A survey of clinician attitudes and management practices in hypertension.

In order to determine the compliance of Canadian physicians with evidence-based hypertension guidelines, a self-administered questionnaire survey was distributed to a stratified random sample of 473 physicians in Central Alberta, Canada in December 1995. Excluding non-deliverable questionnaires, a response rate of 67% was obtained. Twenty-five per cent of respondents routinely used the fourth Korotkoff sound to define diastolic blood pressure (DBP). Investigations recommended for the initial workup of a patient with mild hypertension included serum creatinine (90%), electrolytes (72%), glucose (50%), cholesterol (44%), electrocardiogram (65%), and urinalysis (76%). The non-pharmacologic treatment advice routinely advocated for patients with mild hypertension included salt restriction (87%), weight loss (100%), and regular aerobic exercise (92%). While 46% of respondents recommended antihypertensive therapy for an otherwise healthy patient with an average DBP of 95 mm Hg, 76% recommended therapy for patients with the same BP plus target organ damage or other cardiovascular risk factors. Medication choices varied, although angiotensin-converting enzyme inhibitors were chosen by 46% for patients with uncomplicated essential hypertension and 67% for patients with other cardiovascular risk factors, and beta-blockers were the most frequently chosen first-line agents (56%) for the patient with target organ damage. There was considerable variability in the self-reported practice patterns, and concordance was greater for those recommendations which were consistent across the currently available guidelines. Consistent with the principle underlying all of the current hypertension guidelines, respondents were more aggressive in their treatment of hypertensive patients with other cardiovascular risk factors or target organ damage.

Parathyroid hypertensive factor predicts efficacy in the treatment of essential hypertension with verapamil.

Parathyroid hypertensive factor (PHF) is a circulating hypertensive factor, levels of which are inversely related to renin profile. Given this relationship, it was hypothesized that a PHF level might serve as an alternate predictor of antihypertensive efficacy in hypertensive patients, avoiding the difficulties associated with renin profiling. To test this hypothesis, thirty patients with essential hypertension were placed on 240 mg once daily of a slow release verapamil preparation for a period of one month following a one month run-in period. Results showed an average reduction in mean arterial pressure (MAP)of -7 mmHg (range -5 to - 18) and an average reduction in PHF of -4 mmHg (range 7 to -28). Pre-treatment PHF level correlated with the blood pressure response to verapamil (r = -0.61, p = 0.0004). There was no correlation between any index of renin status and blood pressure. The only other correlation of note was between normalized, ionized calcium and change in blood pressure (r = -0.46, p =0.02). In a forward stepwise multivariate model with MAP as the dependent variable, PHF and normalized, ionized calcium levels were the only biochemical or demographic predictors of response to verapamil. These results suggest that PHF level may be useful in determining the initial choice of antihypertensive agent in hypertensive patients.

Human immunodeficiency virus infection and porphyria cutanea tarda: coexistence of risk factors or causative association?

Several recent reports have described an association between human immunodeficiency virus (HIV) infection and porphyria cutanea tarda (PCT). We describe two HIV-infected patients who developed PCT and review 29 other reported cases of coexistent PCT and infection due to HIV. Recognized porphyrinogenic factors were identified in our patients and in 27 of the 29 cases described in the literature. Even in the two cases that lacked obvious precipitant factors for PCT, the possibility of hepatitis C was not excluded. This fact suggests that the co-occurrence of PCT and infection due to HIV may reflect the coexistence of risk factors for the two diseases rather than a causal association. Despite concern that exposure to sulfonamides might exacerbate porphyria, one of our patients and three patients described in the literature were safely treated with sulfonamides.

Pharmacokinetics of sotalol enantiomers in humans.

The chiral beta-blocker, sotalol (STL), is marketed as a racemic mixture. Although both STL enantiomers have equal Class III antiarrhythmic activity, beta-blocking activity has been ascribed mainly to the R-enantiomer. The pharmacokinetics of STL enantiomers were studied in young (mean age 32 +/- 3 years), healthy male volunteers after oral administration of 160 mg. Subsequent plasma and urine samples were collected over 24 hours, and STL enantiomer concentrations were determined using a stereospecific high-performance liquid chromatography assay. There were no significant differences between pharmacokinetic parameters of enantiomers. The area under the time-concentration curves (mean +/- standard deviation [SD]) were 6.95 +/- 0.85 and 6.76 +/- 1.2 (mg/L)hour for S- and R-STL, respectively. Maximal plasma concentrations of S- and R-STL were 615 +/- 167 and 619 +/- 164 ng/mL, respectively, which were obtained on average, 3.13 +/- 0.60 hours after dosing. The mean residence time (mean +/- SD) was 13.2 +/- 1.2 and 12.9 +/- 1.8 hours for S- and R-STL, respectively. Respective renal clearance values for S- and R-STL were 8.98 +/- 1.5 and 9.46 +/- 2.3 L/hour, and were approximately 1.5 times greater than creatinine clearance. Renal clearance constituted approximately 76% of the oral clearance. Although stereoselective disposition of STL was absent after racemate administration, these results should not be extrapolated to patients with significantly altered physiology, or to the pharmacokinetics of S-STL after administration of pure-S-STL.

The prevalence of humeral epicondylitis: a survey in general practice.

The characteristics of all patients with humeral epicondylitis who presented over a two-year period in a group practice were examined to clarify the epidemiological features of this condition. In all 77 patients were seen. There was no observed difference in incidence between the sexes, lateral epicondylitis being more common than medial in both sexes. Medial epicondylitis is more common in the community than is generally recognized. Epicondylitis is a relapsing condition with a strong bias towards the 35-54 years age group. Analysis revealed no relationship between incidence and socioeconomic class.