Background
Diabetes affects 21 million Americans at an annual cost of over 130 billion dollars. Despite improvements in quality of diabetes care over the last decade, considerable room for improvement remains [
1]. The Institute of Medicine has called for "patient-centered" approaches to care, particularly for patients with major chronic conditions such as diabetes [
2]. A key question is how primary care physicians can achieve patient-centered care in ways that improved clinical outcomes. In this paper, we assessed two approaches to this end: "communicative support" and "practical support".
Physicians can empower patients by providing choices, being responsive to patient preferences, and understanding, listening, and encouraging patients to ask questions. An approach that affirms the patient's capacity to identify and learn to solve their own problems relies on a patient-centered consultation style and effective communication between doctor and patient [
3]. In the last decade, many primary care physicians have been trained to employ these techniques in patient care. However, evidence across studies is inconsistent regarding whether doctor-patient communication that promotes patient autonomy and self-management can, by itself, improve clinical outcomes [
4,
5].
A complementary view is that improving clinical outcomes depends on practical support from health care teams that facilitate patients' self-management through tangible actions such as: issuing a written care plan agreed on with the patient; setting treatment goals; and providing proactive follow-up to monitor disease control and treatment adherence [
6]. The Chronic Care Model advocates "productive interaction" of an "activated patient" with a "proactive clinic team" as a means of improving the clinical outcomes of patients with diabetes and other chronic diseases, placing at least as much emphasis on practical support as on communication [
7]. DiMatteo, in a review of interventions to enhance medication adherence, concluded that practical support had greater effects than emotional support [
8]. Others have concluded that behavioral interventions focusing directly on patients' behavior are more effective at improving clinical outcomes in diabetes care than changing how physicians communicate with patients [
9].
Reviews of controlled trials of diabetes care have concluded that practical support has beneficial effects on clinical outcomes [
10]. However, it is unclear how much the type and level of support that primary care teams currently offer affects diabetes clinical outcomes under community practice conditions. In a recent paper in
JAMA, Pogach et al. observed that: "Although efficacy trials are sufficient for guideline recommendations [...] effectiveness studies, technical considerations (bias, variability in practice and definition of population at risk) [...] are also pertinent" to assess the impact of physician performance on population health among patients with diabetes [
11].
This prospective, observational evaluation of the influence of primary care physician support on diabetes outcomes addresses these issues. Specifically, this paper assesses, under community practice conditions, the extent to which two forms of support for patients with diabetes influence glycemic control outcomes. We compare physicians whose patients rate them more (or less) favorably on: a) practical support for diabetes care (e.g., proactive follow-up, setting agreed-on goals, and developing a written action plan); and b) communicative support (e.g., empathic listening and encouraging patients to ask questions). We prospectively assessed the effects of physician support, as evaluated by patients, on glycemic control.
Results
The questionnaire was sent to 9063 patients from the Group Health registry between March 2001 and August 2002, of whom 7841 were eligible for the study. Questionnaires were returned by 4839 (61.7%). We included 3897 patients from 106 physicians. The number of patients per physician ranged from 5 to 105 with a mean of 40.3 patients (
SD 24.1) per physician. We excluded patients who: did not give their consent to a review of automated medical records (n = 369); did not have two HbA1c tests available at least six months apart (
n = 365); did not have valid data for the Health Care Climate Questionnaire (
n = 165); did not report their educational level (
n = 39); and/or whose primary care physician had fewer than five patients with diabetes included in the study (
n = 4 patients). Almost half were older than 65 years (47.8%), 20.1% were non-Caucasian, about two thirds had not graduated from college, and 95.6% had a type II diabetes. At baseline, 73.1% had an HbA1c >7%, and 24.1% had no oral hypoglycemic or insulin treatment (Table
2).
Table 2
Baseline characteristics of patients (N = 3897)
Age (years)
| |
<65 | 52.1 |
Sex
| |
Female | 48.3 |
Race
| |
White/Caucasian | 79.9 |
Black/African American | 8.2 |
Asian or Pacific Islander | 9.0 |
American Indian/Alaskan Native | 1.5 |
Other | 1.4 |
Education
| |
<College graduate | 64.6 |
≥College graduate | 35.3 |
Marital Status
| |
Unmarried | 33.0 |
Married | 66.9 |
Employment
| |
No | 56.7 |
Yes | 43.2 |
HbA
1c
baseline
| |
<7.0% "optimal" control | 26.8 |
>9.0% "poor" control | 25.1 |
Treatment intensity
| |
No treatment | 24.1 |
Oral hypoglycemic only | 46.2 |
Insulin or/and oral hypoglycemic | 29.6 |
The mean time interval between baseline and follow-up HbA1c measurement was 23.1 (SD 4.4) months, with minimum and maximum intervals of 7.4 and 55 months, respectively. The mean HbA1c value was 8.1% at baseline and 7.5% at follow-up, reflecting concurrent national trends toward improvement in glycemic control [
1].
The prospective analysis of predictors of HbA1c at follow-up found that being seen by a physician with a higher mean level of practical support was associated with more favorable glycemic control outcomes. Baseline HbA1c, the other indicators of diabetes severity, and the time interval between baseline and follow-up HbA1c measures were also significant predictors of follow-up HbA1c (Table
3). After controlling for the case-mix variables, the physician's mean level of practical support was a significant predictor of follow-up HbA1c (
p = .040). The patient-level deviation from the physician's mean level of practical support was not associated with differences in HbA1c outcomes. In contrast, neither the physician's mean level of communicative support, nor the patient deviation from the physician's mean, was associated with differences in HbA1c outcomes.
Table 3
Linear regression model (GEE) for weighted associations with follow-up HbA1c
Years with diabetes | 0.0123 | 0.0066 - 0.0179 | <.0001 |
Insulin use | 0.2004 | 0.0717 - 0.3291 | <.0001 |
Months between HbA1c measures | 0.0463 | 0.02307 - 0.0619 | <.0001 |
Baseline HbA1c
| 0.3857 | 0.3524 - 0.4246 | <.0001 |
Baseline PHQ-9 | 0.0077 | -0.0008 - 0.0161 | .0753 |
Practical support (physician mean) | -0.1787 | -0.3494 - -0.0081 | .0401 |
Practical support (individual patient as deviation from physician mean) | 0.0196 | -0.0158 - 0.0550 | .2779 |
Communicative support (physician mean) | 0.1053 | -0.0689 - 0.2796 | .3361 |
Communicative support (individual patient as deviation from physician mean) | 0.0067 | -0.0381 - 0.0514 | .7702 |
Table
4 shows the proportion of patients with "poor" and "optimal" HbA1c by the average level of practical support and communicative support that the clinic team provided at baseline and at follow-up. The top data compares the percentage of patients with "optimal" control (HbA1c <7%). At baseline, differences were not significant, whereas at follow up the percentage with "optimal" control differed significantly across the three levels of practical support. Likewise, the percentage with "poor" control (HbA1c >9%) was somewhat (but not significantly) lower in the low-support group at baseline, but the percentage with "poor" control differed significantly at follow-up across the three levels of practical support (at the bottom). It is important to note that the differences in trends in the percentage with "optimal" and "poor" glycemic control were modest across the three levels of communicative and practical support. However, the observed differences in glycemic control trends emerged over a follow-up period averaging 23 months.
Table 4
Proportion of patients with unadjusted HbA1c by average level of communicative and practical support that clinic team provided at baseline and at follow-up (mean, 24 months).
Baseline
N = 1045
| 28.7% | 26.3% | 26.1% |
n.s.
| 23.8% | 27.7% | 26.4% |
n.s.
|
Follow-up
N = 1518
| 40.6% | 39.0% | 35.5% |
n.s.
| 34.5% | 39.6% | 40.9% |
.022
|
Poor glycemic control (HbA
1c
>9%)
|
|
Communicative support
| |
Practical support
| |
|
Low
|
Medium
|
High
|
P
|
Low
|
Medium
|
High
|
P
|
Baseline
N = 1042
| 24.0% | 26.9% | 30.1% |
n.s.
| 28.6% | 26.6% | 24.9% |
n.s.
|
Follow-up
N = 583
| 14.2% | 14.7% | 17.4% |
n.s.
| 17.6% | 14.8% | 12.6% |
.028
|
Discussion
In response to a call for community-based research on how clinical care influences diabetes outcomes [
11], this paper employed an observational, prospective design to assess implications of differences in practical support and communicative support from primary care physicians on glycemic control outcomes among patients with diabetes. The key result of this study was that physicians' characteristic level of practical support (as rated by their patients) was associated with more favorable glycemic control outcomes after controlling for baseline HbA1c and other measures of diabetes severity. Contrary to expectation, physicians' level of communicative support was not associated with differences in glycemic control outcomes, although practical and communicative support were correlated.
Since this study was observational, these results need to be considered in light of relevant experimental studies. The results of this observational study are generally consistent with findings from prior experimental and observational studies concerning effects of clinic team support for diabetes self-management. A growing body of experimental research has shown beneficial effects on clinical outcomes of interventions that enhance the organization of diabetes care in ways that afford practical support for patient self-management [
10]. This observational research extends the experimental results by suggesting that differences in practical support observed in community practice settings may influence long-term trends in glycemic control. In contrast, interventions that have targeted the doctor-patient communication style in diabetes care have not consistently shown effects on patient outcomes. In controlled studies, physician training improved physicians' communication skills and patients' well-being and satisfaction - but not patients' HbA1c levels [
21].
Schillinger trained physicians in communications skills and found positive effects on HbA1c (<8.6%) for patients with low health literacy [
22]. These inconsistent results concerning benefits of enhanced doctor-patient communication have also been reported for other chronic conditions. While experimental studies with direct observation of doctor-patient communication have shown that it is possible to improve the quality of communication, evidence is limited that such changes improve clinical outcomes [
23]. A recent review reported improved clinical outcome in only two of seven provider-targeted interventions to improve patient participation [
24]. In Griffin's review, almost half of the 11 studies focused on provider communication skills training programs found at least one worsened outcome in the intervention group [
4]. The contribution of this paper is to suggest that differences in practical support observed across physicians in community practice settings may influence glycemic control among persons with diabetes.
In ambulatory diabetes care in community practice, the primary task is to minimize the incidence of "poor" glycemic control, while maximizing the prevalence of "optimal" control is a secondary goal [
11]. Our findings suggest that differences in levels of practical support offered by community-based health care teams may influence glycemic control outcomes over an observation period of about 2 years. In contrast, individual patient differences in practical support levels, from their physician's mean level of practical support, did not predict differences in glycemic control outcomes. Features of practical support - such as proactive follow-up, setting agreed-on goals, and developing a written action plan - require organization of the primary care team. Therefore, a physician's typical level of practical support may reflect important differences not only in physician care, but in how well care is organized by the entire clinic team - including other team members than the physician [
25]. It is also possible that using information from multiple patients yielded more reliable and valid measurement of practical support provided by health care teams. It is interesting that in our analysis communicative support for diabetes care alone was not associated with differences in glycemic control outcomes. Patient ratings of communicative support were correlated with their ratings of practical support, so these two forms of support are interrelated. Communicative support may be necessary, but insufficient by itself to affect patient outcomes. On the other hand, practical support may complement doctor-patient communication. The findings of this observational study suggest that an organized approach to providing practical support for self-management influenced long-term trends in glycemic control. The benefits of practical support may be augmented by effective doctor-patient communication and a relationship that empowers patients in managing their disease [
26,
27].
Limitations of this study need to be considered in interpreting the results. Provider support was determined by ratings of multiple patients rather than by direct observation. Patients' global ratings of health care quality have been shown to be unrelated to objective overall measures of technical quality of care [
28]. However, we measured patients' perceptions of specific behaviorally defined aspects of patient care that have been found useful in prior research, particularly when results are aggregated across larger numbers of patients [
29]. Due to constraints on questionnaire length, an abbreviated questionnaire was used to assess physicians' practical and communicative support. Ideally, the effects of practical and communicative support would be assessed through experimental manipulation and direct observation of support, but such a study would be expensive and difficult. This observational study sheds light on the implications of differences in support levels observed in community practice rather than support levels achieved under experimental conditions. In contrast to prior observational studies assessing effects of provider support on diabetes outcomes, we adjusted for important confounders, specifically baseline HbA1c and clinical factors associated with HbA1c. Since poor glycemic control may influence the care received by patients with diabetes (more or less attention and support), the use of a prospective design controlling for baseline HbA1c is an important feature of this study. However, it is, of course, possible that other unmeasured confounders may explain differences in glycemic control outcomes between patients managed by physicians rated as providing high versus low levels of practical support.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
JG: Conception and design, analysis and interpretation, statistical analysis, drafting of the article, critical revision of the article for important intellectual content, final approval of the article, obtaining funding. MvK: Conception and design, data collection, analysis and interpretation, statistical analysis, drafting of the article, critical revision of the article for important intellectual content, final approval of the article, obtaining funding. CMR: Conception and design, data collection, analysis and interpretation, statistical analysis, drafting of the article, critical revision of the article for important intellectual content, final approval of the article, obtaining funding. MDS: Conception and design, analysis and interpretation, statistical analysis, drafting of the article, critical revision of the article for important intellectual content, final approval of the article, obtaining funding. EJL: Data collection, analysis and interpretation, critical revision of the article for important intellectual content, final approval of the article. EHBL: Data collection, analysis and interpretation, critical revision of the article for important intellectual content, final approval of the article. PC: Data collection, analysis and interpretation, critical revision of the article for important intellectual content, final approval of the article. BAY: Data collection, analysis and interpretation, critical revision of the article for important intellectual content, final approval of the article. EHW: Analysis and interpretation, critical revision of the article for important intellectual content, final approval of the article. WJK: Conception and design, data collection, analysis and interpretation, critical revision of the article for important intellectual content, final approval of the article, obtaining funding.