National Trends in the Prescribing of Anti-Hypertensive Medications

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National Trends in the Prescribing of
Anti-Hypertensive Medications

• Jun Ma, MD, PhD
• Research Associate
• Mentor Randall Stafford, MD, PhD
• Program on Prevention Outcomes and Practices

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Background

• Practice guidelines aim to guide physician
  practice according to the best available evidence
• Process of translating national guidelines and
  clinical evidence into public health benefit is
  complex
• Past studies suggest that guidelines are not
  necessarily being followed

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Background

• Diffusion of information from latest guidelines
  and clinical trial findings is suboptimal
• Despite the promise of new findings, adoption
  patterns may not always serve patients
• Use of medications lacking evidence of benefit
• Failure to use drugs with the strongest evidence
• Suggestion that sizable increase in drug costs
  has not provided a public health benefit

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Antihypertensive Prescribing Magnitude of the
Problem

• Elevated blood pressure is a major risk factor
  for heart diseases and stroke leading causes of
  death in the U.S.
• About 50 million Americans have elevated blood
  pressure with continued increases expected
• Antihypertensive medications cost 15 billion
  annually (10 of drug costs)

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Objective

• Examine the impact of JNC guidelines on
  antihypertensive prescribing by physicians in
  private practice and hospital outpatient clinics

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Guidelines for HTN TreatmentJoint National
Commission (JNC) on Prevention, Detection,
Evaluation and Treatment of High Blood Pressure

• JNC V recommendations (1993)
• Diuretics and ß-blockers should be used as
  preferred first-line medications
• JNC VI recommendations (1997)
• Diuretics and/or ß-blockers should be used as
  first-line agents unless specific comorbidities
  compel selection of other drugs

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Data Sources

• U.S. ambulatory care surveys 1993-2002 by
  National Center for Health Statistics
• National Ambulatory Medical Care Survey (NAMCS)
• Nationally representative sample of patient
  visits to office-based physicians
• National Hospital Ambulatory Medical Care Survey
  (NHAMCS)
• Nationally representative sample of patient
  visits to hospital outpatient departments (OPDs)

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Data Sources

• Multistage probability sampling procedures
• NAMCS PSU?Physicians?Patient Visits
• NHAMCS PSU?Hospitals?OPDs?Visits
• Annual participation rates
• NAMCS 63-73 of selected physicians
• NHAMCS 94-98 of selected hospitals
• Physician/staff-recorded information on standard
  patient encounter forms

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Study Sample

• Hypertensive visits patient visits having a
  principal diagnosis of essential HTN
• Sample size 645-1059(namcs)/809-1110(nhamcs)
• National estimates 23-49M/18-37M
• Antihypertensive drug visits hypertensive visits
  in which at least 1 antihypertensive drug was
  mentioned
• of hypertensive visits 65-80

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Antihypertensive Medication Classes

• Diuretics thiazides vs. other diuretics
• Beta/Alpha-Beta Blockers
• Calcium Antagonists
• ACE Inhibitors
• Angiotensin Receptor Blockers (ARBs)
• Alpha Blockers
• Central-Acting Alpha-Agonists
• Direct Vasodilators

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Trends in Antihypertensive Prescribing, NAMCS
JNC V
JNC VI
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Trends in Antihypertensive Prescribing, NHAMCS
JNC V
JNC VI
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Trends in Prescribing of Diuretics, NAMCS
JNC V
JNC VI
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Trends in Prescribing of Diuretics, NHAMCS
JNC V
JNC VI
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Differences in Prescribing of Diuretics, NAMCS
and NHAMCS
Diuretics
Sex (ref Female) Male 0.65 (0.55 0.77)
Race (ref White) African American 1.53 (1.23 1.91)
Age (ref 20-44 y) 45-59 60-74 75 1.42 (1.05 1.91) 1.47 (1.12 1.93) 1.73 (1.23 2.43)
Time (ref 93-97) 98-02 1.07 (0.89 1.29)
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Differences in Prescribing of ?-Blockers, NAMCS
and NHAMCS
?-Blocker
Sex (ref Female) Male 0.89 (0.74 1.07)
Race (ref White) African American 0.74 (0.57 0.95)
Age (ref 20-44 y) 45-59 60-74 75 1.01 (0.74 1.39) 0.88 (0.64 1.20) 0.86 (0.57 1.30)
Time (ref 93-97) 98-02 1.24 (1.01 1.51)
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Guidelines for HTN TreatmentJoint National
Commission (JNC) on Prevention, Detection,
Evaluation and Treatment of High Blood Pressure

• JNC VII recommendations (2003)
• Thiazide diuretics should be initial choice
  either alone or in combination with drugs of
  other classes
• ALLHAT (Antihypertensive and Lipid-Lowering
  Treatment to Prevent Heart Attack Trial) (Dec
  2002)
• Thiazide diuretics are at least as effective as
  the more expensive ACE inhibitors and CCBs in
  lowering blood pressure as well as cardiovascular
  events

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IMS Health Data

• National Disease and Therapeutic Index
• Nationally-based random sample of patient visits
  to office-based physicians
• Physician-reported data on new and continuing
  medications for each diagnosis per patient visit
• Annual sample size for HTN averaged 20,000

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Most Recent Trends in Antihypertensive Prescribing
ALLHAT
JNC VII
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Summary of Results

• Changes in antihypertensive prescribing are
  generally consistent with JNC recommendations and
  clinical evidence
• Increased prescribing of thiazide diuretics
• Increased prescribing of ?-blockers
• Declined prescribing of CCBs and more recently of
  ACE inhibitors

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Summary of Results

• Thiazides remain under prescribed despite most
  favorable cost-effectiveness
• Immediate upswing in thiazides following the
  ALLHAT publication in December 2002 did not
  sustain
• Impact of clinical evidence alone can be
  short-lived
• Efforts needed to encourage widespread adoption
  of evidence-based medicine

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Summary of Results

• CCBs and ACE inhibitors remain the most
  frequently prescribed antihypertensive drug
  classes
• Increasing popularity of ARBs
• More recent market entry and associated intense
  advertising

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Limitations

• Visit-based data may not reflect proportions of
  use in general population
• Lack of data necessary to assess treatment
  appropriateness at individual level
• Lack of data on patient compliance and outcomes

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Implications

• Need to foster more timely and complete
  dissemination of evidence-based guidelines
• Need to address physician adherence barriers
• Lack of awareness or familiarity with guidelines
• Lack of agreement with recommendations
• Attractiveness of new therapies and pressure to
  use the latest therapy

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Implications

• Need to shift focus from reducing blood pressure
  (single risk factor) to prevention of CVD
  (absolute risk)
• Need to assess the impact of evidence in the
  context of other factors that can influence
  prescribing practices

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Thank You!