@article {516131,
	title = {Patient Activity and Survival Following Implantable Cardioverter-Defibrillator Implantation: The ALTITUDE Activity Study},
	journal = {J Am Heart Assoc},
	volume = {4},
	number = {5},
	year = {2015},
	month = {2015 May 15},
	abstract = {BACKGROUND: Physical activity data are collected automatically by implantable cardioverter-defibrillators (ICDs). Though these data potentially provide a quantifiable and easily accessible measure of functional status, its relationship with survival has not been well studied.

METHODS AND RESULTS: Patients enrolled in the Boston Scientific LATITUDE remote monitoring system from 2008 to 2012 with ICDs were eligible. Remote monitoring data were used to calculate mean daily activity at baseline (30 to 60 days after implantation), and longitudinally. Cox regression was used to examine the association between survival and increments of 30 minutes/day in both (1) mean baseline activity and (2) time-varying activity, with both adjusted for demographic and device characteristics. A total of 98 437 patients were followed for a median of 2.2 years (mean age of 67.7{\textpm}13.1 years; 71.7\% male). Mean baseline daily activity was 107.5{\textpm}66.2 minutes/day. The proportion of patients surviving after 4 years was significantly higher among those in the most versus least active quintile of mean baseline activity (90.5\% vs. 50.0\%; log-rank P value, ,
	keywords = {Activities of Daily Living, Aged, Aged, 80 and over, Arrhythmias, Cardiac, Boston, Defibrillators, Implantable, Female, Follow-Up Studies, Humans, Longitudinal Studies, Male, Middle Aged, Motor Activity, Survival Analysis, Time Factors, Treatment Outcome},
	issn = {2047-9980},
	doi = {10.1161/JAHA.115.001775},
	author = {Kramer, Daniel B and Mitchell, Susan L and Monteiro, Joao and Jones, Paul W and Normand, Sharon-Lise and Hayes, David L and Reynolds, Matthew R}
}
