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

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

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

Patients and Methods: Patients 18 years and older with a medicalor pharmacy claim related to hypertension were identified andassessed for inclusion in the database. A random sample of medicalcharts was reviewed to confirm the diagnoses of hypertensionand diabetes mellitus and degree of BP control and to assess theprevalence of other cardiovascular disease risk factors and currentantihypertensive treatment.

Results: Type 2 diabetes mellitus was documented in 977patients. 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 achievedin 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 nottreated to their goal BP, which requires the use of 2 or more agentsin most patients. Quality improvement programs should emphasizethe importance of treating hypertensive diabetic patients to theirgoal BP, as well as controlling other major cardiovascular diseaserisk 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 DiabetesAssociation reports that cardiovascular disease isa major unrecognized problem in patients withtype 2 diabetes mellitus in the United States.¹ Whileheart disease and stroke are the leading causes of deathamong people with diabetes mellitus, 68% of diabeticpatients are not aware of the significant risk posed bycardiovascular disease. Fortunately, more than 90% ofphysicians surveyed are aware of the link between diabetesmellitus and cardiovascular disease, althoughthere is recognition of the need to become more aggressivein treating not only blood glucose but also the multiplecardiovascular risk factors in these high-riskpatients, including high blood pressure (BP), high bloodcholesterol, smoking, and obesity (Table 1).

Hypertension and diabetes mellitus are commoncomorbidities that together result in a markedlyincreased risk for cardiovascular and renal complications.² Hypertension is diagnosed in more than 50% ofpatients with diabetes mellitus,^3,4 and diabetes mellitusis almost 2.5 times as likely to develop in people withhypertension as in normotensive individuals.⁴ Not onlyis each of these diseases a major risk factor for targetorgan disease, but they also work synergistically toincrease morbidity and mortality.² Recent epidemiologicdata indicate that the risk of death due to cardiovasculardisease in patients with type 2 diabetes mellitus is2 to 4 times higher than in patients without diabetesmellitus.⁵ Up to 75% of cardiovascular and renal complicationsin patients with diabetes mellitus are attributableto hypertension.³

As reported by Saaddine et al,⁶ US population-basedsurveys, including the National Health and NutritionExamination Survey conducted from 1988 to 1994,demonstrate that a gap exists between recommendeddiabetes care and the care that patients actuallyreceive. Data from the 1999-2000 National Health andNutrition Examination Survey demonstrate that only25% of hypertensive diabetic patients had their BP controlledto less than 130/85 mm Hg and that only 31% ofall hypertensive individuals had their BP controlled toless than 140/90 mm Hg.⁷

Aggressive control of BP in patients with diabetesmellitus will require the use of at least 2 agents in mostpatients.^2,8-10 Effective control of hypertension in diabeticpatients has a significant effect on mortality andmorbidity; therefore, appropriate medication selectionis an area of great interest to clinicians. A consensushas emerged that agents that block the reninangiotensinsystem (angiotensin-converting enzyme[ACE] inhibitors and angiotensin II receptor blockers)are among the most effective and safe drugs forlowering BP and for providing renal protection inhypertensive diabetic patients. Many studiesdemonstrate the efficacy of renin-angiotensin systemblockers in slowing the development and progressionof diabetic nephropathy and in reducingmacrovascular and microvascular complications inhypertensive diabetic patients. Selection of one ofthese agents as first-line treatment is now establishedpractice for all patients with diabetes mellitus.^2,8-10

The primary goals of this study were to determinecardiovascular risk factors, level of BP control,and hypertension management strategies inpatients with hypertension and type 2 diabetes mellitusenrolled in population-based healthcare settings.The then-current Sixth Report of the JointNational Committee on Prevention, Detection,Evaluation, and Treatment of High Blood Pressure(JNC VI)¹¹ recommendation of a BP goal of less than130/85 mm Hg for hypertensive diabetic patientswas used.

METHODS

Study Population

International Classification

of Diseases, Ninth Revision, Clinical

Modification (ICD-9-CM)

From January 1, 1999, to December 31, 2001, medicaland pharmacy claims data were collected from 10insurance plans that provide healthcare coverage formore than 4 million people from 9 states (Alabama,California, Florida, Massachusetts, New York, Ohio,Oklahoma, Pennsylvania, and Texas). All patients 18years and older with diagnoses of hypertension or type 2diabetes mellitus as defined by codes or a pharmacy claim foran antihypertensive or antidiabetic agent within the past12 months were assessed for inclusion in the database.Exclusion criteria were the use of antihypertensiveagents for ischemic heart disease, myocardial infarction,congestive heart failure, arrhythmia, migraine, lowerextremity edema, benign prostatic hypertrophy, andanxiety or panic disorder. Patients were excluded if theyhad renal failure or their medical record was not available.The population represented a regionally and ethnicallydiverse hypertensive population.

Data Collection and Analysis

ICD-9-CM

This retrospective analysis was conducted as part ofan ongoing multiphasic hypertension quality improvementprogram for participating health plans.^12,13 A randomsample of the hypertensive population was selectedfor medical chart review to confirm the diagnoses ofhypertension and diabetes mellitus and to assess theprevalence 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 definedaccording to the then-current JNC VI¹¹ guidelines forhypertensive patients with diabetes mellitus. Risk factorsfor cardiovascular disease, identified according tothe same report, were smoking, dyslipidemia, age olderthan 60 years, sex (ie, male and postmenopausalfemale), and a family history of cardiovascular disease.Data on medication use were based on prescriptionclaims, and medical chart reviews were used to confirmantihypertensive drug therapy; dyslipidemia and othercomorbidities were identified using codesand medical chart documentation. Descriptive statisticswere run for data on medication use and BP control collectedduring medical chart reviews. A minimum of 411randomized medical charts was desired from eachhealth plan, based on the 2-tailed test of significancebetween 2 proportions with α= .05 and 80% power. Atotal of 707 263 patients with hypertension were identifiedusing electronic claims data; 4414 of these patientswere randomly selected for medical chart review.

RESULTS

A diagnosis of type 2 diabetes mellitus was documentedin 977 hypertensive patients. Their demographiccharacteristics, cardiovascular risk factors, andcomorbidities are shown in Table 2. Most patients(87.5%) were overweight (25.3%), obese (50.3%), ormorbidly obese (11.9%). Documented tobacco usewas nearly 20%. Most patients were older than 60years. Of the 977 patients, 19.7% had BP controlledto less than 130/85 mm Hg, and 13.8% had BP controlledto less than 130/80 mm Hg.

Prescription claim information was availablefrom 787 patients (80.6%). Using claims data fromthe most recent month of the study, 299 patients(38.0%) had claims for 1 antihypertensive agent(single therapy), 264 patients (33.5%) had claims for2 agents (dual therapy), and 193 patients (24.5%)had claims for 3 or more agents (multiple therapy).Analysis of BP control by number of prescriptionsshows that most patients had uncontrolled hypertension,regardless of single, dual, or multiple therapy.There remains a significant opportunity forimprovement in the treatment of hypertensivepatients with diabetes mellitus.

The most commonly prescribed antihypertensiveclasses were ACE inhibitors (45.9%), followed bydiuretics (36.3%), calcium channel blockers (33.0%),β-blockers (24.3%), angiotensin II receptor blockers(9.8%), α-blockers (7.0%), and other antihypertensivedrugs (3.3%). Angiotensin-converting enzymeinhibitor-based regimens were prescribed for 404patients (51.3%) and diuretic-based regimens for352 patients (44.7%). Fixed-dose combination therapywith an ACE inhibitor or a calcium channelblocker accounted for 1.4% of prescriptions.

DISCUSSION

These data show that there is a large population ofdiabetic patients with hypertension receiving antihypertensivetherapy in whom BP control remains inadequate.Furthermore, there is a need for moreaggressive medical management of hypertensive diabeticpatients, many of whom have other cardiovascularrisk factors, including dyslipidemia, obesity,and family history of coronary artery disease.

Low rates of BP control are of concern giventhe evidence relating high BP to increased cardiovascularand renal disease in diabetic patients. Achievingtarget BP appears to present a unique challenge, andthis study suggests that more aggressive treatmentwill be necessary to help patients in this high-riskpopulation reach the appropriate BP goal. These dataalso suggest that numerous modifiable risk factors arenot treated adequately according to 2001 AmericanDiabetes Association treatment recommendations.¹⁴These data can be used to identify and prioritizeopportunities for improving the effectiveness of carein a high-risk population.

P

The low rates of effective treatment relative to riskfactor goals are similar to those of other studies^15-20among diabetic patients. For example, a recent study¹⁵ of601 randomly selected patients with type 2 diabetesmellitus demonstrated that the proportions of patientsscreened for hypercholesterolemia and hypertensionand treated aggressively for above-goal BP (78%) andlow-density lipoprotein cholesterol levels (38%) were significantlylower than for hyperglycemia treatment (92%)(<.001). These results are echoed in another study²⁰that compared 274 hypertensive patients with diabetesmellitus and 526 hypertensive patients without diabetesmellitus and showed that patients with diabetes mellitusreceived less intensive treatment and had worse BP controlthan the patients without diabetes mellitus.

In our study, patients had a mean body mass index(calculated as weight in kilograms divided by the squareof height in meters) of 32. Obesity, defined as a bodymass index of 30 or higher, is associated with increasedmortality from coronary artery disease and a 50% to100% increased risk of death from all causes (but primarilyfrom cardiovascular disease) compared withpatients with a body mass index of 20 to 25.²¹ Currentguidelines include an emphasis on the value of exercisein contributing to weight loss and reduction of cardiovascularrisk factors.¹⁰ For example, a recent study²² ina cohort of 2896 adults with diabetes mellitus showedthat regularly walking 30 minutes per day was associatedwith a 50% reduction in cardiovascular and totalmortality.

In our study, tobacco use was documented in nearly20% of patients. Cigarette smoking is the leading preventablecause of death and a major risk factor for cardiovasculardisease, and the use of effective strategies toreduce the prevalence of tobacco use is therefore a highpriority for primary and secondary prevention of cardiovasculardisease. Every smoker should be urged toquit. Routine practice of diabetes care must incorporatethe use of effective systems (screening for smoking status;advice, counseling, and support regarding cessation;and follow-up) for implementing smokingcessation guidelines.²³

Diabetic patients with coronary artery disease, dyslipidemia,or heart failure may need as many as 9 separatemedications each day. Diabetes mellitus itself oftenrequires 2 to 3 separate daily medications.¹⁷ Hypertensivediabetic patients may require at least 2 to perhaps5 separate drugs to achieve a BP goal of 130/80 mmHg.²⁴ Complex multiple drug regimens are needed tocontrol these numerous comorbidities in hypertensivediabetic patients, including the need for rigorous controlof BP. Because renin-angiotensin system blockadeshould be the initial therapeutic intervention, a logicalapproach to lowering BP is to combine a low-dose diureticwith an ACE inhibitor or an angiotensin II receptorblocker.^8,25,26 In addition, evidence from randomizedcontrolled trials shows that calcium channel blockersreduce cardiovascular events in patients with diabetesmellitus; these drugs are a safe and effective addition toa renin-angiotensin system blocker to further improveBP control.^8,25 It is increasingly recognized that loweringBP to target levels should be the overwhelming primaryobjective, regardless of the therapeutic agents chosen forantihypertensive combination therapy.^8,25,26

The percentage of patients achieving BP control inthis study differs slightly from that in other reports. Forexample, the nationally representative sample of thecivilian population from the National Health andNutrition Examination Survey shows a rate of BP controlof 25.4% in patients with hypertension and diabetesmellitus.⁷ In contrast, this study includes patients from9 US states, and the findings can be generalized only tothe patient population receiving therapy as reported inthe pharmacy or medical claims database, which mayaccount for the lower (19.7%) BP control rate.

As with all retrospective analyses of claims databasesand medical charts, this study has several limitations.First, the study population included only patients coveredby health insurance; therefore, the results may notbe generalizable to the general population or to otherhealthcare settings. Coding errors or lack of documentationin medical charts may have resulted in missingdata or the exclusion of some hypertensive patientswith diabetes mellitus. It was outside the scope of thestudy to include lipid or hemoglobin A_1c values.Although these data were not available, clinical variablesconcerning risk factors and the prevalence ofcomorbid conditions were gathered to interpret theresults of this study. Finally, as the JNC VI¹¹ guidelineswere in effect during the study, it was not possibleto measure the effect of subsequent guidelineson the treatment of hypertensive patients with diabetesmellitus and the ability of these patients toreach BP control given the new goal and treatmentrecommendations.

Based on the data generated from this analysis, the10 health plans that contributed data to this study aredeveloping organization-wide intervention programsthat include the following: (1) education sessions forpractitioners that focus on the importance of treatingpatients to goal and choosing optimal antihypertensivetherapy, (2) medical management guidelines for practitioners,(3) physician profiling of prescribing patterns,(4) BP monitoring kits for patients, and (5) patient education.Each plan will continue follow-up for 1 year toevaluate the effect of the intervention initiative.

CONCLUSIONS

The high mortality and morbidity rates for patientswith coexisting diabetes mellitus and hypertensionindicate the need for aggressive treatment to lower BP.The recommended BP goal of less than 130/80 mm Hgrequires the use of 2 or more agents in most patients. Itappears that diabetic patients frequently are not treatedto their BP goal. Antihypertensive treatment must beaggressive and strategically used early and intensively,yet it must be simultaneously practical to meet the challengeof protecting hypertensive diabetic patientsagainst the risk of cardiovascular complications.Furthermore, intensified efforts must be given to modificationof other major cardiovascular risk factors in diabeticpatients, such as smoking, dyslipidemia, andoverweight or obesity, that are prevalent among thesehigh-risk patients.

From The University of Texas at Austin College of Pharmacy (PJG); Applied HealthOutcomes, Palm Harbor, Fla (SKM, EWF); and Novartis Pharmaceuticals Corporation, EastHanover, NJ (FF).

This study was funded by a grant from Novartis Pharmaceuticals Corporation. Anabstract of this study was presented at the 61st Scientific Sessions of the American DiabetesAssociation; June 24, 2001; Philadelphia, Pa.

Address correspondence to: Susan K. Maue, PhD, Applied Health Outcomes, 3488East Lake Road, Suite 201, Palm Harbor, FL 34685. E-mail: smaue@applied-outcomes.com.

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