The CUSUM Slope Equals Observed Minus Expected Mortality and Can Be Visualized by a "Slope-Meter"

Ruyun Jin; Mansen Wang; Lian Wang; Gary L Grunkemeier

doi:10.1016/j.athoracsur.2022.05.022

The CUSUM Slope Equals Observed Minus Expected Mortality and Can Be Visualized by a "Slope-Meter"

Ann Thorac Surg. 2022 Sep;114(3):640-642. doi: 10.1016/j.athoracsur.2022.05.022. Epub 2022 May 30.

Authors

Ruyun Jin¹, Mansen Wang², Lian Wang², Gary L Grunkemeier²

Affiliations

¹ Center for Cardiovascular Analytics, Research and Data Science (CARDS), Providence Heart Institute, Providence Research Network, Portland, Oregon. Electronic address: ruyun.jin@gmail.com.
² Center for Cardiovascular Analytics, Research and Data Science (CARDS), Providence Heart Institute, Providence Research Network, Portland, Oregon.

PMID: 35654166
DOI: 10.1016/j.athoracsur.2022.05.022

Abstract

We present an additional advantage of the Risk-Adjusted CUSUM (RA-CUSUM), namely, that its slope can be quantified and is in fact equivalent to Observed (O) minus Expected (E) mortality. That is, the height of the RA-CUSUM is the O minus E deaths, which measures performance since the start of the series, and the slope of the RA-CUSUM is the O minus E mortality which measures performance during a chosen interval. We present a useful graphical tool (Slope-Meter) to allow approximation of this mortality difference by the viewer.