The Need for Improved Medical Management of Patients With Concomitant Hypertension and Type 2 Diabetes Mellitus

Published Online: April 01, 2005
Paul J. Godley, PharmD; Susan K. Maue, PhD; Eileen W. Farrelly, MPH; and Feride Frech, MPH, RPh

Objectives: To determine level of blood pressure (BP) control and to evaluate hypertension management strategies in patients with hypertension and type 2 diabetes mellitus.

Study Design: Retrospective review of 2 consecutive years of pharmacy and medical insurance claims data and medical charts from patients participating in 10 health plans in 9 states.

Patients and Methods: Patients 18 years and older with a medical or pharmacy claim related to hypertension were identified and assessed for inclusion in the database. A random sample of medical charts was reviewed to confirm the diagnoses of hypertension and diabetes mellitus and degree of BP control and to assess the prevalence of other cardiovascular disease risk factors and current antihypertensive treatment.

Results: Type 2 diabetes mellitus was documented in 977 patients. The mean age was 64.3 years, and 55.1% were women. A BP goal of less than 130/85 mm Hg was achieved in 192 patients (19.7%), and a BP goal of less than 130/80 mm Hg was achieved in 135 patients (13.8%). Fifty-two percent of patients had dyslipidemia, and 87.6% were overweight, obese, or morbidly obese; tobacco use was documented in 19.5%.

Conclusions: Hypertensive diabetic patients are frequently not treated to their goal BP, which requires the use of 2 or more agents in most patients. Quality improvement programs should emphasize the importance of treating hypertensive diabetic patients to their goal BP, as well as controlling other major cardiovascular disease risk factors, such as smoking, dyslipidemia, and overweight or obesity, that are prevalent among these high-risk patients.

(Am J Manag Care. 2005;11:206-210)

Arecent survey released by the American Diabetes Association reports that cardiovascular disease is a major unrecognized problem in patients with type 2 diabetes mellitus in the United States.1 While heart disease and stroke are the leading causes of death among people with diabetes mellitus, 68% of diabetic patients are not aware of the significant risk posed by cardiovascular disease. Fortunately, more than 90% of physicians surveyed are aware of the link between diabetes mellitus and cardiovascular disease, although there is recognition of the need to become more aggressive in treating not only blood glucose but also the multiple cardiovascular risk factors in these high-risk patients, including high blood pressure (BP), high blood cholesterol, smoking, and obesity (Table 1).

Figure

Hypertension and diabetes mellitus are common comorbidities that together result in a markedly increased risk for cardiovascular and renal complications.2 Hypertension is diagnosed in more than 50% of patients with diabetes mellitus,3,4 and diabetes mellitus is almost 2.5 times as likely to develop in people with hypertension as in normotensive individuals.4 Not only is each of these diseases a major risk factor for target organ disease, but they also work synergistically to increase morbidity and mortality.2 Recent epidemiologic data indicate that the risk of death due to cardiovascular disease in patients with type 2 diabetes mellitus is 2 to 4 times higher than in patients without diabetes mellitus.5 Up to 75% of cardiovascular and renal complications in patients with diabetes mellitus are attributable to hypertension.3

As reported by Saaddine et al,6 US population-based surveys, including the National Health and Nutrition Examination Survey conducted from 1988 to 1994, demonstrate that a gap exists between recommended diabetes care and the care that patients actually receive. Data from the 1999-2000 National Health and Nutrition Examination Survey demonstrate that only 25% of hypertensive diabetic patients had their BP controlled to less than 130/85 mm Hg and that only 31% of all hypertensive individuals had their BP controlled to less than 140/90 mm Hg.7

Aggressive control of BP in patients with diabetes mellitus will require the use of at least 2 agents in most patients.2,8-10 Effective control of hypertension in diabetic patients has a significant effect on mortality and morbidity; therefore, appropriate medication selection is an area of great interest to clinicians. A consensus has emerged that agents that block the reninangiotensin system (angiotensin-converting enzyme [ACE] inhibitors and angiotensin II receptor blockers) are among the most effective and safe drugs for lowering BP and for providing renal protection in hypertensive diabetic patients. Many studies demonstrate the efficacy of renin-angiotensin system blockers in slowing the development and progression of diabetic nephropathy and in reducing macrovascular and microvascular complications in hypertensive diabetic patients. Selection of one of these agents as first-line treatment is now established practice for all patients with diabetes mellitus.2,8-10

The primary goals of this study were to determine cardiovascular risk factors, level of BP control, and hypertension management strategies in patients with hypertension and type 2 diabetes mellitus enrolled in population-based healthcare settings. The then-current Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI)11 recommendation of a BP goal of less than 130/85 mm Hg for hypertensive diabetic patients was used.

METHODS

Study Population

From January 1, 1999, to December 31, 2001, medical and pharmacy claims data were collected from 10 insurance plans that provide healthcare coverage for more than 4 million people from 9 states (Alabama, California, Florida, Massachusetts, New York, Ohio, Oklahoma, Pennsylvania, and Texas). All patients 18 years and older with diagnoses of hypertension or type 2 diabetes mellitus as defined by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes or a pharmacy claim for an antihypertensive or antidiabetic agent within the past 12 months were assessed for inclusion in the database. Exclusion criteria were the use of antihypertensive agents for ischemic heart disease, myocardial infarction, congestive heart failure, arrhythmia, migraine, lower extremity edema, benign prostatic hypertrophy, and anxiety or panic disorder. Patients were excluded if they had renal failure or their medical record was not available. The population represented a regionally and ethnically diverse hypertensive population.

Data Collection and Analysis

This retrospective analysis was conducted as part of an ongoing multiphasic hypertension quality improvement program for participating health plans.12,13 A random sample of the hypertensive population was selected for medical chart review to confirm the diagnoses of hypertension and diabetes mellitus and to assess the prevalence of other cardiovascular disease risk factors, presence of comorbidities, and degree of BP control. The BP goal of less than 130/85 mm Hg was defined according to the then-current JNC VI11 guidelines for hypertensive patients with diabetes mellitus. Risk factors for cardiovascular disease, identified according to the same report, were smoking, dyslipidemia, age older than 60 years, sex (ie, male and postmenopausal female), and a family history of cardiovascular disease. Data on medication use were based on prescription claims, and medical chart reviews were used to confirm antihypertensive drug therapy; dyslipidemia and other comorbidities were identified using ICD-9-CM codes and medical chart documentation. Descriptive statistics were run for data on medication use and BP control collected during medical chart reviews. A minimum of 411 randomized medical charts was desired from each health plan, based on the 2-tailed test of significance between 2 proportions with α= .05 and 80% power. A total of 707 263 patients with hypertension were identified using electronic claims data; 4414 of these patients were randomly selected for medical chart review.

RESULTS

A diagnosis of type 2 diabetes mellitus was documented in 977 hypertensive patients. Their demographic characteristics, cardiovascular risk factors, and comorbidities are shown in Table 2. Most patients (87.5%) were overweight (25.3%), obese (50.3%), or morbidly obese (11.9%). Documented tobacco use was nearly 20%. Most patients were older than 60 years. Of the 977 patients, 19.7% had BP controlled to less than 130/85 mm Hg, and 13.8% had BP controlled to less than 130/80 mm Hg.

Figure

Prescription claim information was available from 787 patients (80.6%). Using claims data from the most recent month of the study, 299 patients (38.0%) had claims for 1 antihypertensive agent (single therapy), 264 patients (33.5%) had claims for 2 agents (dual therapy), and 193 patients (24.5%) had claims for 3 or more agents (multiple therapy). Analysis of BP control by number of prescriptions shows that most patients had uncontrolled hypertension, regardless of single, dual, or multiple therapy. There remains a significant opportunity for improvement in the treatment of hypertensive patients with diabetes mellitus.

The most commonly prescribed antihypertensive classes were ACE inhibitors (45.9%), followed by diuretics (36.3%), calcium channel blockers (33.0%), β-blockers (24.3%), angiotensin II receptor blockers (9.8%), α-blockers (7.0%), and other antihypertensive drugs (3.3%). Angiotensin-converting enzyme inhibitor-based regimens were prescribed for 404 patients (51.3%) and diuretic-based regimens for 352 patients (44.7%). Fixed-dose combination therapy with an ACE inhibitor or a calcium channel blocker accounted for 1.4% of prescriptions.

DISCUSSION

These data show that there is a large population of diabetic patients with hypertension receiving antihypertensive therapy in whom BP control remains inadequate. Furthermore, there is a need for more aggressive medical management of hypertensive diabetic patients, many of whom have other cardiovascular risk factors, including dyslipidemia, obesity, and family history of coronary artery disease.

Low rates of BP control are of concern given the evidence relating high BP to increased cardiovascular and renal disease in diabetic patients. Achieving target BP appears to present a unique challenge, and this study suggests that more aggressive treatment will be necessary to help patients in this high-risk population reach the appropriate BP goal. These data also suggest that numerous modifiable risk factors are not treated adequately according to 2001 American Diabetes Association treatment recommendations.14 These data can be used to identify and prioritize opportunities for improving the effectiveness of care in a high-risk population.

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