Results Summary

What was the research about?

Asthma is a health problem that can make it hard to breathe. In Harris County, Texas, African-American adults with asthma die at twice the rate of white adults with asthma. Reducing asthma triggers at home, such as dust and chemical odors, can help patients manage asthma symptoms.

In this study, the research team wanted to learn if enhanced care with or without home visits helped African-American patients manage their asthma. Enhanced care included a doctor’s visit at a clinic to test for allergies, information on asthma triggers, and an asthma care plan. For patients who had home visits, a home visit team checked for asthma triggers. Then this team created a specific plan to improve asthma control, such as use of special pillow covers or safer pest control products. The research team compared patients who had home visits with those who didn’t have them.

What were the results?

After one year, patients with home visits had a greater reduction in emergency room, or ER, trips than patients without home visits. Patients with and without home visits didn’t differ in asthma control, quality of life, number of symptom-free days, or hospital stays for asthma.

Compared with the start of the study, after one year, patients with and without home visits

  • Had improved asthma control and quality of life and more symptom-free days
  • Were less likely to have ER visits or be hospitalized for asthma

Who was in the study?

The study included 263 African-American adults who had poorly controlled asthma. All lived in Harris County, which includes most of Houston. The average age was 50, and 75 percent were women.

What did the research team do?

The research team assigned patients to one of two groups by chance. Patients in both groups received enhanced clinical care. Patients in one group also received five home visits. The home visit team included an environmental home assessor, a nurse practitioner, and a community health worker, or CHW. The CHWs worked with the patients to implement the individual asthma control plan developed based on the first home visit. Patients who had home visits also received information about how to manage their asthma.

Patients completed surveys when they joined the study and again 6 and 12 months later.

Patients with asthma, a social worker, a doctor, and advocacy groups gave input during the study.

What were the limits of the study?

Fewer patients with home visits completed the study than patients without home visits. Results may have differed if more patients with home visits had completed the study. The study didn’t look at how well enhanced clinical care worked compared with usual asthma care. As a result, the team doesn’t know if the changes were because of enhanced clinical care or something else.

Future research could continue to look at ways to help African-American adults manage their asthma.

How can people use the results?

Clinics can use these results when considering ways to help African-American patients manage asthma.

Final Research Report

View this project's final research report.

More About This Research

Peer-Review Summary

Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.

The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments. 

Peer reviewers commented and the researchers made changes or provided responses. Those comments and responses included the following:

  • The reviewers suggested that the improvements observed in both groups in the study may have resulted from regression to the mean, since the study recruited only people with poorly controlled asthma, and asthma severity fluctuates over time. The researchers said they had considered this possibility and ran analyses to evaluate whether participants had been recruited during asthma exacerbations. The researchers explained that patients were generally recruited from databases where symptoms of poorly controlled asthma were recorded months before they enrolled patients in the study. The researchers considered that patients may have been more likely to enroll in the study if they were struggling with their symptoms when contacted. So, the researchers examined the patients’ asthma control scores and spirometry data from baseline to the last follow-up to look for evidence of an exacerbation at study entry. The researchers did not find evidence that participants experiencing an exacerbation were more likely to enter the study, but the researchers said that in future studies they will assess this possibility at enrollment.
  • The reviewers commented that when the researchers compare their results with those of other studies, they should note that other studies included patients who had less severe asthma. The researchers agreed that in general the severity of asthma in their patients allowed for greater improvement than would be expected in studies that recruited patients with mild asthma. They explained that their eligibility criteria allowed not only for patients with very poorly controlled asthma but also patients who had better control but suffered regular acute crises leading to hospitalizations or repeated emergency department visits. By reviewing enrollment information for the study participants, the researchers were able to ascertain that 92.4 percent of participants could be categorized as having very poorly controlled asthma based on accepted clinical criteria, and 6.5 percent of participants met criteria for not well-controlled asthma. Finally, the researchers identified three patients as having well-controlled asthma at baseline, and the researchers posited that these three participants were probably enrolled because their asthma was not well controlled at screening but by baseline had improved.
  • The reviewers noted that the two study groups showed differences in baseline characteristics and asked the researchers to include any such differences in their multivariate models. The researchers responded by reanalyzing their outcomes after including emergency department use and employment status, two areas of significant difference between the study groups, in the models. The researchers reported that use of a portable heater was another characteristic that had significant baseline differences, but they did not include this variable in the model because it was not related to the primary outcome and had considerable missing data.

Conflict of Interest Disclosures

View the COI disclosure form.

Peer-Review Summary

Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.

The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments. 

Peer reviewers commented and the researchers made changes or provided responses. Those comments and responses included the following:

  • The reviewers suggested that the improvements observed in both groups in the study may have resulted from regression to the mean, since the study recruited only people with poorly controlled asthma, and asthma severity fluctuates over time. The researchers said they had considered this possibility and ran analyses to evaluate whether participants had been recruited during asthma exacerbations. The researchers explained that patients were generally recruited from databases where symptoms of poorly controlled asthma were recorded months before they enrolled patients in the study. The researchers considered that patients may have been more likely to enroll in the study if they were struggling with their symptoms when contacted. So, the researchers examined the patients’ asthma control scores and spirometry data from baseline to the last follow-up to look for evidence of an exacerbation at study entry. The researchers did not find evidence that participants experiencing an exacerbation were more likely to enter the study, but the researchers said that in future studies they will assess this possibility at enrollment.
  • The reviewers commented that when the researchers compare their results with those of other studies, they should note that other studies included patients who had less severe asthma. The researchers agreed that in general the severity of asthma in their patients allowed for greater improvement than would be expected in studies that recruited patients with mild asthma. They explained that their eligibility criteria allowed not only for patients with very poorly controlled asthma but also patients who had better control but suffered regular acute crises leading to hospitalizations or repeated emergency department visits. By reviewing enrollment information for the study participants, the researchers were able to ascertain that 92.4 percent of participants could be categorized as having very poorly controlled asthma based on accepted clinical criteria, and 6.5 percent of participants met criteria for not well-controlled asthma. Finally, the researchers identified three patients as having well-controlled asthma at baseline, and the researchers posited that these three participants were probably enrolled because their asthma was not well controlled at screening but by baseline had improved.
  • The reviewers noted that the two study groups showed differences in baseline characteristics and asked the researchers to include any such differences in their multivariate models. The researchers responded by reanalyzing their outcomes after including emergency department use and employment status, two areas of significant difference between the study groups, in the models. The researchers reported that use of a portable heater was another characteristic that had significant baseline differences, but they did not include this variable in the model because it was not related to the primary outcome and had considerable missing data.

Conflict of Interest Disclosures

Project Information

Winifred J. Hamilton, MS, PhD
Baylor College of Medicine
$2,352,903
10.25302/04.2021.AS.130805887

Key Dates

52 months
December 2013
March 2020
2013
2020

Study Registration Information

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Last updated: October 20, 2021