National Trends in the Prescribing of Anti-Hypertensive Medications

1. 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

2. 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

3. 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

4. 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)

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

6. Guidelines for HTN TreatmentJoint National Commission (JNC) on Prevention, Detection, Evaluation and Treatment of High Blood Pressure • JNC V recommendations (1993) • Diuretics and β-blockers should be used as preferred first-line medications • JNC VI recommendations (1997) • Diuretics and/or β-blockers should be used as first-line agents unless specific comorbidities compel selection of other drugs

7. 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)

8. 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

9. 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%

10. 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

11. Trends in Antihypertensive Prescribing, NAMCS JNC V JNC VI

12. Trends in Antihypertensive Prescribing, NHAMCS JNC V JNC VI

13. Trends in Prescribing of Diuretics, NAMCS JNC V JNC VI

14. Trends in Prescribing of Diuretics, NHAMCS JNC V JNC VI

15. Differences in Prescribing of Diuretics, NAMCS and NHAMCS

16. Differences in Prescribing of -Blockers, NAMCS and NHAMCS

17. 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

18. 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

19. Most Recent Trends in Antihypertensive Prescribing ALLHAT JNC VII

20. 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

21. 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

22. 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

23. 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

24. 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

25. 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

26. Thank You!