Our study showed that many different interventions—including provider education, provider feedback, provider reminders, patient education, patient reminders, and patient financial incentives—were associated with improvements in provider adherence to guidelines and patient disease control. However, since existing studies do not directly compare different interventions, less is known about which interventions produce the greatest relative improvements in care.
There should be careful consideration of the most effective strategies for changing provider and patient behaviour, since it is difficult to postulate any improvements in patient care if both provider and patient behaviour remains unchanged. Our study showed that many different types of intervention are being used in disease management programmes, with patient education being the commonest. Also, 59% of disease management programmes used two or more interventions, possibly because multiple interventions are thought to be more likely to be successful than single interventions. The wide variety interventions used may reflect the paucity of available information to guide programme development and to define an optimal strategy. It is ironic that disease management programmes are designed to reduce unexplained variations in care, yet there are large and unexplained variations in the design, development, and implementation of disease management programmes.
Because of the promise that disease management holds for improving patient care, about $1bn is invested in disease management programmes in the United States each year.4
The National Committee on Quality Assurance (NCQA) in the United States requires health plans to submit data on two disease management programmes each year for consideration of accreditation. However, this investment in disease management should be guided by information on how to optimise the benefits of these programmes. Unfortunately, disease management programme developers have had limited qualitative or quantitative information about which interventions achieve the greatest benefits, and programmes are therefore highly variable in design.
Strengths and limitations of study
To the best of our knowledge, our study is the first comprehensive attempt to evaluate the effectiveness of different disease management programmes for patients with chronic illness. Our study brought together disparate information of disease management, to allow for qualitative and quantitative interpretation. We evaluated 16
917 different article titles and identified 102 different disease management studies. We evaluated multiple potential implementation strategies for many different diseases and conditions, and we evaluated both the process of care (provider adherence to guidelines) and the outcome of care (disease control). Disease control measures were carefully selected and related to the key clinical goals of the treatment of each disease. In addition, our study provided both qualitative and quantitative information to assess the effectiveness of different interventions; most other studies have evaluated only qualitative findings.4,7,8,10–13
Therefore, in addition to integrated information on the effect sizes of interventions on patient disease control and adherence to guidelines,20
we have provided detailed descriptions of each study (see authors' website www.zynx.com\research\disease_management.htm
Our study has several limitations, most importantly the quality, quantity, and heterogeneity of the original studies. The studies included great variation in interventions used, patient populations, provider populations, and measured processes and outcomes of care. Many provided insufficient detail in the methods section for us to understand the quality of the interventions and the intensity or duration of each intervention. For example, a study might report that provider education was used, but provide insufficient information for readers to understand how the educational process was performed and how to replicate the process.
The clinical significance of effect sizes may be unclear and need to be interpreted with caution and related to the measured clinical effects reported in the trials.20
Few studies directly compared the effectiveness of different interventions, and without direct comparisons of interventions in trials it is difficult to evaluate each intervention's relative effectiveness.
The available published literature shows that most disease management programmes directed at providers and patients are associated with improvements in care. However, little is known about the relative effectiveness and costs associated with different implementation strategies, and few studies have directly compared intervention strategies. Further research is needed to determine the effectiveness and costs of different implementation strategies that could be used in disease management programmes. These studies should adhere to methodological standards and be described in peer reviewed literature in sufficient detail to enable others to understand and reproduce the results in different patient populations, and to understand the relative effectiveness of different disease management interventions for improving the care of patients with chronic diseases.