Cardiovascular Disease, Heart Failure: Scope of Literature

Summary

This review sought to collect and interpret the evidence on home telehealth for management of people with heart failure. We looked at 3 areas:

  • Patients: How is home telehealth used in treating people with heart failure?  Do patients like it?  How clinically effective is it?
  • Providers: What is the impact of home telehealth on health human resources?  What are the roles of nurses, general practitioners, and specialists in its delivery?  How do providers characterize their experiences with home telehealth?
  • System: How is home telehealth incorporated into the care continuum?  What is the economic impact of incorporating home telehealth into heart failure care?  What policies need to be in place for home telehealth to be successful?

In order to answer these questions, we conducted a systematic search for literature published from 2005 to 2010.  This search retrieved 23 studies that met our inclusion criteria.  The quality of the evidence was strong.  A final search for publications from 2011 to 2012 found 9 additional studies.  Though findings from these studies were incorporated into the review, be aware that material from the 2011-2012 period was screened and analyzed in a slightly different way than the studies retrieved in our original search.

 

Details

Number and Location

A search of literature published from 2005-2010 located 23 studies of home telehealth for managing heart failure. Three were multi-part studies (Scalvini et al., 2005a,b; Soran et al., 2008, 2010; Wakefield et al., 2008a,b, 2009). Scalvini et al. (2005a) presented results from a large controlled study of a home telemonitoring system. A non-comparative analysis of the intervention group data alone appeared in Scalvini et al. (2005b). Different outcomes from the same intervention were found in Soran et al. (2008) and Soran et al. (2010). Another cluster of publications presented different outcomes (Wakefield et al., 2008b; Wakefield et al., 2009) and a sub-analysis (Wakefield et al., 2008a) of a single intervention.

Over half of the studies were located in the USA, with the eastern states particularly strongly represented. Eight were located in Western Europe. Only 1 study was carried out in Canada (Woodend et al., 2008). Location was not reported by Whitten et al. (2009).

A final search for material published from 2011-2012 found 9 additional studies that met our inclusion criteria and filled gaps left by the first rounds of searching (Acosta et al., 2011; Almond et al., 2011; Boyne et al., 2012; Dickerson et al., 2011; Koehler et al., 2011; Lemay et al., 2011; Sohn et al., 2012; Stampehl et al., 2012; Wade et al., 2011). These studies were analyzed in a slightly different way than the studies retrieved in our original search, and their findings were incorporated into this review in a limited fashion. For more details, please see Methods.

Study Design

The Oxford 2011 Levels of Evidence were used to assess the strength of the evidence base.[1] Studies were placed on a scale running from Level 1,[2] considered the highest level of evidence, through to Level 5.[3] Levels are based primarily on study design. Studies were also assigned scores for quality of execution and reporting. Low execution/reporting scores resulted in downgrading.

The Oxford 2011 Levels of Evidence are intended to provide guidance rather than absolute judgments, and do not obviate the need for careful appraisal of local needs and context. The quality of studies within a given level can vary, as can their applicability to select populations. Furthermore, this system is not suitable for all forms of assessment. In the text that follows, the Oxford 2011 Levels of Evidence are used only when discussing clinical outcomes.

The evidence base for home telehealth in management of heart failure was strong. Of the 23 studies retrieved, roughly three-quarters were Level 2 evidence.[4] These studies used randomization, concurrent comparison groups, and prospective measurement of exposure and outcomes. The remaining studies were unevenly divided between Levels 3 and 4.[5] The majority of these were retrospective designs or single-group studies with multiple pre- and post-measurements.

Quality was generally very high; almost all of the studies received moderate to strong scores for execution and reporting. Particularly strong were Balk et al. (2008), Bowles et al. (2009), Dansky et al. (2008), Mortara et al. (2006), Soran et al. (2008), Wakefield et al. (2008b), and Weintraub (2010).

Hospitalization statistics – number, time to, and length of – were the most frequently reported outcomes, with over half of the studies addressing one or more of those listed above. Emergency services use was another commonly measured system outcome. Frequently measured patient outcomes included quality of life and morbidity/mortality, each of which was addressed in just under half of the studies found.

Approximately half of the studies lasted 3 months or less, with the remaining studies roughly evenly divided between 6 and 12 months. The number of participants enrolled was typically between 200 and 400 (range 32-826).

And on the qualitative side . . .Rahimpour et al. (2008) was the only qualitative article on cardiovascular disease that was retrieved. This study took place in Sydney, Australia, and looked at patients with chronic obstructive pulmonary disease (COPD) and/or congestive heart failure (CHF).

 

Population Characteristics: Demographics

Many of the studies were conducted with older adults, with the mean age ranging from 60-70 years old (Balk, 2008; Bondmass, 2007; Chaudry et al., 2010; Cleland et al., 2005; Kulshreshtha et al., 2010; Piotrowicz et al., 2009; Schmidt et al., 2008; Schwarz et al., 2008; Wakefield et al., 2008a, b, 2009; Weintraub, 2010; Woodend et al., 2008). In 8 studies, the average age of participants was over 70 years old (Bowles et al., 2009; Dansky et al., 2008; Dar et al., 2009; Gambetta et al., 2007; Hudson et al., 2005; Ramaekers et al. 2009; Soran et al., 2008, 2010; Whitten et al., 2009). Myers et al. (2006) and Soran et al. (2008, 2010) limited their enrollment to those over 60 years. In Kashem et al. (2008), the average patient was much younger – approximately 55 years old – than was typical of this group of studies. Patient age was not reported in Scalvini et al. (2005a, b).

Although there was significant variation within the studies retrieved, samples tended to include more males than females. This was the case in 11 studies (Balk et al., 2008; Dar et al., 2009; Piotrowicz et al., 2009; Ramaekers et al., 2009; Cleland et al., 2005; Kashem et al., 2008; Kulshreshtha et al., 2010; Mortara et al., 2008; Wakefield et al., 2008b, 2009; Weintraub et al., 2010; Woodend et al., 2008). Piotrowicz et al. (2009) and Wakefield et al. (2008b, 2009) were especially skewed; the percentage of males in their intervention and control groups fell between 85% and 99%. Sex distribution was roughly even in 6 studies (Chaudhry et al., 2009; Gambetta et al., 2007; Hudson et al., 2005; Myers et al., 2006; Schmidt et al., 2008; Schwarz et al., 2008) and unreported in 2 (Dansky et al., 2008; Scalvini et al., 2005a, b). The remaining 4 studies were female-dominated (Bondmass, 2007; Bowles et al., 2009; Soran et al., 2008, 2010; Whitten et al., 2009).

Socioeconomic data were reported in very few studies (Bondmass, 2007; Chaudhry et al., 2009; Ramaekers et al., 2009; Schwarz et al., 2008).

Population Characteristics: Clinical Characteristics

Eligibility criteria for nearly all studies required the patient to have been hospitalized for heart failure within the preceding 12 months.

Disease severity or functional status was reported in 11 studies. In those using New York Heart Association (NYHA) classifications, most patients fell into class II or III (Chaudhry et al., 2009; Soran et al., 2008, 2010; Gambetta et al., 2007; Kashem et al., 2008; Mortara et al., 2008; Bondmass, 2007; Piotrowicz et al., 2009; Woodend et al., 2008; Weintraub, 2010; Wakefield et al., 2008b, 2009). The majority of other studies, while not providing a NYHA classification, described participants as suffering from minimal to moderately severe cardiac disease that limited activities of daily living and resulted in symptoms such as pain due to angina, dyspnea, palpitations and fatigue.

A few studies required a minimum level of disease burden in their inclusion criteria. Schmidt et al. (2008), Woodend et al. (2008), Myers et al., (2006), and Bondmass (2007) required a NYHA classification of level III or IV. These individuals experienced higher disease burden and may represent a patient subpopulation at higher risk of clinical deterioration.

Co-morbidities were reported in 16 cases (Balk, 2008; Bondmass, 2007; Bowles et al., 2009; Chaudhry et al., 2010; Cleland et al., 2005; Dar et al., 2009; Kulshreshtha et al., 2010; Mortara et al., 2008; Myers et al., 2006; Piotrowicz et al., 2009; Schmidt et al., 2008; Schwarz et al., 2008; Soran et al., 2010; Wakefield et al., 2008; Weintraub, 2010; Woodend et al., 2008). Most participants in these studies were living with multiple chronic diseases. The most commonly cited co-morbidities were diabetes (Balk, 2008; Bowles et al., 2009; Chaudhry et al., 2010; Cleland et al., 2005; Dar et al., 2009; Kulshreshtha et al., 2010; Piotrowicz et al., 2009; Schwarz et al., 2008; Weintraub, 2010) and hypertension (Balk, 2008; Cleland et al., 2005; Dar et al., 2009; Kulshreshtha et al., 2010; Schwarz et al., 2008; Weintraub, 2010).

Other co-morbidities included chronic lung disease (Balk, 2008; Cleland et al., 2005; Schwarz et al., 2008), stroke (Cleland et al., 2005; Piotrowicz et al., 2009; Schwarz et al., 2008), coronary artery disease or previous coronary artery bypass surgery (Chaudry et al., 2010; Woodend et al., 2008; Schwarz et al., 2008), previous myocardial infarction (Cleland et al., 2005; Dar et al., 2009), depression (Bowles et al., 2009; Kulshreshtha et al., 2010). Chronic renal failure was common in Dar et al. (2009), in which it afflicted two-thirds of the participants.


[1] For a comprehensive overview of this system, please refer to Jeremy Howick, Iain Chalmers, Paul Glasziou, Trish Greenhalgh, Carl Heneghan, Alessandro Liberati, Ivan Moschetti, Bob Phillips, and Hazel Thornton. “Explanation of the 2011 Oxford Centre for Evidence-Based Medicine (OCEBM) Levels of Evidence (Background Document)”.
Oxford Centre for Evidence-Based Medicine.
http://www.cebm.net/index.aspx?o=5653

[2] Systematic reviews of randomized trials; n-of-1 trials.

[3] Mechanism-based reasoning.

[4] Balk et al., 2008; Bondmass, 2007; Bowles et al., 2009; Chaudhry et al., 2010; Cleland et al., 2010; Dansky et al., 2008; Dar et al., 2009; Kashem et al., 2008; Kulshreshtha et al., 2010; Piotrowicz et al., 2009; Ramaekers et al., 2009 Mortara et al., 2009; Schwarz et al., 2008; Soran et al., 2008, 2010; Wakefield et al., 2008a, 2008b, 2009; Weintraub et al., 2010; Woodend et al., 2008.

[5] Respectively: Gambetta et al., 2007; Schmidt et al., 2008; and Hudson et al., 2005; Myers et al., 2006; Scalvini et al, 2005a, 2005b; Whitten et al., 2009.

 

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