Ace Inhibitor / Angiotensin Receptor Blocker Use and Persistence Among Members with Coronary Artery Disease at High Risk for Coronary Events

The member’s persistence or medication possession ratio (MPR) for ACE inhibitor or ARB prescriptions during the measurement year.

Individuals with 0% MPR will be defined as those who did not fill any prescriptions for ACE or ARB.

Note: Members may switch between ACE inhibitors and ARB drugs

Time Window: 6 month period prior to measurement year to the measurement year. Of note, the 6 month period prior to the measurement year is needed to identify new ACE/ARB users and the measurement year is used to calculate MPR.

Step 1: Check if the member received at least one prescription of ACE/ARB in the measurement year. If no prescription had been received set MPR = 0 and TERMINATE PROGRAM. Otherwise proceed to Step 2.

Of note, this step would identify members who did not receive any ACE/ARB at all during the measurement year as members with MPR = 0.

Step 2: Check if the members received a least one prescription of ACE/ARB during the 6 month period prior to the beginning of the measurement year. If YES, then this patient is Not a new user of ACE/ARB and set the New_User flag = 0. If NO, then this patient is a new user of ACE/ARB medication and set the New_User flag = 1.

Of note, this step would differentiate new versus continuous ACE/ARB user.

Step 3: If patient is a new user (New_User flag = 1) then set START_DATE as the date of service (DOS) in which the first ACE/ARB prescription is filled and set PRIOR_SUPPLY = 0.

If START_DATE > 3/31 then drop the member from the analysis.

Of note, this step would allow the denominator time frame for the new user to be the difference in days between the first prescription of ACE/ARB and the end of the measurement year. In addition, this would also drop new users who filled the first prescription after 3/31.

Step 4: If patient is NOT a new user (New_User flag = 0) then set START_DATE the first day of the measurement year (i.e., January 1st) .

Of note, this step would set the measurement period of a continuous user as the first date of the measurement period.

Step 5: If patient is NOT a new user (New_User flag = 0) then set LAST_DATEi = the date of the last ACE/ARB prescription in the 6 month period prior to the start of the measurement year and DAY_SUPPLYi = day supply of this prescription.

Check if LAST_DATEi + DAY_SUPPLYi > first date of the measurement year.

If YES then PRIOR_SUPPLY = DAY_SUPPLYi - (First date of the measurement year – LAST_DATEi + 1); else PRIOR_SUPPLY = 0;

Of note, this step would take care of the case in which a prescription for ACE/ARB filled prior to the first date of the measurement year spilled over into the current measurement year.

Step 6: Identify the last prescription of ACE/ARB given during the measurement year and set the date of this prescription as LAST_DATEe and DAY_SUPPLYe = day supply of this prescription;

Check if LAST_DATEe + DAY_SUPPLYe > last date of the measurement year.

If Yes then LAST_SUPPLY = (last date of the measurement year - LAST_DATEe + 1)

If No then LAST_SUPPLY = DAY_SUPPLYe;

Of note, this step would take care of the case in which the prescription for ACE/ARB filled spilled over the current measurement year.

Step 7: Identify all the prescriptions of ACE/ARB given during the measurement year, except for the last prescription (i.e., P1, P2, …, Pn-1).

MPR = PRIOR_SUPPLY + ? total day supply of Pn-1 + LAST_SUPPLY
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(Last date of measurement year – START_DATE + 1)

Of note, the maximum MPR is 100%. If the calculated MPR is > 100% it will be capped at 100%.