SEARCH

SEARCH BY CITATION

Abstract

  1. Top of page
  2. Abstract
  3. Methods
  4. Results
  5. Discussion
  6. Limitations and Conclusions
  7. References

Despite improvements in blood pressure (BP) control, a substantial percentage of patients do not achieve target. The relative importance of determinants of poor BP control is unclear. Therefore, the authors conducted a post hoc exploratory analysis to assess determinants of BP control. Data were collected in 45 general practices, which enrolled patients with uncontrolled hypertension. Antihypertensive medication changes throughout the 6-month follow-up period were documented. Baseline and 6-month BPs were recorded. Of the 2030 patients analyzed, 320 had diabetes. Overall, 42% of patients did not achieve BP control. In multivariate analysis, failure to intensify therapy was identified as a significant independent predictor of lesser BP reduction. Of patients unable to reach target after 6 months, only 25% were prescribed ≥3 drugs. Patients with diabetes were significantly less likely to reach target than those without (26% vs 64%, P<.001). Antihypertensive therapy prescribed to patients with diabetes was only marginally more intensive than to those without. In patients with hypertension, whether with or without coexisting diabetes, poor BP control appears to be at least partially due to failure to uptitrate antihypertensive therapy. Clinical inertia is likely an important barrier to BP control. J Clin Hypertens (Greenwich). 2011;13:73–80. © 2010 Wiley Periodicals, Inc.

Significant advances have been made in blood pressure (BP) control. Notwithstanding these improvements, there remains a significant gap between optimal BP control rates, such as those achievable in clinical trials driven by pre-set protocols for antihypertensive drug/dose escalation,1,2 and those achievable in the general community.3

A broad range of factors have been identified that contribute to poor BP control. These include systematic health care delivery factors, financial considerations (both for the patient as well as for the health care system), but probably most importantly, a number of behavioral factors.4–6 Patient-based behavioral factors, mostly reflected by measures of adherence to antihypertensive prescription, remain important predictors of BP control.7,8 However, there has been increasing appreciation of the importance of health care professional–based behavioral factors as determinants of BP control.9–11 Poor BP control linked to health care professional behavior has been most extensively studied in the context of so-called therapeutic (or clinical) inertia.10,12 In general hypertensive populations, the presence of clinical inertia (at the extremes) reduces the probability of BP control by >80%.13

Although patients with hypertension and diabetes are among those at highest risk for hypertension-related complications, they demonstrate the lowest control rates. As demonstrated in a 2006 community-based cross-sectional survey from Ontario, Canada (ON-BP), for the subset of patients with hypertension and diabetes, BP control rates were only approximately half of those without diabetes.14 In the ON-BP survey, only 35% of patients with diabetes and hypertension had BPs below the recommended target of 130/80 mm Hg, as compared with 66% control in the general hypertensive population whose target was 140/90 mm Hg.14 Notably, in those patients with hypertension and diabetes, 59% achieved a BP <140/90 mm Hg—a control rate comparable with that reported for patients without diabetes.14 Whether the disparity between target-specific control rates for those with or without diabetes solely reflects the lower BP targets for those with diabetes (<130/80 mm Hg15,16), resistance to aggressive therapy/use of diuretics by health care professionals and/or a greater prevalence of refractory hypertension in patients with diabetes and hypertension is unclear. Therefore, we conducted a post hoc exploratory analysis to assess possible barriers to BP control, in the context of prescriptions, in the overall patient population as well as in the subset of patients with diabetes who participated in the Simplified Therapeutic Intervention To Control Hypertension (STITCH) study.

Methods

  1. Top of page
  2. Abstract
  3. Methods
  4. Results
  5. Discussion
  6. Limitations and Conclusions
  7. References

STITCH was a cluster randomized controlled trial of hypertension management conducted in southwestern Ontario between February 2005 and January 2007. The study design was previously described in detail.17 Briefly, data were collected in 45 general practices, each enrolling up to 50 patients with uncontrolled hypertension. Eligible patients were men or women, 18 years or older who, on entry to the study, had uncontrolled hypertension (systolic BP [SBP] ≥140 mm Hg or diastolic BP [DBP] ≥90 mm Hg for patients without diabetes mellitus or SBP ≥130 mm Hg or DBP ≥80 mm Hg for patients with diabetes mellitus), and with no history of ischemic heart disease, atrial fibrillation, peripheral vascular disease, stroke, or stage 4 or 5 chronic kidney disease. Patients could not be participating in other hypertension studies. Preintervention and postintervention BP measurements were taken approximately 6 months apart and were based on an average of 5 readings using a standardized procedure and an automated BP device (BpTRU; VSM Med Tech, Coquitlam, British Columbia, Canada). Changes in antihypertensive medication prescription throughout this follow-up period were documented.

In this post hoc analysis, STITCH patients were grouped based on (1) whether they achieved BP control at 6-month follow-up and (2) whether they had a documented diagnosis of diabetes at baseline. Patients whose diabetes status was unknown were excluded from this analysis. Outcomes for this exploratory analysis were BP reduction and the proportion of patients achieving BP target at the 6-month follow-up visit. Antihypertensive medication prescription outcomes explored included the sum of standard daily doses of any antihypertensive medications, sum of standard daily doses of individual classes of medication, number of individual molecules prescribed, and use of fixed-dose combination therapies. Interactions in multivariate regression models were explored to assess whether diabetes status moderated the BP-lowering effects of increasing doses of antihypertensive therapy.

Statistical Methods

Descriptive statistics are presented for baseline characteristics. Two-sample t tests (unadjusted and adjusted for clustering) were used to compare individual-level characteristics of patients with and without diabetes. Estimates of intraclass correlation coefficients were calculated for each outcome variable using methods presented by Donner and Klar (2000) by using the mean square values from a one-way analysis of variance.18,19 We report t tests adjusted by the design effect since the data collected were clustered by family practice in the STITCH study. Two-tailed P values were reported. To adjust for the effects of confounding and clustering by family physician for BP reduction outcomes, the SAS PROC MIXED procedure (restricted maximum likelihood REML method) was used to fit multilevel models that incorporated random effects. Variables with a multivariate P value >.05 were removed from the model.

Since the nature of this study was exploratory, there was no adjustment for multiple testing. All statistical analyses were performed using SAS software, version 9.1 for Windows (SAS Institute Inc, Cary, NC).

Results

  1. Top of page
  2. Abstract
  3. Methods
  4. Results
  5. Discussion
  6. Limitations and Conclusions
  7. References

Of the 2104 hypertensive patients who were analyzed in the STITCH study, 74 were excluded from the analysis, 56 patients withdrew during the study so follow-up data were not available, and 18 patients had incomplete diabetes status data. Thus, this exploratory analysis was based on 2030 patients.

Predictors of Reaching BP Target

Overall, 42% of patients in the STITCH study failed to reach BP targets through the course of the trial (none of whom were at target at baseline). As shown in Table I, patients who did not achieve BP control through the study tended to have higher baseline BPs and demonstrated a much less significant reduction in BP through the course of the study, compared with those who did reach BP target. Notably, the intensity of antihypertensive drug therapy for those patients who failed to reach BP targets was not greater than those who reached targets in terms of the number of drugs prescribed (mean of 1.7 vs 1.9 drugs, respectively), the intensity of drug dosing (mean of 1.7 standard doses regardless of whether target achieved), and the proportion of those taking ≥3 antihypertensive drugs (25% vs 26%, respectively). This finding suggests that even for patients with inadequate BP control, therapy was not advanced to any greater extent than for those who achieved BP control, suggesting a “ceiling” phenomenon for the prescription of >2 antihypertensive drugs.

Table I.   Characteristics of STITCH Patients Based on Achieving Blood Pressure Target at 6-Month Follow-Up
CharacteristicAchieved Target (n=1170)Did Not Achieve Target (n=860)
  1. Abbreviations: DBP, diastolic blood pressure; SBP, systolic blood pressure; SD, standard deviation; STITCH, Simplified Therapeutic Intervention To Control Hypertension.

Blood pressure characteristics
 Baseline SBP, mean (SD), mm Hg152 (13)157 (16)
 SBP change, mean (SD), mm Hg−27 (15)−10 (16)
 Baseline DBP, mean (SD), mm Hg87 (11)89 (11)
 DBP change, mean (SD), mm Hg−13 (9)−4 (11)
Antihypertensive prescription characteristics
 No. of standard doses, mean (SD)1.7 (1.3)1.7 (1.5)
 Increase in standard doses from baseline, mean (SD)0.8 (1.0)0.6 (1.2)
 No. of drugs, mean (SD)1.9 (1.1)1.7 (1.2)
 Increase in No. of drugs from baseline, mean (SD)1.0 (1.0)0.7 (1.1)
 No. of patients taking ≥3 drugs, %302 (26%)214 (25%)
 No. of patients taking ≥2 drugs, %822 (70%)502 (58%)
 No. of patients uptitrated over 6 months, %779 (64%)545 (49%)

Barriers to BP Reduction: Multivariate Analyses

Since BP control for the STITCH population was primarily driven by the extent of SBP control, a multivariate model is presented in Table II with predictors of reduction in SBP. The STITCH-Care treatment algorithm (featuring the use of single-pill combinations), diabetes status and an increase in the number of drugs prescribed prior to the 6-month visit were identified as independent predictors of reduction in SBP after adjustment for baseline SBP.

Table II.   Predictors of Reduction in SBP During 6 Months
DeterminantUnivariate AnalysisMultivariate Model
Δ SBP, mm HgStandard ErrorP ValueaΔ SBP, mm HgStandard ErrorP Valuea
  1. Abbreviations: Δ, change over time; SBP, systolic blood pressure; STITCH, Simplified Therapeutic Intervention To Control Hypertension. aP values were derived by adjustment for clustering in the model. bIncrease based on any antihypertensive therapy prescription change made to baseline medications prior to 6-month follow-up.

STITCH-Care−4.941.60.004−3.021.45.04
Age (per 10-y increase)−1.870.32<.001   
Female−2.520.82.004   
Not diabetic−1.251.11.263−2.260.89.01
Increase in No. of standard dosesb−1.840.38<.001   
Increase in No. of drugsb−3.050.40<.001−2.060.33<.001
Baseline SBP (per 10-mm Hg increase)−6.870.24<.001−6.760.23<.001

BP Control in Patients With Diabetes

Of the 2030 patients analyzed, 320 (16%) had a diagnosis of type I or type II diabetes. Patient-level characteristics are presented in Table III and show that patients in the two groups were relatively similar in terms of demographic and baseline characteristics. However, mean DBP was 4 mm Hg lower in patients with diabetes, likely due to the different definition of control for patients with diabetes in the study entrance criteria. Notably, in this comparison, baseline SBPs were similar in patients with or without diabetes. At baseline, a substantially higher proportion of patients with diabetes had SBP and DBP above target (67%) compared with patients without diabetes (43%), as shown in Figure 1. In essentially all patients with diabetes (99%), SBP was >130 mm Hg, and in the vast majority of those without diabetes (91%) SBP was >140 mm Hg.

Table III.   Baseline Characteristics of STITCH Patients by Diabetes Status
CharacteristicsDiabetesNo Diabetes
  1. Abbreviations: DBP, diastolic blood pressure; SBP, systolic blood pressure; SD, standard deviation, STITCH, Simplified Therapeutic Intervention To Control Hypertension.

No. of patients (%)320 (15.8)1710 (84.2)
Age, mean (range), y61.84 (20.8–88.7)61.2 (18.6–93.0)
Women, %50.054.6
Baseline SBP, mean (SD), mm Hg155.5 (14.5)154.0 (14.3)
Baseline DBP, mean (SD), mm Hg84.5 (10.8)88.6 (10.8)
Randomized to STITCH-Care arm, %37.539.7
image

Figure 1.  Breakdown of uncontrolled blood pressure based on systolic blood pressure (SBP), diastolic blood pressure (DBP), or both uncontrolled at baseline, by diabetes status.

Download figure to PowerPoint

BP outcomes after 6 months of follow-up are reported in Table IV by diabetes status. At 6 months, patients with diabetes were significantly less likely to reach their recommended BP target than those without diabetes (26% vs 64%, P-adjusted <.001). Notably, the mean BP reduction during the 6-month follow-up was comparable between patients with diabetes (change in SBP [ΔSBP], 18.7±18.2 mm Hg; change in DBP [ΔDBP], 8.2±11.9 mm Hg) and patients without diabetes (ΔSPB, 19.9±18.0 mm Hg; ΔDBP, 9.2±10.5 mm Hg) as was the proportion of patients who reached a common target of 140/90 mm Hg (diabetes, 60.6%; no diabetes, 63.6%; P-adjusted=.692).

Table IV.   Blood Pressure Outcomes at 6-Month Follow-Up
OutcomeDiabetes (n=320)No Diabetes (n=1710)P ValueICCAdjusted P Valuea
  1. Abbreviations: CI, confidence interval; DBP, diastolic blood pressure; ICC, intraclass correlation coefficient; SBP, systolic blood pressure. aAdjusted for clustering.

Blood pressure at target, %25.963.6<.0010.101<.001
Blood pressure at target 140/90 mm Hg, %60.663.6.3170.122.692
SBP reduction, mean (95% CI), mm Hg18.7 (16.7–20.7)19.9 (19.0–20.7).2840.082.618
DBP reduction, mean (95% CI), mm Hg8.2 (6.9–9.5)9.2 (8.7–9.7).1560.083.511

Prescription-Based Barriers to Poor BP Control in Patients With Diabetes

Antihypertensive drug therapy prescriptions are summarized by diabetes status in Table V. Based on clinical trial findings,4 we would have expected that patients with diabetes receive 1 or 2 drugs more than those without diabetes in order to achieve comparable BP control rates. However, despite being much less likely to achieve BP targets, patients with diabetes were only taking a slightly higher number of drugs (mean number of drugs: diabetes, 2.26; 95% confidence interval [CI], 2.12–2.39; no diabetes, 1.86; 95% CI, 1.82–1.92; P-adjusted <.048), and only marginally more intensive antihypertensive therapy, measured as standard daily doses (mean standard doses: diabetes, 2.35; 95% CI, 2.17–2.54; no diabetes, 1.65; 95% CI, 1.59–1.71; P-adjusted <.001). Interestingly, the apparent resistance to advancing antihypertensive therapy in patients with diabetes (despite not achieving BP targets) was not due to resistance to the use of diuretics. In fact, there was a trend toward patients with diabetes being prescribed slightly more intensive diuretic therapy (mean standard doses of diuretic if prescribed: diabetes, 0.87; 95% CI, 0.78–0.97; no diabetes, 0.74; 95% CI, 0.71–0.78; P-adjusted=.12). Although patients with diabetes were as likely to be prescribed a diuretic as those without diabetes, in both subgroups, patients who achieved target were more likely to be prescribed a diuretic than those who did not achieve target (diabetes, 75.9% vs 61.6%, P=.02; no diabetes, 69.9% vs 61.3%, P<.001). As would be expected, patients with diabetes were more likely to be prescribed an angiotensin-converting enzyme [ACE] inhibitor than patients without diabetes (55% vs 35%). The proportion of patients using any fixed-dose combination therapy (all of which contained a diuretic) at the follow-up visit was not significantly different between the two groups.

Table V.   Antihypertensive Medication Use at 6-Month Follow-Up
Medication UseDiabetes (n=320)No Diabetes (n=1710)P ValueICCAdjusted P Valuea
  1. Abbreviations: ACE, angiotensin-converting enzyme; ARB, angiotensin receptor blocker; BB, β-blocker; BP, blood pressure; CCB, calcium channel blocker; CI, confidence interval; ICC, intraclass correlation coefficient. aAdjusted for clustering. bDrug intensity measured as mean standard doses. cMean of all patients including those with dose of 0.

All antihypertensive drugs
 No. of drugs, mean (95% CI)2.26 (2.12–2.39)1.86 (1.82–1.92)<.0010.150.048
 Drug intensity, mean standard doses (95% CI)2.35 (2.17–2.54)1.65 (1.59–1.71)<.0010.071<.001
Patients using specific drug classes, No. (%)
 Diuretic209 (65)1141 (67)   
 ACE inhibitor176 (55)589 (34)   
 ARB116 (36)646 (38)   
 CCB131 (41)463 (27)   
 BB70 (22)271 (16)   
Drug intensityb by individual class, overall, mean (95% CI)c
 Diuretic0.57 (0.49–0.65)0.50 (0.47–0.52).080.058.35
 ACE inhibitor0.83 (0.72–0.94)0.42 (0.39–0.46)<.0010.087.002
 ARB0.39 (0.33–0.46)0.40 (0.37–0.42).930.192.93
 CCB0.36 (0.30–0.41)0.22 (0.20–0.24)<.0010.053.01
 BB0.18 (0.13–0.23)0.10 (0.09–0.11).0050.028.06
Drug intensityb by individual class, if prescribed, mean (95% CI)
 Diuretic0.87 (0.78–0.97)0.74 (0.71–0.78).010.058.12
 ACE inhibitor1.51 (1.37–1.65)1.22 (1.16–1.29)<.0010.087.02
 ARB1.09 (0.99–1.18)1.05 (1.01–1.09).480.192.73
 CCB0.87 (0.79–0.95)0.81 (0.76–0.85).160.053.27
 BB0.81 (0.64–0.97)0.64 (0.59–0.68).0490.028.07

As seen in Figure 2, patients who achieved their BP target at 6 months were significantly more likely to be taking 2+ therapies than those who did not reach target (diabetes, 81% vs 68%, P=.03; no diabetes, 70% vs 55%, P<.001).

image

Figure 2.  Proportion of patients taking 0 (□), 1 (inline image), 2 (inline image), or 3+ (inline image) antihypertensive medications by diabetes status and achieving blood pressure target at 6-month follow-up.

Download figure to PowerPoint

Discussion

  1. Top of page
  2. Abstract
  3. Methods
  4. Results
  5. Discussion
  6. Limitations and Conclusions
  7. References

Overall, the STITCH trial demonstrated that introduction to health care practitioners of a simplified treatment algorithm for the management of hypertension improved BP control. Notwithstanding, the BP control rates achieved through the course of the STITCH study were similar to those seen in a community setting. These control rates fall far short of those seen in large clinical trials where patients were treated according to a fixed treatment protocol (and where compliance to adherence to the protocol was closely monitored). The data collected from the STITCH trial offered an opportunity to explore the drug-related determinants of poor BP control. This analysis demonstrated that patients who did not achieve target BPs were not prescribed more antihypertensive therapy. This analysis also confirmed the observation that patients with diabetes have significantly lower BP control rates. Despite their poor BP control rates, patients with diabetes were prescribed only marginally greater intensity of antihypertensive therapy. Lastly, our analysis demonstrated that this resistance to more aggressive treatment in patients with diabetes was not due to an obvious aversion to the use of diuretics.

Overall, the BP control rates achieved in the STITCH trial would appear to be representative of those seen in a general population of patients with hypertension, considering that only patients with uncontrolled hypertension at entry could participate in the STITCH study. The 6-month control rate of 58% among the population of STITCH patients (presumably) aware of their diagnosis is less than the control rates among “aware patients” reported in several recent North American population-based surveys (eg, 62% in National Health and Nutrition Examination Survey [NHANES] 20083 and 76% in ON-BP14). On the other hand, the STITCH population would have included proportionally more patients with newly diagnosed/uncontrolled hypertension and/or more refractory hypertension, considerations that would be expected to result in a somewhat lower control rate than that seen in a general population of patients with hypertension. Notably, these control rates were almost identical to those reported during a comparable follow-up period for Canadian sites in the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) (55% at 6 months20).

In the general population of patients studied in the STITCH trial, those who failed to reach target BPs started with higher baseline pressures and demonstrated a lesser response to antihypertensive therapy. Multiple factors contribute to resistance to antihypertensive therapy, including noncompliance and secondary forms of hypertension. Since the assessment of antihypertensive drug intensity was based on physician records and not by prescription refills, persistence to therapy and compliance could not be determined from the STITCH trial data. Further, the prevalence of a number of secondary forms of hypertension was not systematically assessed. However, regardless of the etiology of the resistance to therapy, it is most notable that the response to poor BP control in these patients did not include any significant increase in their antihypertensive drug prescription. For the majority of these patients, a prescription ceiling was reached at 2 antihypertensive medications with resistance to escalating therapy beyond that ceiling despite failure to achieve BP target. Thus, regardless of the presence or absence of any other biologic or patient behavioral characteristics leading to poor BP control, therapeutic inertia is seen as a key factor. Notably, at the time of the study, only 2-drug single-pill combinations were available in Canada. With the re-emergence of 3-drug single-pill combinations in the near future and the clear evidence of the utility of single-pill combinations to ameliorate therapeutic inertia, we would speculate that the greater availability of these formulations may raise the ceiling in antihypertensive prescription resistance.

Patients with hypertension and diabetes are much less likely to reach BP targets. Notwithstanding their lack of BP control, patients with diabetes were receiving only slightly more intensive antihypertensive drug therapy than those without diabetes. Surprisingly, patients with diabetes were equally likely to be treated with a diuretic and were taking a marginally higher dose of diuretic, suggesting that the long-standing concern over diuretic-induced insulin resistance21 has not outweighed the appreciation of the BP-lowering benefits of the drug in the opinion of many primary physician prescribers. In the ON-BP study, McInnis and colleagues reported significantly lower use of diuretics among patients with diabetes.22 They suggested that the aversion to the use of diuretics might constitute a significant factor in their lower BP control rates. In the STITCH study, the use of diuretics was not reduced in patients with diabetes. The reason for this discrepancy is unclear but could relate to the emphasis on the use of single-pill combinations, which, at the time of the study, universally included thiazide diuretics. However, regardless of the explanation for this discrepancy, our data support the hypothesis that even in the setting where diuretic use is not a limiting factor, BP control rates in patients with diabetes remain significantly lower than in those without diabetes, and drug prescription intensity remains suboptimal. Thus, aversion to diuretic use cannot be viewed as the only factor responsible for suboptimal management of hypertension in this high-risk population.

Increased biologic resistance to antihypertensive treatment for patients with diabetes has been suggested as an important component of the challenge in managing BP for this subpopulation. Interestingly, when modified BP targets were explored, patients without diabetes displayed parallel losses in control rate as BP target was lowered compared with patients with diabetes. Thus, our data do not suggest that lower BP targets are differentially more difficult to achieve for patients with diabetes, but rather that failure to achieve lower treatment targets was primarily behavioral and included failure to intensify therapy. It has been speculated that part of the difficulty in achieving better BP control rates in patients with diabetes was related to a lack of “buy-in” by health care professionals about the merits of more aggressive treatment targets (ie, <130/80 mm Hg) for patients with diabetes. Whether the recent findings from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study, ie, failing to show benefit of adopting an SBP target <140 mm Hg in regards to reduction in major cardiovascular events,23 will further erode the extent of buy-in to the benefit of lower targets remains to be determined.

Our data support the hypothesis that resistance to advancing antihypertensive therapy past a “ceiling” of 2 antihypertensive drugs remains a significant barrier to better BP control in patients with diabetes. In patients without diabetes, studies such as ALLHAT have reported that, on average, 2 or 3 antihypertensive drugs are required to achieve the >75% BP control rates,20,24 characteristic of large, regimented clinical trials using a 140/90 mm Hg target. In contrast, to achieve lower BP targets, such as in patients with additional cardiovascular risk factors such as diabetes, or to control patients with refractory hypertension, ≥3 antihypertensive agents are generally required.4 In the STITCH study, after 6 months of follow-up, patients with diabetes were receiving, on average, only slightly more than 2 antihypertensive drugs. Notwithstanding, differences in length of follow-up (the ALLHAT study’s BP control rates were reported for up to 5 years of follow-up), in our comparison of those prescribing factors differentiating patients who did or did not achieve BP targets, we would suggest that resistance to the prescription of the third (and potentially fourth) drug required to control BP in patients with diabetes appears to be a major barrier to adequate BP control.

Potential causes of resistance to escalation of antihypertensive therapy in patients with diabetes that could not be explored in our data include: (1) health care professional resistance to escalation of dosing/addition of additional antihypertensive drugs, and (2) increasing patient resistance to being prescribed additional antihypertensive drugs. However, we have observed that in hypertensive patients with diabetes, similar to in the larger population of hypertensive patients without diabetes, insufficient uptitration (clinical inertia) appears to be associated with poor BP control.

Limitations and Conclusions

  1. Top of page
  2. Abstract
  3. Methods
  4. Results
  5. Discussion
  6. Limitations and Conclusions
  7. References

Several limitations to this study should be noted. First, since this was a post hoc analysis and intended to be exploratory, confirmatory studies would be required to support any conclusion. There was no adjustment made for multiple testing. Second, diagnosis of diabetes was only captured at baseline. There may have been patients diagnosed with diabetes within the 6 months of study follow-up who were classified as not having diabetes. Finally, antihypertensive medication data were based on reported prescriptions rather than pharmacy fill records or patient-reported compliance. This method may result in a higher estimate of antihypertensive medication use. However, it should accurately reflect physician willingness to intensify treatment.

Notwithstanding these limitations, this post hoc analysis suggests that poor BP control is associated with clinical inertia or failure to uptitrate antihypertensive therapy in patients both with and without diabetes. In both subgroups, the increased number of drugs required for control to target could be an important limiting factor impeding improved BP control rates. Remedies to clinical inertia in primary care may include a focus on the patient’s role in therapy intensification, improved BP monitoring, effective research dissemination to physicians regarding appropriate aggressiveness of antihypertensive treatment, and potentially the use of 3-drug single-pill combination therapies.

Disclosures:  Dr Feldman and Sigrid Nelson had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. The sponsor had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript. The STITCH study was supported by an unrestricted grant-in-aid from Pfizer Canada, Kirkland, Quebec.

References

  1. Top of page
  2. Abstract
  3. Methods
  4. Results
  5. Discussion
  6. Limitations and Conclusions
  7. References
  • 1
    ALLHAT Officers and Coordinators for the ALLHAT Collaborative Research Group. Major outcomes in high-risk hypertensive patients randomized to angiotensin-converting enzyme inhibitor or calcium channel blocker vs diuretic: the antihypertensive and lipid-lowering treatment to prevent heart attack trial (ALLHAT). JAMA. 2002; 288(23):29812997.
  • 2
    Julius S, Kjeldsen SE, Weber M, et al. Outcomes in hypertensive patients at high cardiovascular risk treated with regimens based on valsartan or amlodipine: the VALUE randomised trial. Lancet. 2004;363(9426):20222031.
  • 3
    Egan BM, Zhao Y, Axon RN. US trends in prevalence, awareness, treatment, and control of hypertension, 1988–2008. JAMA. 2010;303(20):20432050.
  • 4
    Chobanian AV, Bakris GL, Black HR, et al. The seventh report of the Joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure: the JNC 7 report. JAMA. 2003;289(19):25602572.
  • 5
    Ogedegbe G. Barriers to optimal hypertension control. J Clin Hypertens (Greenwich). 2008;10(8):644646.
  • 6
    Schmittdiel JA, Uratsu CS, Karter AJ, et al. Why don’t diabetes patients achieve recommended risk factor targets? Poor adherence versus lack of treatment intensification. J Gen Intern Med. 2008;23(5):588594.
  • 7
    Bramley TJ, Gerbino PP, Nightengale BS, et al. Relationship of blood pressure control to adherence with antihypertensive monotherapy in 13 managed care organizations. J Manag Care Pharm. 2006;12(3):239245.
  • 8
    Elliott WJ. What factors contribute to the inadequate control of elevated blood pressure? J Clin Hypertens (Greenwich). 2008;10(suppl 1):2026.
  • 9
    Moser M. Physician or clinical inertia: what is it? Is it really a problem? And what can be done about it? J Clin Hypertens (Greenwich). 2009;11(1):14.
  • 10
    Oliveria SA, Lapuerta P, McCarthy BD, et al. Physician-related barriers to the effective management of uncontrolled hypertension. Arch Intern Med. 2002;162(4):413420.
  • 11
    Ho PM, Magid DJ, Shetterly SM, et al. Importance of therapy intensification and medication nonadherence for blood pressure control in patients with coronary disease. Arch Intern Med. 2008;168(3):271276.
  • 12
    Phillips LS, Branch WT, Cook CB, et al. Clinical inertia. Ann Intern Med. 2001;135(9):825834.
  • 13
    Okonofua EC, Simpson KN, Jesri A, et al. Therapeutic inertia is an impediment to achieving the Healthy People 2010 blood pressure control goals. Hypertension. 2006;47(3):345351.
  • 14
    Leenen FH, Dumais J, McInnis NH, et al. Results of the Ontario survey on the prevalence and control of hypertension. CMAJ. 2008;178(11):14411449.
  • 15
    American Diabetes Association. Standards of medical care in diabetes--2009. Diabetes Care. 2009;32(suppl 1):S13S61.
  • 16
    Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. Canadian Diabetes Association 2008 clinical practice guidelines for the prevention and management of diabetes in Canada. Can J Diabetes. 2008;32(suppl 1):S1S201.
  • 17
    Feldman RD, Zou GY, Vandervoort MK, et al. A simplified approach to the treatment of uncomplicated hypertension: a cluster randomized, controlled trial. Hypertension. 2009;53(4):646653.
  • 18
    Donner A, Klar N. Design and Analysis of Cluster Randomization Trials in Health Research. London, England: Arnold; 2000.
  • 19
    Donner A, Koval JJ Design considerations in the estimation of intraclass correlation. Ann Hum Genet. 1982; 46(Pt 3):271277.
  • 20
    Cushman WC, Ford CE, Cutler JA, et al. Success and predictors of blood pressure control in diverse North American settings: the Antihypertensive and Lipid-Lowering Treatment to prevent Heart Attack Trial (ALLHAT). J Clin Hypertens (Greenwich). 2002;4(6):393404.
  • 21
    Dronavalli S, Bakris GL. Mechanistic insights into diuretic-induced insulin resistance. Hypertension. 2008;52(6): 10091011.
  • 22
    McInnis NH, Fodor G, Lum-Kwong MM, et al. Antihypertensive medication use and blood pressure control: a community-based cross-sectional survey (ON-BP). Am J Hypertens. 2008;21(11):12101215.
  • 23
    The ACCORD Study Group. Effects of intensive blood-pressure control in type 2 diabetes mellitus. N Engl J Med. 2010;362(17):15751585.
  • 24
    Bakris GL. A practical approach to achieving recommended blood pressure goals in diabetic patients. Arch Intern Med. 2001;161(22):26612667.