Fall 2016: Step Test

Step Test makes operations less costly.

Daniel Rubin, M.D.

Chicago Medicine 

About Dan

Daniel Rubin is an anesthesiologist working on utilizing the step/activity in mobile phones to quantify a patients functional status prior to non-cardiac surgery.  Functional status is the best measure we have to help identify patients that need more cardiac testing prior to surgery, however, no good quantitative tool exists to help quantify it.  


He has experience in app development, (DACC incident reporting system) and as an anesthesiologist understands peri-operative testing and assessment of cardiac function prior to surgery.


What’s Dan trying to solve?

Every year there are over 14 million doctor’s visits for pre-operative evaluations prior to surgical procedures.1  Conservative estimates show that overuse of cardiac stress tests prior to surgical procedures affects up to 190,000 patients a year leading to excess cost of up to $180 million just in patients enrolled in medicare.2  Numerous medical societies including the American College of Cardiology and American Society of Anesthesiologists have prioritized decreasing utilization of this expensive test prior to surgical procedures.3


What’s the plan?

Step Test takes activity data from patient’s smartphones, ihealth (iOS) S health (android) fitbit and others, to provide a clinician an empiric and quantitative assessment of a patient’s functional status.  The smartphone app data is typically stored for up to 6 months and can give physicians information such as steps climbed, average walking speed, maximum walking speed reached, maximum sustained walking speed and other variables.  Empiric data provided by the phone rather than simply asking the patient.  When presented to clinicians this smartphone data can better differentiate between patients that require costly stress testing and those that don’t.


How would this work?

Imagine a patient, Bob, presenting for surgery.  His activity is limited and he has some risk factors of coronary artery disease and his primary medical doctor is unsure if bob needs more testing prior to surgery.  His doctor asks him some questions about his activity level, but he isn’t sure and it isn’t clear if he has an adequate functional status or not.  If Bob had the mobile application, then he would be able to use it to help clarify his need for testing and potentially avoid an expensive and stressful test prior to his procedure.


Prior to surgery patients undergo a pre-operative evaluation to identify if further testing is necessary.  A patient’s functional status is a measure of their ability to perform basic needs and activities of daily living such as walking up a flight of stairs or walking at a pace of 4mph.  Cardiac conditions, particularly coronary artery disease and heart failure, can limit a patient’s ability to perform these normal tasks.  In the most recent national guidelines for cardiac evaluation prior to non-cardiac surgery functional status can determine if a cardiac stress test is necessary prior to a procedure.4  Patients unable to achieve a certain level of functional status may be sent for stress testing.   Currently, there is no quantitative measurement available to calculate a patients functional status.  

How does the App Challenge help with this great idea?

IT Services staff Fritz Anderson and Cornelia Bailey built an iOS app based on Dan's clinical needs for pre-operative patient evaluation. Dan will test the efficacy of his app in an IRB-approved study later in 2017. 

Dr. Rubin presented the Step Test app during the May Grand Rounds of the Department of Anesthesiology.