These data are used by CMS to calculate the Home Health Resource Group's (HHRGs) case-mix index, which in turn is used in the home health PPS.
Case-mix variables: Two of the case-mix variables, the HHRGs and the percent of Medicare patients, had positive marginal costs.
We used the outcome episode as the unit of analysis and removed outcome episodes longer than 60 days and episodes beginning with a resumption of care rather than a SOC assessment--longer episodes because the HHRG can change for the subsequent payment period, and resumptions of care because the HHRG calculated from resumption of care OASIS information may not be the HHRG derived at SOC on which payment is based.
Table 2 shows the pre-PPS and PPS changes in the HHRG distribution and visits per episode.
With adjustment for the shift in the HHRG distribution, total visits per episode were 16.6 percent lower in the PPS compared with the pre-PPS period (based on outcome, not payment, episodes).
Since the wound item affects the HHRG classification and payment amount, the importance of accurate reporting on wounds increased substantially after PPS implementation.
([dagger]) Identical OASIS item used for HHRG determination (nine items in this model).
Under PPS, a prospectively determined per-episode payment rate is case-mix adjusted using 80 mutually exclusive Home Health Resource Groups (HHRGs).
We used the PPS HHRGs to control for patient case mix in the visit analyses.
Eighty HHRGs are formed by taking all combinations of one level from each dimension (e.g., C0-F2-S3).