This variable identifies the co-insurance percentage that drugs on the tier are subject to during the post out-of-pocket threshold (catastrophic) phase of the Part D benefit.
This variable was new in 2007. This field is only populated if the Medicare-defined Post Threshold Cost Shares do not apply. Plans that use a co-payment amount rather than a coinsurance percentage will not have a value in this field; see instead the corresponding co-payment variable called (POST_OOPT_COPAY_AMT). The catastrophic coverage phase is also referred to as the post-out-of-pocket threshold phase for the Part D benefit.
The CCW constructs the Plan Characteristics File from information submitted by Part D plan sponsors to CMS’s Health Plan Management System (HPMS). Employer and National Program of All-inclusive Care for the Elderly (PACE) plans are waived from reporting Plan Benefit Package information.
For those plans that did not report, the value of this variable will be blank.
Source: CMS (HPMS Files)