Shared treatment decision making improves adherence and outcomes in poorly controlled asthma

Abstract

Rationale: Poor adherence to asthma controller medications results in poor treatment outcomes.

Objectives: To compare controller medication adherence and clinical outcomes in 612 adults with poorly controlled asthma randomized to one of two different treatment decision-making models or to usual care.

Methods: In shared decision making (SDM), nonphysician clinicians and patients negotiated a treatment regimen that accommodated patient goals and preferences. In clinician decision making, treatment was prescribed without specifically eliciting patient goals/preferences. The otherwise identical intervention protocols both provided asthma education and involved two in-person and three brief phone encounters.

Measurements and main results: Refill adherence was measured using continuous medication acquisition (CMA) indices-the total days' supply acquired per year divided by 365 days. Cumulative controller medication dose was measured in beclomethasone canister equivalents. In follow-up Year 1, compared with usual care, SDM resulted in: significantly better controller adherence (CMA, 0.67 vs. 0.46; P < 0.0001) and long-acting beta-agonist adherence (CMA, 0.51 vs. 0.40; P = 0.0225); higher cumulative controller medication dose (canister equivalent, 10.9 vs. 5.2; P < 0.0001); significantly better clinical outcomes (asthma-related quality of life, health care use, rescue medication use, asthma control, and lung function). In Year 2, compared with usual care, SDM resulted in significantly lower rescue medication use, the sole clinical outcome available for that year. Compared with clinician decision making, SDM resulted in: significantly better controller adherence (CMA, 0.67 vs. 0.59; P = 0.03) and long-acting beta-agonist adherence (CMA, 0.51 vs. 0.41; P = 0.0143); higher cumulative controller dose (CMA, 10.9 vs. 9.1; P = 0.005); and quantitatively, but not significantly, better outcomes on all clinical measures.

Conclusions: Negotiating patients' treatment decisions significantly improves adherence to asthma pharmacotherapy and clinical outcomes. Clinical trials registered with www.clinicaltrials.gov (NCT00217945 and NCT00149526).

Figure 1.

Outline of intervention protocols, with unique features of each highlighted.

Figure 2.

Case progress through the Better Outcomes of Asthma Treatment (BOAT) study: identification, eligibility determination, initial assessment, randomization, intervention, and follow up. ¹Patients were identified as potentially eligible based on their recent hospitalization or emergency department visit and a medication ratio of ±0.50, indicating an overuse of rescue medication. ²Not contactable includes patients whose primary care physicians (PCPs) were not notified, PCP did not respond, PCP did not assent, letters were not sent/received, or calls were not successfully completed. ³Nonscreenable patients were not screened for multiple reasons, including disinterest in participating in the study. ⁴Includes persons who passively refused by failing to keep two or more enrollment appointments. ⁵Reasons for ineligibility include failure to meet spirometry criterion and other psychosocial and medical prerandomization exclusion criteria (e.g., drug rehabilitation or currently receiving asthma care management, etc.). ⁶Excludes five postrandomization exclusions for previously undiscovered bahavioral/mental health problems: shared decision making (SDM), n = 1; clinician decision making (CDM), n = 4.

Figure 3.

Group differences in pharmacy outcomes. (A) Group differences in controller medication acquisition for each study period. Controller medications include inhaled corticosteroids (ICS), leukotriene modifiers, and theophylline, and exclude long-acting β-agonists (LABAs) and oral prednisone. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline CMA and the balancing variables. The 95% confidence intervals (CIs) are shown. Group differences and 95% CIs for controller CMA values at follow-up Year 1: shared decision making (SDM)-usual care (UC) = 0.21 (95% CI, 0.13–0.28); SDM–clinician decision making (CDM) = 0.08 (95% CI, 0.01–0.15); CDM-UC = 0.13 (95% CI, 0.05–0.20). At follow-up Year 2: SDM-UC = 0.03 (95% CI, −0.05–0.11); SDM-CDM = 0.04 (95% CI, −0.04–0.12); CDM-UC = −0.01 (95% CI, −0.09–0.07). The number of patients per group at each time point: SDM, n = 204; CDM, n = 204; UC, n = 204. (B) Group differences in ICS canister equivalents for each study period. Controller medications include inhaled corticosteroids and leukotriene modifiers, and exclude theophylline, LABAs and oral prednisone. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline ICS canister equivalents and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for ICS canister equivalents at follow-up Year 1: SDM-UC = 5.8 (95% CI, 4.5–7.0); SDM-CDM = 1.8 (95% CI, 0.57–3.1); CDM-UC = 3.9 (95% CI, 2.6–5.2). At follow-up Year 2: SDM-UC = 2.5 (95% CI, 1.2–3.8); SDM-CDM = 1.4 (95% CI, 0.04–2.7); CDM-UC = 1.1 (95% CI, −0.18–2.4). The number of patients per group at prerandomization and follow-up Year 2 is: SDM, n = 204; CDM, n = 202; UC, n = 204; and at follow-up Year 1 is: SDM, n = 204; CDM, n = 202; UC, n = 203. (C) Group differences in LABA acquisition, among those on a LABA, for each study period. LABA medications include fluticasone-salmeterol 100, fluticasone-salmeterol 250, fluticasone-salmeterol 500, and formeterol. Prerandomization values are unadjusted and follow-up values are adjusted for baseline CMA and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for LABA CMA at follow-up Year 1: SDM-UC = 0.11 (95% CI, 0.02–0.20); SDM-CDM = 0.09 (95% CI, 0.02–0.17); CDM-UC = 0.01 (95% CI, −0.08–0.10). At follow-up Year 2: SDM-UC = 0.11 (95% CI, 0.01–0.20); SDM-CDM = 0.09 (95% CI, 0.01–0.18); CDM-UC = 0.01 (95% CI, −0.08–0.11). The number of patients per group at each time point is: prerandomization, SDM, n = 40; CDM, n = 44; UC, n = 52; follow-up Year 1: SDM, n = 112; CDM, n = 108; UC, n = 59. (D) Group differences in short-acting β-agonist (SABA) use for each study period. For each patient, the number of canister-equivalents is the mean of the sum of all SABAs dispensed to that patient, each weighted relative to one canister of a standard albuterol canister. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline albuterol canister equivalents and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for SABA use at follow-up Year 1: SDM-UC = −1.6 (95% CI, −2.5 to −0.78); SDM-CDM = −0.73 (95% CI, −1.6 to 0.12); CDM-UC = −0.89 (95% CI, −1.7 to −0.05). At follow-up Year 2: SDM-UC = −1.2 (95% CI, −2.1 to −0.24); SDM-CDM = −0.91 (95% CI, −1.9–0.04); CDM-UC = −0.28 (95% CI, −1.2–0.67). The number of patients per group at each time point is: SDM, n = 204; CDM, n = 204; UC, n = 204.

Figure 3.

Group differences in pharmacy outcomes. (A) Group differences in controller medication acquisition for each study period. Controller medications include inhaled corticosteroids (ICS), leukotriene modifiers, and theophylline, and exclude long-acting β-agonists (LABAs) and oral prednisone. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline CMA and the balancing variables. The 95% confidence intervals (CIs) are shown. Group differences and 95% CIs for controller CMA values at follow-up Year 1: shared decision making (SDM)-usual care (UC) = 0.21 (95% CI, 0.13–0.28); SDM–clinician decision making (CDM) = 0.08 (95% CI, 0.01–0.15); CDM-UC = 0.13 (95% CI, 0.05–0.20). At follow-up Year 2: SDM-UC = 0.03 (95% CI, −0.05–0.11); SDM-CDM = 0.04 (95% CI, −0.04–0.12); CDM-UC = −0.01 (95% CI, −0.09–0.07). The number of patients per group at each time point: SDM, n = 204; CDM, n = 204; UC, n = 204. (B) Group differences in ICS canister equivalents for each study period. Controller medications include inhaled corticosteroids and leukotriene modifiers, and exclude theophylline, LABAs and oral prednisone. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline ICS canister equivalents and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for ICS canister equivalents at follow-up Year 1: SDM-UC = 5.8 (95% CI, 4.5–7.0); SDM-CDM = 1.8 (95% CI, 0.57–3.1); CDM-UC = 3.9 (95% CI, 2.6–5.2). At follow-up Year 2: SDM-UC = 2.5 (95% CI, 1.2–3.8); SDM-CDM = 1.4 (95% CI, 0.04–2.7); CDM-UC = 1.1 (95% CI, −0.18–2.4). The number of patients per group at prerandomization and follow-up Year 2 is: SDM, n = 204; CDM, n = 202; UC, n = 204; and at follow-up Year 1 is: SDM, n = 204; CDM, n = 202; UC, n = 203. (C) Group differences in LABA acquisition, among those on a LABA, for each study period. LABA medications include fluticasone-salmeterol 100, fluticasone-salmeterol 250, fluticasone-salmeterol 500, and formeterol. Prerandomization values are unadjusted and follow-up values are adjusted for baseline CMA and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for LABA CMA at follow-up Year 1: SDM-UC = 0.11 (95% CI, 0.02–0.20); SDM-CDM = 0.09 (95% CI, 0.02–0.17); CDM-UC = 0.01 (95% CI, −0.08–0.10). At follow-up Year 2: SDM-UC = 0.11 (95% CI, 0.01–0.20); SDM-CDM = 0.09 (95% CI, 0.01–0.18); CDM-UC = 0.01 (95% CI, −0.08–0.11). The number of patients per group at each time point is: prerandomization, SDM, n = 40; CDM, n = 44; UC, n = 52; follow-up Year 1: SDM, n = 112; CDM, n = 108; UC, n = 59. (D) Group differences in short-acting β-agonist (SABA) use for each study period. For each patient, the number of canister-equivalents is the mean of the sum of all SABAs dispensed to that patient, each weighted relative to one canister of a standard albuterol canister. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline albuterol canister equivalents and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for SABA use at follow-up Year 1: SDM-UC = −1.6 (95% CI, −2.5 to −0.78); SDM-CDM = −0.73 (95% CI, −1.6 to 0.12); CDM-UC = −0.89 (95% CI, −1.7 to −0.05). At follow-up Year 2: SDM-UC = −1.2 (95% CI, −2.1 to −0.24); SDM-CDM = −0.91 (95% CI, −1.9–0.04); CDM-UC = −0.28 (95% CI, −1.2–0.67). The number of patients per group at each time point is: SDM, n = 204; CDM, n = 204; UC, n = 204.

Figure 3.

Group differences in pharmacy outcomes. (A) Group differences in controller medication acquisition for each study period. Controller medications include inhaled corticosteroids (ICS), leukotriene modifiers, and theophylline, and exclude long-acting β-agonists (LABAs) and oral prednisone. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline CMA and the balancing variables. The 95% confidence intervals (CIs) are shown. Group differences and 95% CIs for controller CMA values at follow-up Year 1: shared decision making (SDM)-usual care (UC) = 0.21 (95% CI, 0.13–0.28); SDM–clinician decision making (CDM) = 0.08 (95% CI, 0.01–0.15); CDM-UC = 0.13 (95% CI, 0.05–0.20). At follow-up Year 2: SDM-UC = 0.03 (95% CI, −0.05–0.11); SDM-CDM = 0.04 (95% CI, −0.04–0.12); CDM-UC = −0.01 (95% CI, −0.09–0.07). The number of patients per group at each time point: SDM, n = 204; CDM, n = 204; UC, n = 204. (B) Group differences in ICS canister equivalents for each study period. Controller medications include inhaled corticosteroids and leukotriene modifiers, and exclude theophylline, LABAs and oral prednisone. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline ICS canister equivalents and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for ICS canister equivalents at follow-up Year 1: SDM-UC = 5.8 (95% CI, 4.5–7.0); SDM-CDM = 1.8 (95% CI, 0.57–3.1); CDM-UC = 3.9 (95% CI, 2.6–5.2). At follow-up Year 2: SDM-UC = 2.5 (95% CI, 1.2–3.8); SDM-CDM = 1.4 (95% CI, 0.04–2.7); CDM-UC = 1.1 (95% CI, −0.18–2.4). The number of patients per group at prerandomization and follow-up Year 2 is: SDM, n = 204; CDM, n = 202; UC, n = 204; and at follow-up Year 1 is: SDM, n = 204; CDM, n = 202; UC, n = 203. (C) Group differences in LABA acquisition, among those on a LABA, for each study period. LABA medications include fluticasone-salmeterol 100, fluticasone-salmeterol 250, fluticasone-salmeterol 500, and formeterol. Prerandomization values are unadjusted and follow-up values are adjusted for baseline CMA and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for LABA CMA at follow-up Year 1: SDM-UC = 0.11 (95% CI, 0.02–0.20); SDM-CDM = 0.09 (95% CI, 0.02–0.17); CDM-UC = 0.01 (95% CI, −0.08–0.10). At follow-up Year 2: SDM-UC = 0.11 (95% CI, 0.01–0.20); SDM-CDM = 0.09 (95% CI, 0.01–0.18); CDM-UC = 0.01 (95% CI, −0.08–0.11). The number of patients per group at each time point is: prerandomization, SDM, n = 40; CDM, n = 44; UC, n = 52; follow-up Year 1: SDM, n = 112; CDM, n = 108; UC, n = 59. (D) Group differences in short-acting β-agonist (SABA) use for each study period. For each patient, the number of canister-equivalents is the mean of the sum of all SABAs dispensed to that patient, each weighted relative to one canister of a standard albuterol canister. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline albuterol canister equivalents and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for SABA use at follow-up Year 1: SDM-UC = −1.6 (95% CI, −2.5 to −0.78); SDM-CDM = −0.73 (95% CI, −1.6 to 0.12); CDM-UC = −0.89 (95% CI, −1.7 to −0.05). At follow-up Year 2: SDM-UC = −1.2 (95% CI, −2.1 to −0.24); SDM-CDM = −0.91 (95% CI, −1.9–0.04); CDM-UC = −0.28 (95% CI, −1.2–0.67). The number of patients per group at each time point is: SDM, n = 204; CDM, n = 204; UC, n = 204.

Figure 3.

Group differences in pharmacy outcomes. (A) Group differences in controller medication acquisition for each study period. Controller medications include inhaled corticosteroids (ICS), leukotriene modifiers, and theophylline, and exclude long-acting β-agonists (LABAs) and oral prednisone. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline CMA and the balancing variables. The 95% confidence intervals (CIs) are shown. Group differences and 95% CIs for controller CMA values at follow-up Year 1: shared decision making (SDM)-usual care (UC) = 0.21 (95% CI, 0.13–0.28); SDM–clinician decision making (CDM) = 0.08 (95% CI, 0.01–0.15); CDM-UC = 0.13 (95% CI, 0.05–0.20). At follow-up Year 2: SDM-UC = 0.03 (95% CI, −0.05–0.11); SDM-CDM = 0.04 (95% CI, −0.04–0.12); CDM-UC = −0.01 (95% CI, −0.09–0.07). The number of patients per group at each time point: SDM, n = 204; CDM, n = 204; UC, n = 204. (B) Group differences in ICS canister equivalents for each study period. Controller medications include inhaled corticosteroids and leukotriene modifiers, and exclude theophylline, LABAs and oral prednisone. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline ICS canister equivalents and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for ICS canister equivalents at follow-up Year 1: SDM-UC = 5.8 (95% CI, 4.5–7.0); SDM-CDM = 1.8 (95% CI, 0.57–3.1); CDM-UC = 3.9 (95% CI, 2.6–5.2). At follow-up Year 2: SDM-UC = 2.5 (95% CI, 1.2–3.8); SDM-CDM = 1.4 (95% CI, 0.04–2.7); CDM-UC = 1.1 (95% CI, −0.18–2.4). The number of patients per group at prerandomization and follow-up Year 2 is: SDM, n = 204; CDM, n = 202; UC, n = 204; and at follow-up Year 1 is: SDM, n = 204; CDM, n = 202; UC, n = 203. (C) Group differences in LABA acquisition, among those on a LABA, for each study period. LABA medications include fluticasone-salmeterol 100, fluticasone-salmeterol 250, fluticasone-salmeterol 500, and formeterol. Prerandomization values are unadjusted and follow-up values are adjusted for baseline CMA and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for LABA CMA at follow-up Year 1: SDM-UC = 0.11 (95% CI, 0.02–0.20); SDM-CDM = 0.09 (95% CI, 0.02–0.17); CDM-UC = 0.01 (95% CI, −0.08–0.10). At follow-up Year 2: SDM-UC = 0.11 (95% CI, 0.01–0.20); SDM-CDM = 0.09 (95% CI, 0.01–0.18); CDM-UC = 0.01 (95% CI, −0.08–0.11). The number of patients per group at each time point is: prerandomization, SDM, n = 40; CDM, n = 44; UC, n = 52; follow-up Year 1: SDM, n = 112; CDM, n = 108; UC, n = 59. (D) Group differences in short-acting β-agonist (SABA) use for each study period. For each patient, the number of canister-equivalents is the mean of the sum of all SABAs dispensed to that patient, each weighted relative to one canister of a standard albuterol canister. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline albuterol canister equivalents and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for SABA use at follow-up Year 1: SDM-UC = −1.6 (95% CI, −2.5 to −0.78); SDM-CDM = −0.73 (95% CI, −1.6 to 0.12); CDM-UC = −0.89 (95% CI, −1.7 to −0.05). At follow-up Year 2: SDM-UC = −1.2 (95% CI, −2.1 to −0.24); SDM-CDM = −0.91 (95% CI, −1.9–0.04); CDM-UC = −0.28 (95% CI, −1.2–0.67). The number of patients per group at each time point is: SDM, n = 204; CDM, n = 204; UC, n = 204.

Figure 4.

Group differences in asthma-related quality of life, asthma-related health care utilization, and asthma control. (A) Group differences in asthma-related quality of life. The five-item Mini Asthma Quality of Life Questionnaire (MAQLQ) subscale is scored on a symptom scale of 0 (All of the time) to 7 (None of the time). Subscale items include: shortness of breath, bothered by coughing, chest tightness or heaviness, difficulty sleeping, and chest wheeze. Pre randomization values are unadjusted and follow-up values are adjusted for the baseline score and the balancing variables. 95% confidence intervals (CIs) are shown. Group differences and 95% CIs for MAQLQ score at follow-up Year 1 are: shared decision making (SDM)-usual care (UC) = 0.39 (95% CI, 0.18–0.60); SDM–clinician decision making (CDM) = 0.11 (95% CI, −0.11–0.32); CDM-UC = 0.28 (95% CI, 0.07–0.50). The number of patients per group with no missing values at either time point is SDM n = 182, CDM n = 180, UC n = 189. (B) Group differences in the annual rate of asthma-related health care utilization (visits/yr). Prerandomization values are unadjusted, and follow-up values are adjusted for baseline asthma-related health care utilization and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for medical visits at follow-up Year 1 are: SDM-UC = −0.36 (95% CI, −0.66 to −0.07); SDM-CDM = 0.01 (95% CI, −0.29–0.30); CDM-UC = −0.37 (95% CI, −0.67 to −0.07). The number of patients per group at each time point is: SDM, n = 204; CDM, n = 204; UC, n = 204. (C) Odds ratios of well controlled asthma at each time period. The usual care group was the referent value when estimating the odds for the SDM and CDM groups. The CDM group also served as the referent value for the SDM group. The Asthma Therapy Assessment Questionnaire (ATAQ) scale is from 0 (no control problems; “well controlled”) to 4 (four control problems). Well controlled asthma is based on an ATAQ score = 0. Pre-randomization odds ratios are unadjusted and follow-up odds ratios are adjusted for the baseline ATAQ score and the balancing variables. 95% CIs are shown. The number of patients per group with no missing values at either time point is: SDM, n = 182; CDM, n = 180; UC, n = 189.

Figure 4.

Group differences in asthma-related quality of life, asthma-related health care utilization, and asthma control. (A) Group differences in asthma-related quality of life. The five-item Mini Asthma Quality of Life Questionnaire (MAQLQ) subscale is scored on a symptom scale of 0 (All of the time) to 7 (None of the time). Subscale items include: shortness of breath, bothered by coughing, chest tightness or heaviness, difficulty sleeping, and chest wheeze. Pre randomization values are unadjusted and follow-up values are adjusted for the baseline score and the balancing variables. 95% confidence intervals (CIs) are shown. Group differences and 95% CIs for MAQLQ score at follow-up Year 1 are: shared decision making (SDM)-usual care (UC) = 0.39 (95% CI, 0.18–0.60); SDM–clinician decision making (CDM) = 0.11 (95% CI, −0.11–0.32); CDM-UC = 0.28 (95% CI, 0.07–0.50). The number of patients per group with no missing values at either time point is SDM n = 182, CDM n = 180, UC n = 189. (B) Group differences in the annual rate of asthma-related health care utilization (visits/yr). Prerandomization values are unadjusted, and follow-up values are adjusted for baseline asthma-related health care utilization and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for medical visits at follow-up Year 1 are: SDM-UC = −0.36 (95% CI, −0.66 to −0.07); SDM-CDM = 0.01 (95% CI, −0.29–0.30); CDM-UC = −0.37 (95% CI, −0.67 to −0.07). The number of patients per group at each time point is: SDM, n = 204; CDM, n = 204; UC, n = 204. (C) Odds ratios of well controlled asthma at each time period. The usual care group was the referent value when estimating the odds for the SDM and CDM groups. The CDM group also served as the referent value for the SDM group. The Asthma Therapy Assessment Questionnaire (ATAQ) scale is from 0 (no control problems; “well controlled”) to 4 (four control problems). Well controlled asthma is based on an ATAQ score = 0. Pre-randomization odds ratios are unadjusted and follow-up odds ratios are adjusted for the baseline ATAQ score and the balancing variables. 95% CIs are shown. The number of patients per group with no missing values at either time point is: SDM, n = 182; CDM, n = 180; UC, n = 189.

Figure 4.

Group differences in asthma-related quality of life, asthma-related health care utilization, and asthma control. (A) Group differences in asthma-related quality of life. The five-item Mini Asthma Quality of Life Questionnaire (MAQLQ) subscale is scored on a symptom scale of 0 (All of the time) to 7 (None of the time). Subscale items include: shortness of breath, bothered by coughing, chest tightness or heaviness, difficulty sleeping, and chest wheeze. Pre randomization values are unadjusted and follow-up values are adjusted for the baseline score and the balancing variables. 95% confidence intervals (CIs) are shown. Group differences and 95% CIs for MAQLQ score at follow-up Year 1 are: shared decision making (SDM)-usual care (UC) = 0.39 (95% CI, 0.18–0.60); SDM–clinician decision making (CDM) = 0.11 (95% CI, −0.11–0.32); CDM-UC = 0.28 (95% CI, 0.07–0.50). The number of patients per group with no missing values at either time point is SDM n = 182, CDM n = 180, UC n = 189. (B) Group differences in the annual rate of asthma-related health care utilization (visits/yr). Prerandomization values are unadjusted, and follow-up values are adjusted for baseline asthma-related health care utilization and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for medical visits at follow-up Year 1 are: SDM-UC = −0.36 (95% CI, −0.66 to −0.07); SDM-CDM = 0.01 (95% CI, −0.29–0.30); CDM-UC = −0.37 (95% CI, −0.67 to −0.07). The number of patients per group at each time point is: SDM, n = 204; CDM, n = 204; UC, n = 204. (C) Odds ratios of well controlled asthma at each time period. The usual care group was the referent value when estimating the odds for the SDM and CDM groups. The CDM group also served as the referent value for the SDM group. The Asthma Therapy Assessment Questionnaire (ATAQ) scale is from 0 (no control problems; “well controlled”) to 4 (four control problems). Well controlled asthma is based on an ATAQ score = 0. Pre-randomization odds ratios are unadjusted and follow-up odds ratios are adjusted for the baseline ATAQ score and the balancing variables. 95% CIs are shown. The number of patients per group with no missing values at either time point is: SDM, n = 182; CDM, n = 180; UC, n = 189.

Figure 5.

Group differences in lung function. (A) Group differences in percent predicted FEV₁ for each study period. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline percent predicted FEV₁ and the balancing variables. The 95% confidence intervals (CIs) are shown. Group differences and 95% CIs for percent predicted FEV₁ at follow-up Year 1 are: shared decision making (SDM)–usual care (UC) = 3.2 (95% CI, 0.87–5.4); SDM–clinician decision making (CDM) = 0.85 (95% CI, −1.4–3.1); CDM-UC = 2.3 (95% CI, 0.04–4.6). The number of patients per group with no missing values at either time point is: SDM, n = 165; CDM, n = 170; UC, n = 172. (B) Group differences in the ratio of FEV₁:FEV₆ for each study period. The ratio is expressed as a percentage. Prerandomization values are unadjusted, and follow-up values are adjusted for the baseline FEV₁:FEV₆ ratio and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for the ratio of FEV₁:FEV₆ at follow-up Year 1: SDM-UC = 1.9 (95% CI, 0.84–3.0); SDM-CDM = 0.92 (95% CI, −0.14–2.0); CDM-UC = 0.98 (95% CI, −0.07–2.0). The number of patients per group with no missing values at either time point is: SDM, n = 165; CDM, n = 170; UC, n = 172.

Figure 5.

Group differences in lung function. (A) Group differences in percent predicted FEV₁ for each study period. Prerandomization values are unadjusted, and follow-up values are adjusted for baseline percent predicted FEV₁ and the balancing variables. The 95% confidence intervals (CIs) are shown. Group differences and 95% CIs for percent predicted FEV₁ at follow-up Year 1 are: shared decision making (SDM)–usual care (UC) = 3.2 (95% CI, 0.87–5.4); SDM–clinician decision making (CDM) = 0.85 (95% CI, −1.4–3.1); CDM-UC = 2.3 (95% CI, 0.04–4.6). The number of patients per group with no missing values at either time point is: SDM, n = 165; CDM, n = 170; UC, n = 172. (B) Group differences in the ratio of FEV₁:FEV₆ for each study period. The ratio is expressed as a percentage. Prerandomization values are unadjusted, and follow-up values are adjusted for the baseline FEV₁:FEV₆ ratio and the balancing variables. The 95% CIs are shown. Group differences and 95% CIs for the ratio of FEV₁:FEV₆ at follow-up Year 1: SDM-UC = 1.9 (95% CI, 0.84–3.0); SDM-CDM = 0.92 (95% CI, −0.14–2.0); CDM-UC = 0.98 (95% CI, −0.07–2.0). The number of patients per group with no missing values at either time point is: SDM, n = 165; CDM, n = 170; UC, n = 172.