Current therapeutic guidelines are based on randomized, controlled clinical trials showing that β blockers and diuretics can decrease the incidence of stroke and myocardial infarction in persons with primary hypertension. Because no such evidence exists for CCBs, they are not considered first-line agents. There is emerging evidence that at least one category of CCB may be harmful. Moreover, CCBs are more costly than β blockers or diuretics. Despite these drawbacks, many providers use CCBs as drugs of choice for hypertension. Attempts to understand and decrease unnecessary variance from evidence-based clinical practice guidelines in medical practice are central to recent initiatives in quality improvement and cost containment.
We demonstrated a significant effect on drug-prescribing habits in a general internal medicine clinic through the use of a simple computerized reminder system. This intervention resulted in 11.3% of intervention patients being changed to first-line antihypertensive agents, without change in control of their hypertension. We believe that this change rate is actually conservative, as the computer program misclassified 23% of patients who were prescribed these drugs for angina. By extending the exclusion for patients on nitrates to 2 years, another 66 patients (19.1%) would have been excluded from the study. None of these patients had their medications changed. Using these criteria, 14% of patients had their medications changed to first-line agents. Excluding patients that had any provider-reported contraindication, 23.6% of patients seen by intervention providers had therapy altered.
We also note that, at baseline, a larger number of patients in the intervention group were already on β blockers and ACE inhibitors, biasing the study against finding a significant effect of the intervention and making regression toward the mean an unlikely explanation of the findings. This study population included many patients with comorbid conditions, such as diabetes mellitus, hyperlipidemia, COPD, and benign prostatic hyperplasia, that might also bias providers against the use of either β blockers or diuretics. In other, healthier populations the rate of change might be expected to be higher because there would be fewer relative contraindications for the use of β blockers and diuretics.
This study also provides information on the reasons CCBs are used in a VA outpatient setting. Almost one quarter of patients were reported to have both hypertension and angina. In almost 10% of patients, CCBs were used for indications other than hypertension or angina, with chronic headache and arrhythmias accounting for most of these cases. Finally, by report of their physicians, almost 25% of patients either failed to obtain adequate BP control or had unacceptable adverse effects using β blockers or diuretics, suggesting failure rates for first-line therapy that are higher than reported in larger drug trials.
Our findings are consistent with past studies in demonstrating that an intervention can change provider prescribing behavior if it is individually targeted and delivered at the point of patient contact. It differs from past studies in showing that successful interventions need not be labor-intensive, as with academic detailing, but rather can rely on computer case finding to identify potentially modifiable prescribing patterns. The ability to design and implement an intervention that changes utilization without requiring extensive infrastructure or personnel makes it particularly attractive.
Though this trial was not designed for a formal cost analysis, we can make crude estimates of the cost of the study and the potential cost savings from drug changes. The computer program was developed in approximately 18 hours of programmer time, which would cost approximately $460. Each study day required approximately 10 minutes of time by the pharmacist to place the study insert in the patient chart. This time totals 16 hours over the 20-week study period, which would cost approximately $400. The total of direct costs was therefore less than $1,000. The total cost savings, calculated by subtracting the cost of the substituted drug from the previously prescribed CCB, was $7,140 for the 6-month period following the study. There was no evidence that providers ordered more laboratory tests or that patients had greater clinic utilization after their medications were changed. Full cost studies have shown that β blockers and diuretics are less expensive than CCBs for the treatment of hypertension, even when the costs of additional follow-up, laboratory testing, and treating any adverse effects are included.16
This intervention did require that the guideline reminder be manually placed in the patient chart after the patient was identified by a case-finding computer program. This protocol was adopted so that information on patients whose drug therapy was not changed could be gathered. If this type of intervention is adopted as an ongoing quality-improvement measure, the guideline reminder could be printed with the individual patient prescription refill forms currently printed in the clinic, thus fully automating the intervention.
Although this study was able to show clear changes in prescribing behavior through a simple intervention, it has several limitations. First, this study in a VA population may not be generalizable because of the relative homogeneity and high acuity of this population. The average patient in this trial was 63 years old and carried eight outpatient diagnoses in addition to hypertension. This may not represent most outpatient populations, but may represent an advantage because therapeutic changes would be more difficult in the setting of greater comorbidity and a larger number of special circumstances that might encourage the use of second-line antihypertensive agents.
Second, this intervention did not test for all areas of quality improvement, and did not examine patient outcomes or quality of life. Adverse drug effects are often cited as reasons for the failure of β blockers and diuretics in the treatment of hypertension. Several studies have concluded that quality of life rises with treatment for all classes of antihypertensive medication, and that no persistent differences in quality of life can be found between different classes of antihypertensive agents.17,18
Although this trial was not designed to test for changes in quality of life, there is no reason to believe that a differential in quality-of-life changes would have been seen.
Third, this trial was not designed to test for persistence of effect. In most settings, interventions that change provider behavior show decay of intervention effect over time. Although we were able to show that providers were willing to change prescribing habits when prompted at the patient-visit level, it is not clear whether this intervention actually changed long-term prescribing habits.
Finally, this trial was conducted in an academic setting. Providers in this setting may be more inclined to consider altering their practice style, particularly when prompted by a colleague. Though this effect cannot be ruled out, providers knew that the investigators were blinded to their identities throughout the trial. Providers in this setting may also be more influenced by recent negative literature on CCBs, though this effect would be seen in both control and intervention providers.
Our study shows that it is possible to use a simple, inexpensive, nonthreatening, computer-driven intervention to encourage treatment of hypertension in accordance with current recommendations. Similar interventions in other areas offer the potential to improve patient care with minimal implementation costs. When treatment according to guidelines can be cost-saving, as with hypertension, such programs could reach the elusive goal of simultaneously improving care while decreasing total health care costs.