; and (iv) treat each reference in this paragraph to the product determined under subparagraph (B) for a period and risk category as a reference to the ratio determined under such subparagraph for a group, period, and risk category. (5) Performance categories described The performance categories described in this paragraph are the following: (A) Potentially-avoidable complications The performance category of complications (referred to in this section as potentially-avoidable complications ) that, with respect to items and services furnished to an individual entitled to benefits under part A in an applicable hospital, meet all of the following requirements: (i) The complication occurs during the stay of the individual and was not present at the time of the admission of such individual to such hospital as an inpatient. (ii) The complication is a harmful event (such as a surgical complication) or an acute illness (such as an infection or an acute exacerbation of underlying chronic disease). (iii) The complication is potentially avoidable with adequate care and treatment. (iv) The complication is not a natural progression of the underlying illnesses of the individual that are present on admission of such individual to such hospital. (v) The complication may be reasonably construed as related to the care rendered during the stay of the individual at the hospital. (B) Potentially-avoidable readmissions (i) In general The performance category of readmissions (referred to in this section as potentially-avoidable readmissions ) of individuals entitled to benefits under part A to any hospitals following a discharge (referred to in this section as an initial discharge ) of such individuals to an applicable hospital if the initial discharge and readmission involved satisfy all of the following requirements: (I) The readmission of the individual could reasonably have been prevented by— (aa) the provision of appropriate care during the episode of care ending in such initial discharge that was consistent with accepted standards