Use of antihypertensive medications among United States veterans newly diagnosed with hypertension.

OBJECTIVES: Most patients with hypertension need combination therapy to reach adequate blood pressure control. The objective of this study was to assess type, duration of, and adherence to antihypertensive therapies among veterans, focusing on the use of combination therapies. RESEARCH DESIGN AND METHODS: The design of the study was a retrospective cohort analysis of electronic medical and pharmacy records from the Central Texas Veterans Health Care System (CTVHCS). Data were extracted for adults newly identified with hypertension between 1995 and 2003. Drug utilization was measured as a time-dependent variable; thus, the use of combination therapies was captured for any given day for each patient in the sample. Medication adherence was assessed using medication possession ratios (MPR), calculated by the number of days of therapy dispensed to a patient divided by the number of days between subsequent prescriptions. RESULTS: The average age of the participants (n = 11 187) was 60.7 (standard deviation (SD): 12.7). Half (50.1%) of the patients could be categorized as having controlled blood pressure. Veterans were followed for an average of 3.6 years (total of 51 549 person-years). Overall, 29 561 treatment episodes were identified, an average of about 2.6 per patient. Over 40% (41.6%) of these episodes involved one medication only, but patients frequently used dual (26.9%) and three or more (15.9%) therapies in combination. The frequency of prescribed antihypertensive therapies, as well as the length of, and adherence to, these therapies were described. Descriptively, medication adherence appeared to be lower among patients who received therapy for longer duration, indicating higher probability of missed doses and more frequent therapy changes. CONCLUSIONS: New information can be gained on the utilization of antihypertensive medications by using time-dependent variables. Understanding the type of combination therapies, the length of and adherence to these therapies, along with the observed blood pressure control rates will provide important new insights into the management of hypertensive patients. Limitations of the study arise primarily from the use of electronic medical records and the information that is contained within the datasource, and generalizability of the findings beyond the study sample.

A statistical and clinical evaluation of fingerstick and routine laboratory prothrombin time measurements.

STUDY OBJECTIVE: To compare prothrombin time measurements by fingerstick and routine laboratory methods. DESIGN: Prospective cohort study. SETTING: University-affiliated anticoagulation clinic. PATIENTS: Thirty-three patients receiving warfarin with stable anticoagulation for 3 months preceding the two studies. INTERVENTIONS: Groups 1 (17 patients) and 2 (16 patients) provided 150 and 125 paired samples, respectively, for fingerstick and routine laboratory analysis. The fact that no patient required a dosage change allowed for a clinical assessment. MEASUREMENTS AND MAIN RESULTS: Correlation and agreement between methods were good in group 1 but poor in group 2. Fingerstick results were less variable (smaller standard deviation and smaller coefficient of repeatability) in both groups. By analysis of discrepant pairs (25 in group 1, 63 in group 2), the routine laboratory results indicated dosage changes erroneously more often than did the fingerstick method. CONCLUSIONS: In these two trials, the fingerstick system was superior to the routine laboratory method in that it was more reliable (less variability and more repeatable) and less likely to indicate dosage changes erroneously.

Angiotensin-converting enzyme inhibitors in left ventricular dysfunction.

Angiotensin-converting enzyme (ACE) inhibitors have been used for more than a decade in the treatment of chronic congestive heart failure. In recent years these agents have been used in patients who survived a myocardial infarction. However, primary care providers are often confused as to which patients would benefit the most, and as a result, these life-prolonging drugs are underutilized. The results of randomized controlled trials evaluating ACE inhibitors' effect on morbidity and mortality in patients with chronic congestive heart failure or acute myocardial infarction were evaluated. Angiotensin-converting enzyme inhibitors clearly improve survival in patients with symptomatic congestive heart failure. This survival benefit is approximately 6 months. In patients with asymptomatic systolic dysfunction, these agents also decrease the number of hospital admissions due to heart failure. Angiotensin-converting enzyme inhibitors also improve survival in all patients who experienced an acute myocardial infarction. With the plethora of evidence regarding the positive effects that this class of drugs has on the quality of life and survival of patients with systolic dysfunction, it is still unclear why clinicians are reluctant to use them more often. Primary care providers need to be educated on how to risk stratify patients to make this therapy more cost effective, and when these agents should be started.

Potential warfarin-ciprofloxacin interaction in patients receiving long-term anticoagulation.

This study prospectively evaluated the potential interaction between the oral anticoagulant warfarin and the quinolone antimicrobial agent ciprofloxacin. After a 10-day placebo lead-in phase, 16 patients stabilized with long-term warfarin therapy were randomized to receive ciprofloxacin 500 mg or a matching placebo twice/day for 10 days. International normalized ratios (INRs) measured by both standard laboratory analysis and by Coumatrak (finger-stick) methods were evaluated at 3- to 5-day intervals. No patient experienced a significant increase in INR. No patient experienced a bleeding event. These data support the fact that a warfarin-ciprofloxacin interaction does not routinely occur at this dosage and duration of ciprofloxacin therapy.

The J-curve phenomenon and the treatment of hypertension. Is there a point beyond which pressure reduction is dangerous?

We critically appraised the medical literature to evaluate whether there is a point beyond which blood pressure reduction in hypertensive subjects is no longer beneficial and possibly even deleterious. Thirteen studies that stratified cardiovascular outcomes by level of achieved blood pressure in treated hypertensive subjects who had been followed up for at least 1 year were critiqued by four independent reviewers. Data addressing population, protocol, and methodological characteristics were evaluated. Studies did not show a consistent J-shaped relationship between treated blood pressure and stroke, but they did demonstrate a consistent J-shaped relationship for cardiac events and diastolic blood pressure. The beneficial therapeutic threshold point was 85 mm Hg. We conclude that low treated diastolic blood pressure levels, ie, below 85 mm Hg, are associated with increased risk of cardiac events.

Assessing quality of a diagnostic test evaluation.

OBJECTIVE: To develop a standardized scale for assessing the quality of a diagnostic test evaluation. DESIGN: Fourteen participants with formal and practical experience in evaluating diagnostic tests formed a consensus panel. Panel members identified and weighted questions that should be addressed when assessing the quality of a diagnostic test evaluation. SETTING: General internal medicine division at an academic medical center. RESULTS: A 19-item weighted scale was developed. It prioritizes and addresses issues such as description of the proposed purpose of the test; appropriate selection and description of the study population; appropriate performance and description of the diagnostic test; appropriate selection and performance of the reference standard; and adequate presentation of test characteristics. CONCLUSIONS: The scale is proposed as a useful instrument for readers, investigators, reviewers, and editors, because it represents an updated synthesis of important criteria to consider when evaluating diagnostic tests. It can also be used to rate quantitatively the quality of diagnostic test evaluations.

Captopril-stimulated renin secretion in the diagnosis of renovascular hypertension.

Evidence concerning the clinical utility of single dose captopril in the diagnosis of renovascular hypertension was evaluated. Of 173 identified papers, 16 were specifically selected because they used single dose oral captopril and obtained pre-dose and post-dose peripheral renin levels in at least one patient with renovascular hypertension. These 16 studies were appraised independently by three reviewers using standardized forms for evaluation of diagnostic tests. The 16 studies included 805 patients. All studies involved referred hypertensive populations; detailed demographics and clinical characteristics were not provided. Captopril test procedures varied in all studies. Thirteen of 16 studies used arteriography as a gold standard for the diagnosis of renovascular hypertension, and three of 16 used surgical outcome data. In ten studies, patients with renovascular hypertension clearly had a significantly greater increase in plasma renin activity than patients with essential hypertension. In the remaining six, plasma renin activity was increased in patients with renovascular hypertension but control comparisons were not made adequately. Existing data suggest that the captopril test may be useful in identifying patients with renovascular hypertension. However, specific clinical recommendations regarding its use cannot be made until future research better defines test cutoff points and identifies which patients are most likely to benefit from the test.

Relative efficacy of vasodilator therapy in chronic congestive heart failure. Implications of randomized trials.

We examined existing evidence concerning the relative efficacy of various vasodilator agents in chronic congestive heart failure. Only randomized placebo-controlled trials with clinical end points and treatment durations of four weeks or more were selected from an exhaustive search of the English-language medical literature. Twenty-eight trials involving 1976 patients were found. Treatment durations of the trials varied from one month to two years. Patients with symptomatic heart failure despite digitalis and diuretic therapy were studied; most were middle-aged men and approximately half had coronary artery disease. Results of the trials were appraised by three independent observers, and mortality and functional status outcomes were pooled in a meta-analysis. All vasodilator agents except hydralazine hydrochloride were associated with improvements in functional status. Angiotensin converting-enzyme inhibitors were the only agents associated with both decreased mortality (odds ratio, 0.51; 95% confidence interval, 0.34 to 0.75) and improved functional status (odds ratio, 4.53; 95% confidence interval, 3.46 to 5.92). The optimal timing for initiation of these agents was not established.