Patients who shared in decisions regarding their asthma treatment were significantly more likely to adhere to ICS and other controller therapy, and also to LABA medications, than patients who experienced either usual care or who received care management in which the clinician played the primary role in choosing the treatment regimen. By virtue of both (1) their greater fill/refill adherence and (2) the pattern of their regimen choices, patients in the SDM group also acquired a significantly higher average daily dose of asthma controller medication (a larger number of beclomethasone canister equivalents) than either patients under usual care or active control patients. Additionally, patients who shared in making treatment decisions had significantly better clinical outcomes on all six measures—asthma-related quality of life, asthma health care utilization, use of rescue medication, lung function, and the likelihood of well-controlled asthma—compared with those receiving usual care. Although the SDM approach, and the behavioral and regimen changes it induced, were not associated with significantly better clinical outcomes compared with the CDM approach, the differences were consistently in a direction favoring SDM on both objectively measured and patient-reported outcomes. Furthermore, the clinician decision model only resulted in significantly better clinical outcomes compared with usual care on four of the six clinical outcomes, and not in significantly less SABA use or a higher FEV1:FEV6 ratio. Only among patients in the SDM group was SABA use (the only clinical outcome available for the second follow-up year) significantly lower than that of usual care in follow-up Year 2.
The greater advantage of the SDM than the CDM model over usual care, as well as the greater persistence of its effectiveness in reducing SABA use, support a treatment preference for the SDM approach. However, a rigorous, long-term cost-benefit analysis is required to determine whether these clinical benefits are accompanied by cost savings that offset the cost of the CDM or the additional cost of the SDM intervention.
There was no evidence that the SDM approach resulted in a significant proportion of patients avoiding corticosteroids or electing inadequate doses. In fact, patient involvement resulted in higher proportions receiving the highest-dose fluticasone (220 μg) over the highest-dose beclomethasone (80 μg), and the combination ICS-LABA over separate preparations. Both tendencies appeared to be due to the greater convenience of the regimen (i.e., the need for fewer puffs of fluticasone [220 μg/d] than beclomethasone [80 μg/d] to achieve an equipotent dose), and the convenience of a single inhaler in the case of the combination preparation. Without the patient's active involvement, the CDM care managers tended to choose the formulary-recommended ICS and separate ICS and LABA preparations.
Significance of Findings
An SDM approach is consistent with the concept of patient-centered care, and this study demonstrates that it is an important component with significant potential to not only change patient behavior through increased adherence, but also to improve clinical outcomes. The present findings have significant implications for asthma treatment and research, and potentially for the treatment of a wide range of other chronic conditions.
The findings also provide previously unavailable information on the average degree of clinical improvement, on a range of outcome measures, that is associated with a specific average increase in the cumulative annual ICS dose. This finding may help in evaluating the clinical importance of other interventions directed at improving medication adherence that may lack some or all of the clinical outcome measures obtained in the present trial.
The observation of a mean improvement in the quality of life score of 0.40 points, attributable to the SDM model, is less than the putative 0.50 minimal clinically important difference on that measure (40
). However, questions exist regarding the methodology used to establish that minimal clinically important difference value (41
). The fact that the SDM group reported significantly higher quality of life at follow up, and that more than 70% of the group experienced a score improvement of greater than 0.50 points, is additional evidence that the clinical benefits of the intervention were evident to the patients.
Concern with the quality of clinician–patient communication dates back at least 4 decades (43
). Until now, observational studies have been the norm. Few controlled experimental studies have been conducted of modifications in communication around the treatment decision process, as distinct from other aspects of clinician–patient communication, and none of those that have been conducted concerned asthma. Most have emphasized one-time or acute treatment decisions, rather than the ongoing decisions associated with chronic conditions. Previous research also has generally focused on patient satisfaction, and has shown little evidence of significantly changing patient behavior or improving clinical outcomes. Furthermore, lack of assessment of the quality of the interventions, as delivered, has severely limited the interpretability of the largely negative trials (16
Attributing the observed adherence, regimen potency, and clinical benefits to the patients' active participation in their treatment decisions is justified because the SDM and CDM interventions were identical in all respects, except the treatment decision process. This experimental difference was also reflected in the perception of those in the SDM group that they had a greater role in the treatment decisions than did the patients in the CDM group. Previous controlled trials of SDM have given insufficient attention to the choice of the control condition. Joosten and colleagues' review (18
) did not consider the appropriateness of the control condition as a design criterion; most studies reviewed simply compared their intervention to the current standard of care. Without an active control for features of the intervention other than the treatment decision process (e.g., providing patient education), it is difficult to know the extent to which any positive results are attributable specifically to the patient's involvement in the treatment choice. The contribution of the BOAT study is enhanced by the existence of such a control, which allowed the elucidation of the unique contribution of the shared decision process itself.
Asthma care management.
The target population of patients with poorly controlled asthma was a specific subset of patients with asthma within a very large managed health care system that had a long-standing commitment to high-quality asthma care, education of patients with asthma, and physician adherence to asthma treatment guidelines, and that, at some sites, offered asthma care management as an optional part of usual medical care. Virtually all of these patients had medication benefits with modest copayments that varied with the provisions of their insurance plans. Nevertheless, in the baseline year, these patients had acquired only about one-third of the days' supply of medication that had been prescribed for them, and were experiencing frequent symptoms and activity limitations. Nearly one-fifth were not using an asthma controller at all. Our findings reveal that care management using a clinician decision model was clearly beneficial in terms of medication adherence and many clinical outcomes, and suggest that the likelihood of achieving the hoped-for benefits, and their magnitude, is increased by specifically involving the patient in the choice of treatment.
Need for ongoing reinforcement.
The fall-off in asthma controller adherence/acquisition that was observed during follow-up Year 2 in both care management conditions is not surprising, and suggests that further follow up and reinforcement may be important to sustain the benefits of a shared decision process and of care management in general. For both models, the interventions typically occurred very early in follow-up Year 1, with no external reinforcement of the intervention processes after the patients' 9-month follow-up intervention phone calls.
Primary care providers and other clinicians at KP who may have seen patients subsequently had no access to the intervention materials, and hence were very unlikely to have used a comparable shared treatment decision approach. Patients in both care management conditions were also less likely than patients under usual care to have asthma-related medical visits during follow-up Year 1, which would also reduce the opportunity for reinforcement.
The fall-off in adherence may also suggest that, having experienced a clinical benefit in Year 1, patients began to “step down” therapy on their own. There is a need for further investigation into the pattern and causes of the decline in medication adherence over time, and whether periodic review by a care manager or physician can sustain both adherence and clinical benefits.
Intervention cost versus benefits.
Compared with usual care, in follow-up Year 1 the SDM care management intervention increased the total days' supply of controller medication acquired by the patient by an average of 77 days and by 9.6 beclomethasone canister equivalents, increased the quality of life score by 0.4 points, decreased asthma-related physician visits per year by 0.4 visits, reduced albuterol acquisition by 1.6 canister equivalents, increased the FEV1:FEV6 ratio by an average of 2.8 percentage points, and doubled the likelihood of having well controlled asthma. Although the SDM intervention required a per-patient investment of $174 for care manager time, and resulted in some increase in cost to the patient and health care system for medications, it also resulted in decreased costs for asthma-related provider visits. The study was not powered to detect specific differences in the more costly ED visits and hospitalizations; hence, any cost savings in this regard are unknown, and should be the focus of future research.
The SDM intervention included all four defining features of the SDM model (mutual information sharing, expressing treatment preferences, discussing the options, and agreeing on treatment). The study design tested the hypothesized benefits of this model in a randomized, controlled trial with a very strong active, as well as a passive, control group. Care managers' adherence to their respective intervention protocols was objectively assessed, and confirmed the fidelity of intervention delivery, and it was documented that the interventions resulted in differing perceptions of patients' own influence on the treatment decisions.
Other strengths include the use of objective measures of medication acquisition and refill adherence and health care utilization, available for all patients during follow up, high-quality spirometry, and multiple validated patient-centered measures.
As an initial efficacy trial, this study was not powered to detect differences in ED visits or hospitalization rates—the most costly types of utilization; hence, a true cost–benefit analysis was not performed. The results of this study are also limited to adult patients; it remains to be determined whether the effects of a shared decision process can be generalized to pediatric patients (i.e., to treatment decisions made by parents on their child's behalf). Finally, in settings in which different treatment options have more pronounced differential cost implications for patients (e.g., non–managed care organizations), or in which asthma management guidelines support different patterns of medication usage (e.g., greater use of combination products), the priorities of adult patients may be more or less consonant with clinician recommendations than was observed here.
Although pharmacy dispensing data were obtained for both follow-up years, the inability to continue active follow-up and to extract health care utilization data through follow-up Year 2 is a modest limitation. However, even a 1-year follow up of multiple behavioral, clinical, and health care utilization outcomes greatly exceeds the duration of most previous studies.
An SDM approach to the selection of asthma pharmacotherapy, in the context of asthma care management, is efficacious in improving both medication adherence and clinical outcomes. An appropriately powered study to determine the cost-effectiveness of this approach is warranted, as are further studies of the effectiveness of this approach in patients with other poorly controlled chronic diseases and in both younger and older patients.