The drug refill gap can help identify a patient who fails to fill a prescription for a long-term medication. It can be used as a screening measure of a patient's drug adherence.


The drug refill gap is the number of contiguous months during the year that the patient did not have an outpatient refill for the medication.



• A 1 month gap was no refills during the calendar month.

• There seem to be actually 2 different measures. The first would be the total number of months during the year with no drug refills. The second would be the number of sequential months without a drug refill.



(1) No need to refill, because the prescription from the previous month would cover the current month.

(2) The patient was hospitalized >= 10 days during the month.



• This is a relatively crude measure that would apply to a patient taking a medication for an extended period with refillable monthly prescription. The advantages are that it is simple and cheap.

• A person going to more than 1 pharmacy for refills would give false positive readings.

• The monitor would work best for a person on a fairly constant regimen for a long period. Multiple changes in a drug regimen or a fluctuating course with extended remissions would make use of this monitor difficult.

• This would detect a person who had stopped taking the drug entirely, but would be insensitive to the patient taking the drug intermittently.


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