Schatz et al derived a scale based on long-term use of beta-agonists by a patient with asthma. This can help identify a patient with poorly-controlled asthma who may benefit from more aggressive management. The authors are from Kaiser-Permanente Medical Care Program, University of Pennsylvania and Harvard School of Public Health.


Typical beta-agonist dispensed: albuterol



(1) A person with poorly controlled asthma will take more puffs of a beta-agonist and use more canisters per year. Therefore, canister usage can serve as an estimate of long-term asthma control.

(2) There are 200 puffs per canister.

(3) The canister is used until it is completely empty.

(4) The pharmacy records reflect all of the canisters used by the patient.

Number of Canisters Used Per Year

Estimated Number of Puffs Per Day (Average)

Level of Control

0 to 2

0 to 1

1 (good)

3 to 6

2 to 3


7 to 12

4 to 7


>= 13

>= 8

4 (poor)



• It might be nice to identify these patients without waiting a year. A shorter interval could be annualized, although this might introduce bias. The highest use level would average over 1 canister per month.

• It is possible that a different sized canister could be used.


Puffs Per Year

How Long a Canister Lasts

Level of Control

<= 400

6 months to 1 year


600 to 1200

2 to 6 months


1400 to 2400

1 to 2 months


>= 2600

less than a month



Assuming that canister use is rounded up or down:


Puffs Per Year

Level of Control

< 500 (2.49 canisters with 200 puffs)


500 to 1299


1300 to 2499


>= 2500



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