Statistics Colloquium
October 26 (Fri) 11 a.m.
Alavi Commons Room, 6625 Everett Tower

Longitudinal daily activity patterns in individuals with chronic heart failure: derivation and association with prognosis and clinical characteristics

Michael J. Shoemaker, PT, DPT, PhD, GCS1
Amy B. Curtis, PhD, MPH2
Rajib Paul, PhD2
Michael G. Dickinson, MD, FACC3
Alyssa Polso, BS1

1Grand Valley State University Department of Physical Therapy
2Western Michigan University
3Spectrum Health Frederik Meijer Heart and Vascular Institute

PURPOSE: The purpose of the present study was to determine whether individuals with chronic heart failure (CHF) demonstrate distinct patterns of daily activity and whether these patterns are associated with prognosis and clinical characteristics.

METHODS: Secondary analysis of previously reported retrospective data from 102 patients with CHF. Available data included daily activity measured by Medtronic® implanted cardiac defibrillators, Seattle Heart Failure Model (SHFM ) prognostic estimates, and clinical characteristics. Longitudinal daily activity patterns were derived using time series cluster analysis. The association between daily activity pattern grouping, SHFM prognosis, and clinical characteristics were analyzed using one-way ANOVA with planned contrasts and chi square analysis for continuous and categorical variables, respectively.

RESULTS: The derived patterns of daily activity were low, moderately low, moderately high, and high daily activity, and were based upon a mean (standard deviation) daily activity of 35.5 (21.7), 112.0 (20.3), 198.6 (22.0), and 340.7 (66.1) minutes per day, respectively. No patterns of increasing or decreasing daily activity were identified. Statistically significant main effects and repeated contrasts were found across daily activity pattern groupings: older age, lower left ventricular ejection fraction, and worse SHFM prognosis were associated with low activity levels. Statistically significant differences for categorical variables were also observed: female gender, ischemic etiology, and higher New York Heart Association functional class were associated with low activity levels.

CONCLUSIONS: Low activity levels should prompt a formal evaluation of prognosis. Given the apparent stability of daily activity over time, clinicians should not expect significant changes in daily activity patterns without specifically targeted interventions.

All statistics students are expected to attend.


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