disease) and seven separate evaluation sets: disability, employment, quality of life, functional capacity, treatment outcomes, severity of impairment, and comorbidities.
Unique terms were identified in each subject area to yield a wide array of results. Strategy parameters included limiting the search to human subjects, the English language, and publication years from 1980 to October 2009. This time period was chosen to ensure the most relevant studies were captured that examined employment capability of populations with cardiovascular conditions. For those evaluation sets reviewing functional capacity, treatment outcomes, and severity of impairment, the parameters were further limited to results published from 2004 to focus on the most recent medical and science literature.
The secondary strategy of the literature review involved reviewing key articles’ cited references. Additionally, the PubMed database was searched using Boolean logic with the main term of cardiovascular and key terms related to employment, that is, return to work. Studies were published from 1966 to 2009. Other literature supplemented the body of relevant research supporting the committee’s research and report writing, resulting from targeted searches performed on an ad hoc basis to answer specific research questions.
A tiered category system was developed to refine results. A rigorous review of study titles and abstracts determined which studies met the inclusion criteria. Each study was coded according to the corresponding tier (see Box B-1). The primary search strategy yielded 85 studies in Tier 1; after removing duplicate articles produced from the primary search strategy, the secondary strategy yielded an additional 88 studies, for a total of 173 Tier 1 studies. To refine these results, the parameters were further limited to focus on studies published between 2004 and 2009, producing the final results of the literature review of 35 Tier 1 articles. Table B-1 provides a more detailed review of the final Tier 1 studies.
An additional 674 articles were identified as Tier 2 articles, which were reviewed to potentially inform the broader parameters affecting functional capacity of populations with cardiovascular diseases leading to disability. These parameters include relative quality of life (with specific measurements for health-related quality of life), comorbid conditions, gender comparisons, and assessments of treatments for cardiovascular conditions or associated conditions that may lead to disability or impairment. The committee determined the Tier 2 studies were not immediately relevant to the statement of work, and few of the studies were included in the final report. The remaining studies were categorized as Tier 3 and 4 studies. Tier 3 stud-