CONTEXT: A recent systematic review of home-based, multi-trigger, multicomponent interventions with an environmental focus showed their effectiveness in reducing asthma morbidity among children and adolescents. These interventions included home visits by trained personnel to assess the level of and reduce adverse effects of indoor environmental pollutants, and educate households with an asthma client to reduce exposure to asthma triggers. The purpose of the present review is to identify economic values of these interventions and present ranges for the main economic outcomes (e.g., program costs, benefit-cost ratios, and incremental cost-effectiveness ratios). EVIDENCE ACQUISITION: Using methods previously developed for Guide to Community Preventive Services economic reviews, a systematic review was conducted to evaluate the economic efficiency of home-based, multi-trigger, multicomponent interventions with an environmental focus to improve asthma-related morbidity outcomes. A total of 1551 studies were identified in the search period (1950 to June 2008), and 13 studies were included in this review. Program costs are reported for all included studies; cost-benefit results for three; and cost-effectiveness results for another three. Information on program cost was provided with varying degrees of completeness: six of the studies did not provide a list of components included in their program cost description (limited cost information), three studies provided a list of program cost components but not a cost per component (partial cost information), and four studies provided both a list of program cost components and costs per component (satisfactory cost information). EVIDENCE SYNTHESIS: Program costs per participant per year ranged from $231-$14,858 (in 2007 U.S.$). The major factors affecting program cost, in addition to completeness, were the level of intensity of environmental remediation (minor, moderate, or major), type of educational component (environmental education or self-management), the professional status of the home visitor, and the frequency of visits by the home visitor. Benefit-cost ratios ranged from 5.3-14.0, implying that for every dollar spent on the intervention, the monetary value of the resulting benefits, such as averted medical costs or averted productivity losses, was $5.30-$14.00 (in 2007 U.S.$). The range in incremental cost-effectiveness ratios was $12-$57 (in 2007 U.S.$) per asthma symptom-free day, which means that these interventions achieved each additional symptom-free day for net costs varying from $12-$57. CONCLUSIONS: The benefits from home-based, multi-trigger, multicomponent interventions with an environmental focus can match or even exceed their program costs. Based on cost-benefit and cost-effectiveness studies, the results of this review show that these programs provide a good value for dollars spent on the interventions.

CONTEXT: Asthma exacerbations are commonly triggered by exposure to allergens and irritants within the home. The purpose of this review was to evaluate evidence that interventions that target reducing these triggers through home visits may be beneficial in improving asthma outcomes. The interventions involve home visits by trained personnel to conduct two or more components that address asthma triggers in the home. Intervention components focus on reducing exposures to a range of asthma triggers (allergens and irritants) through environmental assessment, education, and remediation. EVIDENCE ACQUISITION: Using methods previously developed for the Guide to Community Preventive Services, a systematic review was conducted to evaluate the evidence on effectiveness of home-based, multi-trigger, multicomponent interventions with an environmental focus to improve asthma-related morbidity outcomes. The literature search identified over 10,800 citations. Of these, 23 studies met intervention and quality criteria for inclusion in the final analysis. EVIDENCE SYNTHESIS: In the 20 studies targeting children and adolescents, the number of days with asthma symptoms (symptom-days) was reduced by 0.8 days per 2 weeks, which is equivalent to 21.0 symptom-days per year (range of values: reduction of 0.6 to 2.3 days per year); school days missed were reduced by 12.3 days per year (range of values: reduction of 3.4 to 31.2 days per year); and the number of asthma acute care visits were reduced by 0.57 visits per year (interquartile interval: reduction of 0.33 to 1.71 visits per year). Only three studies reported outcomes among adults with asthma, finding inconsistent results. CONCLUSIONS: Home-based, multi-trigger, multicomponent interventions with an environmental focus are effective in improving overall quality of life and productivity in children and adolescents with asthma. The effectiveness of these interventions in adults is inconclusive due to the small number of studies and inconsistent results. Additional studies are needed to (1) evaluate the effectiveness of these interventions in adults and (2) determine the individual contributions of the various intervention components.