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This study examined patients' perceptions of their providers' participatory decision making (PDM) style and hypertension self-care behaviors and outcomes. Five hundred fifty-four veterans with hypertension enrolled in the Veterans' Study to Improve the Control of Hypertension rated providers' PDM styles using a validated 3-item instrument. Behaviors assessed included presence of a home blood pressure monitor, monitoring frequency, and self-reported antihypertensive medication adherence. Overall, veterans with hypertension rated providers as highly participatory. In adjusted analyses, a lower PDM score was associated with decreased odds of having a home monitor (odds ratio, 0.90 per 10-point decrement in PDM score; 95% confidence interval, 0.83–0.98) but not with monitoring frequency, adherence, or blood pressure control. Providers' involvement of patients in decision making, reflected in ratings of PDM style, may be important to securing patients' participation in their own care, but alone this factor seems insufficient. No relationship between PDM score and blood pressure control was observed.
In the United States, hypertension is the most commonly coded primary diagnosis for an office visit, affecting more than 60 million Americans.1,2 The consequences of uncontrolled hypertension are well documented and include increased risk of myocardial infarction, heart failure, stroke, and kidney disease. Yet, control of high blood pressure is still below 40% nationally, far less than the Healthy People 2010 goal of 50%.3
Participatory decision making (PDM), also known as shared decision making, refers to a patient-centered style of making health care decisions in which providers present patients with the best available evidence; explicitly consider patients' own values, goals, and capabilities; offer options; and negotiate with patients to arrive at mutually agreed-upon treatment plans.4 Having a greater degree of PDM in a patient-provider relationship has been shown to improve health-related outcomes in a number of chronic illnesses, including hypertension.5–10 In one study in which hypertensive patients were asked to rate the level of PDM that occurred at a given visit, higher PDM scores were correlated with lower blood pressures at the next follow-up visit.10
It is not known precisely how PDM style improves chronic illness outcomes.11 Involving patients in their own care may make them more vigilant about their health and potentially improve adherence to medications and other self-care behaviors.12 The goal of this study was to explore the relationship between provider PDM style and patients' actual participation in chronic illness care by identifying possible connections between patients' global PDM ratings of providers and specific patient practices in hypertension.
At the start of an ongoing trial of a multifaceted intervention to improve hypertension outcomes in the US Department of Veterans Affairs (VA) Veterans Health Administration, participants were asked to rate their primary care providers in terms of PDM style. They were also asked about a range of behaviors relevant to hypertension, including whether they had home blood pressure monitors, how frequently they used these monitors, and whether they adhered to prescribed antihypertensive medication regimens. We then tested for associations between participants' PDM ratings and these behaviors, which themselves may be associated with improved blood pressure control.13,14 We also examined whether PDM scores were related to blood pressure control at baseline.
To our knowledge, this study is the first to examine the relationship between provider PDM and hypertension among veterans receiving care in the VA health care system. Veterans represent an important population in the United States for studying the effects of patient-provider relationships because potential confounders related to unequal access to care and lack of coverage for medications and equipment are greatly mitigated.15
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Demographic and clinical characteristics of the study sample are presented in Table I. Mean age ± SD was 63.1±11.2 years; nearly all participants were men. Mean PDM score ± SD was 85.4±20.7. Median PDM score was 96.3; 46% gave their providers the highest score possible. Thirty-four of the 588 original V-STITCH participants (6%) did not answer all 3 PDM questions; the remaining 554 constituted our study sample. Incomplete responders were several years older (mean age ± SD 68.0±13.2 years vs 63.1±11.2 years; P=.02) and had slightly lower REALM scores (52.6±12.1 compared with 57.9±11.3 SD, of a possible 66 total points; P=.02). They were also less likely to have attended college (odds ratio [OR], 2.9; 95% confidence interval [CI], 1.3–6.3; P=.006). Charlson comorbidity scores between the 2 groups were not significantly different (P=.10), however.
Table I. General Characteristics of the V-STITCH Sample
|Mean age, (SD), y||63.1 (11.2)|
|Race, %|| |
|Mean REALM score*||58|
|Some college, %||51|
|12-mo average blood pressure before study, (SD), mm Hg†|| |
| Mean systolic||140.6 (14.7)|
| Mean diastolic||76.9 (9.9)|
|Have home blood pressure monitor, %||60|
|Frequency of home monitoring, %|| |
| Do not have monitor/don't know/no response||50|
|Adherent to antihypertensive medications, %‡||65|
|Baseline blood pressure, (SD), mm Hg §|| |
| Mean systolic||138.0 (17.6)|
| Mean diastolic||75.6 (11.3)|
|Blood pressure “not in control,”%|||55|
|PDM score|| |
| Mean (SD)||85.4 (20.7)|
|V-STITCH indicates the Veterans' Study to Improve the Control of Hypertension; REALM, Rapid Estimate of Adult Literacy in Medicine; and PDM, participatory decision making. *Scored out of 66 total possible points. Nineteen participants (3%) did not complete the REALM measure. †These data were not available for 3 participants (1%). ‡Assessed by validated 4-question self-report instrument.19 Participants were considered nonadherent if they responded “agree” or “strongly agree” to any of the 4 statements. §Twenty participants (4%) did not have blood pressure measured at initial study visit. |As defined by the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure guidelines as <140/90 mm Hg for nondiabetic, <130/85 mm Hg for diabetic patients.|
In unadjusted analyses (Table II), a lower PDM score was significantly associated with decreased odds of having a home blood pressure monitor and an increased likelihood of having controlled blood pressure. PDM score, however, was not associated with frequency of home monitoring (when those without monitors were included as the reference group and when they were excluded entirely) or with self-reported medication adherence.
Table II. Unadjusted Relationship Between PDM and Hypertension Care Outcomes*
|Dependent Variable||OR (95% CI)*||P|
|Having a home blood pressure monitor||0.89 (0.82–0.97)||.006|
|Frequency of home monitoring||0.94 (0.87–1.02)||.14|
|Frequency of home monitoring (those without home monitors excluded)†||0.99 (0.98–1.01)||.28|
|Adherence to medications||1.02 (0.94–1.11)||.61|
|Blood pressure “in control”||1.09 (1.00–1.19)||.04|
|PDM indicates participatory decision making; CI, confidence interval. *Odds ratios (OR) were calculated per 10-unit decrease in PDM score. †Because of the large number of participants who reported not having a home blood pressure monitor, the frequency-of-monitoring question was analyzed in 2 ways: (1) Using patients without monitors as the reference group and (2) excluding those without monitors and using the monthly category as the reference. In the latter case, n=334.|
The results of adjusted analyses largely mirrored those of unadjusted analyses. A lower PDM score was associated with decreased odds of having a home monitor. For each 10-point decrease in PDM score, there was a 9% decrease in the odds of having a home blood pressure monitor (OR, 0.91;95% CI, 0.83–0.99; P=.02) (Table III). Of interest, however, was the fact that after taking other factors into account, a lower PDM score was no longer significantly associated with higher odds of blood pressure control (OR, 1.09; 95% CI, 0.99–1.20; P=.09). Finally, as in the unadjusted analyses, PDM style was not significantly associated with either frequency of home monitor use (OR, 1.02; 95% CI, 0.93–1.12; P=.45) or self-reported adherence to antihypertensive medications (OR, 0.97; 95% CI, 0.89–1.05; P=.64).
Table III. Multivariable Regression Models of PDM and Hypertension Care Outcomes*
|Dependent Variable||n||OverallP Value (Model)||Max-Rescaled R2||C Statistic||OR (95% CI) for PDM†||P Value for PDM|
|Having a home monitor||532||.007||0.07||0.63||0.91 (0.83, 0.99)||.03|
|Frequency of monitoring||532||<.0001||0.07||0.62||0.97 (0.89, 1.05)||.45|
|Medication adherence||532||.11||0.03||0.60||1.02 (0.93, 1.12)||.64|
|Blood pressure control‡||514||<.0001||0.19||0.71||1.09 (0.99, 1.20)||.09|
|CI indicates confidence interval. *Age, race, marital status, Rapid Estimate of Adult Literacy in Medicine (REALM) score, level of education, diabetes status, and 12-month average blood pressure before study entry were included as covariates in all models. Nineteen participants did not complete the REALM measure; 3 did not have blood pressure readings on record before study entry. †Odds ratios (OR) were calculated per 10-unit decrease in participatory decision making (PDM) score. ‡Twenty participants did not have blood pressure measured at baseline clinic visit.|
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Patient self-management, which includes a spectrum of patient-directed self-care activities such as self-monitoring and adherence to medication regimens, is a key component of effective chronic illness care.32 PDM style describes the extent to which patients are encouraged by health care providers to be involved in managing their own health care. One might therefore expect that a more highly participatory provider style would be associated with increased patient self-management, and vice versa. This study, the first to examine PDM and hypertension in veterans, found only limited evidence of such a relationship.
Overall, the veterans in this study rated their providers as highly participatory. Participants who rated their providers lower in terms of PDM also had decreased odds of having blood pressure monitors at home. This finding can be understood as follows: Having a monitor at home is a behavior that is “provider-controlled,” because in the VA, monitors are dispensed via a provider's prescription. Thus, provider characteristics such as PDM are quite influential. On the other hand, the actual frequency of home monitoring and self-reported medication adherence, aspects of hypertension care that are more “patient-controlled,” did not appear to be related to PDM style. These more patient-controlled behaviors clearly depend on the actions of patients themselves, and intuitively one would expect them to be less influenced by provider characteristics.
Studies of other chronic illnesses such as asthma, diabetes, and HIV have found similar trends. PDM style has been associated with certain provider-controlled aspects of care, such as the duration of visits and the provision of asthma action plans, but not with other more patient-controlled activities such as self-monitoring of blood glucose or adherence to antiretroviral therapy.7,9,23 In osteoarthritis, patients with greater PDM scores were slightly less likely to report nonadherence to medications.24
Unlike a prior study of PDM and hypertension,5 our study did not find a relationship between PDM style and the key clinical outcome, blood pressure. Lower PDM scores were actually associated with improved blood pressure control in an unadjusted analysis, but not in the final multivariable model that took into account the baseline severity of participants' hypertension.
One could explain these counterintuitive findings if patients with more refractory disease saw their providers more frequently and developed closer and more participatory relationships with them as a result. Patients whose blood pressure was already well controlled, on the other hand, may have required less interaction with their providers and perceive their relationships with them as being less participatory as a result. There is some observational evidence to suggest that this is the case in ambulatory care settings: one study of family practice providers found that they are most likely to facilitate PDM when seeing patients who have complex medical needs.25 Of course, the possibility of a type II error cannot be overlooked; that is, we did not detect a difference that was actually present due to sample size or other factors.
Key study strengths include the use of a sizable primary care sample. A large proportion of participants were nonwhite and had relatively low incomes, which enhances the generalizability of our findings. In addition, a number of important behaviors and outcomes related to hypertension were evaluated, which gave us the opportunity to gain some insight regarding possible mechanisms for how PDM influences chronic illness care, while being mindful of the limitations discussed below. Finally, potential confounders related to unequal access to care and lack of coverage for medications and home blood pressure monitors were less of an issue in this study because all veterans receiving care in the VAMC have the same basic health insurance coverage.
Limitations of this study include the population studied: US veterans, nearly all men. The sample itself was made up of participants in a study of an intervention to improve hypertension outcomes at the VAMC Durham and may not be representative of hypertensive veterans in general. In addition, many veterans gave their primary care providers the highest PDM rating possible, producing a ceiling effect that has also been observed elsewhere.23 This skewed distribution may have attenuated the relationships between PDM style and outcomes. Explanations could include high satisfaction with care, because PDM ratings have been found to be correlated with satisfaction.26 Plus, in the VAMC, satisfaction with care is significantly higher than in private settings.27,28 Older respondents have also been observed to overuse the upper end of response scales, which would further decrease response variability.29
Other limitations include not having directly observed how participatory the primary care providers rated in this study were in actual practice. The patient-reported instrument used here, however, has been validated and widely used elsewhere.4,6,8,9 More important, it captures patients' own perceptions of their relationships with their providers, which are likely to have a greater influence on patients' behavior than would a third-party assessment of those relationships. We also did not assess patients' preferences for participation, which may interact with PDM to affect health behaviors and outcomes. There is evidence, for example, that the effect of PDM on satisfaction with care is mediated by patient's own participation preferences.26,30 Not all patients want to be active participants.31 Adherence was also not measured directly; we used a validated self-report instrument instead.17