| Inclusion criteria (patients will be included if meeting all of the following) |
Ethnicity: All ethnic groups; Gender: Both men and women; Age (as of date of enrollment):
Body mass index 18.5–39.9 kg/m2; Suboptimally controlled asthma:
Documented history of high asthma-related emergency and/or inpatient encounters and/or high reliever medication usage: using relevant data in electronic health records, an enriched pool of potentially eligible patients who likely have uncontrolled, persistent asthma will be identified according to 1 or more of the following criteria:
at least 1 inpatient admission with a primary asthma diagnosis or a secondary asthma diagnosis accompanied by a primary asthma-related diagnosis during the past 12 months; at least 1 emergency visit with an asthma diagnosis during the past 6 months; at least 5 prescriptions for asthma medication filled during the past 6 months and at least 2 prescriptions for oral corticosteroids filled within the past 12 months; at least 12 canisters of short-acting beta-agonists in the past 12 months; at least 3 short-acting beta-agonist dispensing events during the past 12 months.
Physiological evidence of asthma with demonstrable reversibility of airway obstruction by spirometry, or a specialist's confirmation of asthma diagnosis based on chart review. As specified in our prior study [ 80], the airway obstruction reversibility criteria vary by individual depending upon smoking history and controller medication use and are as follows:
For smokers and nonsmokers who do not use controller medications regularly (≥4 days a week), reversibility is determined by an increase in FEV1 of ≥12% and ≥200 mL from baseline after inhalation of 4 puffs of albuterol. For current or ex-smokers taking controller medications, reversibility is determined by an increase in FEV1 of ≥8% and ≥200 mL from baseline after inhalation of 4 puffs of albuterol. No reversibility criteria apply to never smokers who regularly use controller medications.
Asthma Control Test: total score <20 or item score <3 for any of the first 4 questions regarding symptoms (3–6×/week or more), nighttime awakening (1×/week or more), interference with normal activity (at least some of the time), and rescue medication use for symptom relief (2–3×/week or more);
Kaiser member for ≥1 year; PCP approval of study screening; Able and willing to enroll and provide written informed consent, i.e., to meet the time and data collection requirements of the study, be randomized to 1 of 2 treatment arms, participate in follow-up for 6 months, and authorize extraction of relevant information from their medical records.
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| Exclusion criteria (patients will be excluded if meeting any of the following) |
| Medical history exclusions |
Primary diagnosis of intermittent asthma, defined as either seasonal asthma or (daytime asthma symptoms <2×/week and nocturnal symptoms <2×/month and no use of long-term control medications); Primary diagnosis of COPD (emphysema or chronic bronchitis) suggested by patient report of doctor diagnosis, spirometry, and smoking history; Previous diabetes (other than during pregnancy) or diabetes diagnosed as a result of fasting blood glucose or hemoglobin A1c levels obtained through study screening; Previous cardiovascular disease: e.g., coronary heart disease (myocardial infarction, angina pectoris, percutaneous coronary intervention, coronary artery bypass graft surgery), cerebrovascular disease (stroke, transient ischemic attack), peripheral vascular disease, heart failure, or aortic aneurysm; Diagnosis of cancer (other than non-melanoma skin cancer) that is/was active or treated with radiation or chemotherapy within the past 2 years; Inflammatory bowel disease, colostomy, malabsorption, or major gastrointestinal resection; Diagnosis of bipolar or psychotic disorder or hospitalization for psychological or emotional problems within the last 2 years; Diagnosis of a terminal illness and/or in hospice care.
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| Medication exclusions |
Current use of insulin or oral hypoglycemic agents; Use of oral corticosteroids >5 days/month on average; Current use of medications for treatment of psychosis or manic-depressive illness; Current use of prescription or non-prescription weight-loss products or any dietary/herbal supplements and unwillingness to stop taking them for the duration of the study.
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| Other exclusions |
Inability to speak, read, or understand English at the 6th-grade level or above; Inability to perform pulmonary function tests by spirometry in a consistent manner; DASH concordance indexa >60%; Unwillingness to modify current diet; Current/planned participation in another structured program that overtly focuses on diet and nutrition; Planning to undergo bariatric surgery during the study period; Actively attempting to lose weight or weight change >15 lbs during prior 3 months; Consumption of >21 alcoholic drinks per week, or >=6 drinks on 1 occasion twice or more per week, or an alcohol abuse disorder as determined by the Alcohol Use Disorders Identification Test; Currently pregnant, lactating, or planning to become pregnant during the study period; No longer a Kaiser patient or planning to transfer care out of Kaiser or to move out of the area during the study period; Family/household member of another study participant or of a study staff member; Currently enrolled or planning to enroll in another research study that would limit full participation in the study or confound the interpretation of the study's findings; Investigator discretion for clinical safety or protocol adherence reasons.
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