Letter Regarding Article by Galbreath et al, “Long-Term Healthcare and Cost Outcomes of Disease Management in a Large, Randomized, Community-Based Population With Heart Failure”
To the Editor:
We commend Dr Galbreath and colleagues on a well-designed study evaluating the impact of a disease management program on health status, utilization, and cost.1 There is, however, one extremely important point that requires comment. The authors indicate that the results of this study are generalizable because the “catchment” area spanned 70 000 mi2 in south Texas. This study has strong “internal validity,” but we would argue that the “external validity”2 of the findings will apply only to similar people, settings, treatments, and outcomes.3 Such a “generalizable” population would be one with a high level of baseline compliance with recommended treatment guidelines. In this study, the authors state that 77% of the patients were taking either an angiotensin-converting enzyme inhibitor or angiotensin receptor blockers at the time of enrollment, as compared with the 30% to 50% rate noted in other trials. This is not a trivial issue because drug therapy is a central part of recommended guidelines.3 The authors correctly noted that under circumstances of high adherence to guidelines “the value added by a disease management program will be more difficult to demonstrate.”
This factor alone may account for why no reductions in utilization or costs were realized in the study group when compared with the reference. Disease management by its very name implies that participants will be guided toward improving control of their condition. The mainstay of these programs is in bringing the individual and his or her physician in line with evidence-based practice guidelines. If individuals already adhere to self-management behaviors, then there is little gain to be expected from a disease management program.
Galbreath AD, Krasuski RA, Smith B, Stajduhar KC, Kwan MD, Ellis R, Freeman GL. Long-term healthcare and cost outcomes of disease management in a large, randomized, community-based population with heart failure. Circulation. 2004; 110: 3518–3526.
Linden A, Adams JL, Roberts N. Generalizing disease management program results: how to get from here to there. Manag Care Interface. 2004; 17: 38–45.
We agree with Drs Wilson and Linden that before applying a study’s results to one’s own patient population, the similarity between the patient groups must be carefully considered. Unlike previous studies that have evaluated the impact of disease management strategies in small populations of patients from a single hospital or health maintenance organization, we studied a large group of patients recruited from a wide spectrum of healthcare systems and demographics. We enrolled patients from large cities (San Antonio, Austin), from small towns (Beeville, Three Rivers), and from isolated rural settings in Texas. Although it could be argued that a ranch in south Texas is different from a dairy farm in New England, we again emphasize that this was a broadly heterogeneous population from a range of backgrounds. Thus, we feel justified in stating that our results are more generally applicable than those of less diverse previous studies.
We also agree with Wilson and Linden that disease management will have the greatest impact when there is substantial room for improvement in therapies being applied as well as in compliance with those therapies. We were impressed with the level of treatment at baseline in our population and concluded that the lack of reduction in healthcare utilization and costs resulted in part from that fact. All of the patients in this study had an established diagnosis of congestive heart failure and almost all had primary care physicians at the time of study entry. This differs from many trials of disease management in which study entry occurred during the initial hospitalization for heart failure in patients who may have had little previous access to health care. It is important to point out, however, that because of the nature of the intervention we tested, a disease management program that provided feedback and recommendations to patients and primary care physicians but did not have independent prescriptive authority, medication doses were not routinely maximized and blood pressure control at the end of the trial was often suboptimal. Thus, there remains further room for improvement in the management of congestive heart failure in our patients, but the disease management program we tested was not successful in bringing it about.
To realize this ultimate goal, requiring the participation of large groups of patients in adjunct programs such as the one we tested will not suffice. The significant challenge remains in developing systems that allow more complete control of patient management in such large groups, so that treatment end points are achieved without interfering with a patient’s relationship with a primary care provider who must manage the patient’s overall health care (often encompassing numerous medical problems) and who must concur with specific therapy recommendations of the disease management program. Only when this goal has been reached will truly optimal disease management be possible.
The Department of Defense funded this study; its interests were in determining whether disease management when applied to federal beneficiaries with congestive heart failure would be effective in reducing mortality, morbidity, and healthcare costs. If significant improvements over usual care were observed, then this or a similar model would have been instituted on a local and perhaps national level in military treatment facilities.