Analysis of daily activity data from implanted cardiac defibrillators: The minimum clinically important difference and relationship to mortality/life expectancy

Background: Daily activity is a potentially important measure for assessing prognosis in individuals with chronic heart failure (CHF), and few studies have investigated the prognostic value of daily activity measurement. The present study sought to determine whether there is an association between daily activity and mortality/mean life expectancy as predicted by the Seattle Heart Failure Model (SHFM), and to provide an estimate of the anchor-based minimum clinically important difference (MCID) for daily activity measured by single-axis accelerometers in implanted cardiac defibrillators. Methods: This study utilized a retrospective chart review of 102 medical records of patients with CHF and Medtronic? implanted cardiac defibrillators (ICDs). Mean daily activity was calculated for a two week period prior to both a baseline and follow-up routine clinical visit. Clinical characteristics from the baseline clinic visit were used for calculating SHFM estimates of mean life expectancy, 1-year mortality, and 5-year mortality. A five-point global rating scale was scored based on documented clinician impression, patient self-report, and laboratory and cardiographic tests for determining the MCID. Results: There was a moderate correlation between baseline daily activity and each of the SHFM prognostic indicators: 1-year mortality (r = 0.36, p < 0.001, 5-year mortality (r = 0.40, p < 0.001), and life expectancy (r = 0.43, p < 0.001). The MCID for a decline in daily activity was approximately 0.5 hours and was approximately 1.0 hours for improvement in daily activity. Conclusions: Although previous re- search has established the short-term predictive value of ICD-measured daily activity for CHF-related clinical events, no prior study has examined the longer-term prognostic value of ICD-based daily activity. The results of the present study suggest that low daily activity, as recorded by ICDs in patients with CHF, should prompt a more formal evaluation of prognosis using the SHFM. Furthermore, changes of 0.5 to 1.0 hours of activity per day appear to be clinically mean- ingful.

Interventions to improve daily activity in individuals with COPD and CHF: A systematic review

Introduction: The purpose was to systematically review the literature regarding interventions to improve daily activity in individuals with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF). Methods: Articles found by searching CINAHL Plus Full-Text, PubMed, and PsycINFO databases were included in the review if the study examined the effect of exercise- and/or psychosocial-based interventions on daily activity in individuals with COPD or CHF. Article selection, data extraction, and evaluation of methodological rigor and quality were performed by two independent reviewers. Nine articles for COPD and seven articles for CHF met the inclusion criteria and were used in this review. Results: Only four of nine studies in COPD and two of seven studies in CHF resulted in improvement in daily activity, and of those, all but one study included a psychosocial-based intervention. Improvements in daily activity did not occur concurrently with changes in other outcomes such as exercise performance, quality of life, functional status, or anxiety/depression in COPD or CHF. Conclusions: Exercise-based interventions serve a limited, if any, role in improving daily activity in individuals with COPD and CHF. Disrupting the cycle of inactivity and deconditioning requires more than just addressing the deconditioning aspect of this cycle. Psychosocial-based interventions are a promising, but under-investigated, intervention.