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.
where:
• 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.
Exclusions:
(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.
Limitations:
• 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.
