the remaining subjects (RR 2.6). Patients who had a

history of ILD were nearly twice as likely to have been prescribed

leflunomide as any other DMARD

" The increased risk of ILD in the patients treated with leflunomide appears

to be due to a channeling bias, where patients with a history of ILD may

have been preferentially prescribed leflunomide rather than methotrexate on

the assumption that, in contrast to methotrexate, no lung toxicity was

associated with leflunomide, " Dr. Suissa's team explains.

They conclude that for patients with no history of methotrexate use and no

existing ILD, leflunomide confers no excess risk of ILD.

Arthritis Rheum 2006;54:1435-1439.

http://www.medscape.com/viewarticle/533435

Not an MD

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org

May 31, 2006

, thank you for this article very informative. Question????? Does this

article infer that those of us who use MTX have a high risk for ILD? To me the

2nd to last paragraph indicates so...Please clarify if you can....Thanks for all

that you do for us, greatly appreciated....Hugs

<Matsumura_Clan@...> wrote: Channeling Bias May Explain

Leflunomide Link to Interstitial Lung Disease

NEW YORK (Reuters Health) May 30 - The risk of developing interstitial lung

disease (ILD) is increased among patients with rheumatoid arthritis (RA)

treated with leflunomide, according to findings published in the May issue

of Arthritis and Rheumatism. However, the association may be the result of

channeling of high-risk patients to leflunomide.

" Spontaneous reports of ILD in patients with RA treated with leflunomide, a

disease-modifying antirheumatic drug (DMARD), have been appearing recently, "

write Dr. Samy Suissa and colleagues from McGill University Health Center,

Montreal, Quebec, Canada.

To investigate, the researchers examined data on 62,734 RA patients who had

been treated with a DMARD. In a nested case-control design, each case of

serious ILD requiring hospitalization was matched to 100 controls to

estimate adjusted rate ratios (RRs) of serious ILD associated with DMARD

use.

Seventy-four patients were hospitalized because of serious ILD, which

corresponded to a rate of 8.1 per 10,000 patients per year. The use of

leflunomide was associated with an increased risk of ILD (adjusted RR 1.9).

The risk of ILD associated with leflunomide was not increased among patients

with no previous methotrexate use and no history of ILD (RR 1.2). The risk

was elevated among the remaining subjects (RR 2.6). Patients who had a

history of ILD were nearly twice as likely to have been prescribed

leflunomide as any other DMARD

" The increased risk of ILD in the patients treated with leflunomide appears

to be due to a channeling bias, where patients with a history of ILD may

have been preferentially prescribed leflunomide rather than methotrexate on

the assumption that, in contrast to methotrexate, no lung toxicity was

associated with leflunomide, " Dr. Suissa's team explains.

They conclude that for patients with no history of methotrexate use and no

existing ILD, leflunomide confers no excess risk of ILD.

Arthritis Rheum 2006;54:1435-1439.

http://www.medscape.com/viewarticle/533435

Not an MD

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org

May 31, 2006

,

No, this does not mean that people on MTX are at HIGH risk for ILD; however,

ILD or MTX pneumonitis is a well-described side effect of MTX therapy.

Arava (leflunomide) has not been used to treat RA for nearly as long as MTX,

so the authors are trying to ascertain the risk of ILD as a side effect of

Arava.

The risk of ILD is increased in patients with RA who use MTX. The risk of

ILD is increased in patients who use Arava. But what are the reasons for the

risk and how high is the risk in each case?

" Channeling bias " means that there is bias built into the patient sample in

question - the patient sample is not random (physicians choose certain

DMARDs for certain patients for various reasons). In this case, the authors

are guessing that, for example, patients with pre-existing lung disease (who

are at higher risk of developing drug-induced ILD) were given Arava instead

of MTX because the risk of MTX-induced ILD is well-known. The physicians

were doing the right thing in avoiding MTX in those cases, but some learned

is that Arava carries an ILD risk, too; however, Arava might have looked

worse statistically than it actually is.

Not an MD

I'll tell you where to go!

Mayo Clinic in Rochester

http://www.mayoclinic.org/rochester

s Hopkins Medicine

http://www.hopkinsmedicine.org

Re: [ ] NEWS - Channeling bias may explain Arava link to

interstitial lung disease

> , thank you for this article very informative. Question????? Does

> this article infer that those of us who use MTX have a high risk for ILD?

> To me the 2nd to last paragraph indicates so...Please clarify if you

> can....Thanks for all that you do for us, greatly appreciated....Hugs

>

> <Matsumura_Clan@...> wrote: Channeling Bias May Explain

> Leflunomide Link to Interstitial Lung Disease

>

> NEW YORK (Reuters Health) May 30 - The risk of developing interstitial

> lung

> disease (ILD) is increased among patients with rheumatoid arthritis (RA)

> treated with leflunomide, according to findings published in the May issue

> of Arthritis and Rheumatism. However, the association may be the result of

> channeling of high-risk patients to leflunomide.

>

> " Spontaneous reports of ILD in patients with RA treated with leflunomide,

> a

> disease-modifying antirheumatic drug (DMARD), have been appearing

> recently, "

> write Dr. Samy Suissa and colleagues from McGill University Health Center,

> Montreal, Quebec, Canada.

>

> To investigate, the researchers examined data on 62,734 RA patients who

> had

> been treated with a DMARD. In a nested case-control design, each case of

> serious ILD requiring hospitalization was matched to 100 controls to

> estimate adjusted rate ratios (RRs) of serious ILD associated with DMARD

> use.

>

> Seventy-four patients were hospitalized because of serious ILD, which

> corresponded to a rate of 8.1 per 10,000 patients per year. The use of

> leflunomide was associated with an increased risk of ILD (adjusted RR

> 1.9).

>

> The risk of ILD associated with leflunomide was not increased among

> patients

> with no previous methotrexate use and no history of ILD (RR 1.2). The risk

> was elevated among the remaining subjects (RR 2.6). Patients who had a

> history of ILD were nearly twice as likely to have been prescribed

> leflunomide as any other DMARD

>

> " The increased risk of ILD in the patients treated with leflunomide

> appears

> to be due to a channeling bias, where patients with a history of ILD may

> have been preferentially prescribed leflunomide rather than methotrexate

> on

> the assumption that, in contrast to methotrexate, no lung toxicity was

> associated with leflunomide, " Dr. Suissa's team explains.

>

> They conclude that for patients with no history of methotrexate use and no

> existing ILD, leflunomide confers no excess risk of ILD.

>

> Arthritis Rheum 2006;54:1435-1439.

>

> http://www.medscape.com/viewarticle/533435

>

May 31, 2006

But what is the ratio of people developing ILD without MTX or Arava?

I have ILD but have never used MTX or Arava, but my rheumy is talking about

starting it this month. I usually end up with pneumonia once or twice a year as

it is, the thought of this happening more often scare me. I do take Humeri,

Predisone,lexapro and Ultraset for RA. in WI

<Matsumura_Clan@...> wrote: