Quantifying Risk of Adverse Clinical Events With One Set of Vital Signs Among Primary Care Patients with Hypertension

Abstract

BACKGROUND Hypertension is often uncontrolled. One reason might be physicians' reticence to modify therapy in response to single offi ce measurements of vital signs. METHODSUsing electronic records from an inner-city primary care practice, we extracted information about vital signs, diagnoses, test results, and drug therapy available on the fi rst primary care visit in 1993 for patients with hypertension. We then identifi ed multivariable predictors of subsequent vascular complications in the ensuing 5 years. RESULTSOf 5,825 patients (mean age 57 years) previously treated for hypertension for 5.6 years, 7% developed myocardial infarctions, 17% had strokes, 24% developed ischemic heart disease, 22% had heart failure, 12% developed renal insuffi ciency, and 13% died in 5 years. Controlling for other clinical data, a 10-mmHg increase in systolic blood pressure was associated with 13% increased risk (95% confi dence interval [CI], 6%-21%) of renal insuffi ciency, 9% (95% CI, 3%-15%) increased risk of ischemic heart disease, 7% (95% CI, 3%-11%) increased risk of stroke, and 6% (95% CI, 2%-9%) increased risk of fi rst stroke or myocardial infarction. A 10-mmHg elevation in mean blood pressure predicted a 12% (95% CI, 5%-20%) increased risk of heart failure. An increase in heart rate of 10 beats per minute predicted a 16% (95% CI, 2%-5%) increased risk of death. Diastolic blood pressure predicted only a 13% (95% CI, 4%-23%) increased risk of fi rst stroke.CONCLUSIONS Vital signs-especially systolic blood pressure-recorded routinely during a single primary care visit had signifi cant prognostic value for multiple adverse clinical events among patients treated for hypertension and should not be ignored by clinicians. INTRODUCTIONA dverse cardiovascular events are the leading cause of death in developed nations. Their prevention and treatment consume a large proportion of national health care expenditures. Hypertension, a wellknown modifi able risk factor for adverse cardiovascular events, is among the most common conditions treated in primary care. Yet, hypertension is often inadequately controlled, 1-4 which adds to dramatic costs in terms of dollars and lost years of life as a result of preventable cardiovascular events. 5 One possible reason for inadequate control is physicians' ignoring elevated blood pressure readings. Blood pressure can vary substantially throughout the day, 6,7 and offi ce pressures correlate poorly with and confer less cardiovascular risk than ambulatory blood pressure readings. 8,9 Indeed, guidelines for detecting and treating hypertension require multiple blood pressure elevations, 1 reinforcing the notion that single measurements of blood pressure may not require a physician' s response. William M Tierney, MD 210 RISK OF ADVERSE EVENTS FOR HYPERTENSIONThere is also controversy concerning which vital signs (specifi cally blood pressure and heart rate), or their combinations, were prognostic. For example, systolic pressure has been shown to predict myocardial infarctions, strokes, rena...

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“…Only in the case group (CV death) was resting BP ≥ 140/90 mmHg significant, and the patients who died were 1.20 times more likely to have increased blood pressure. The impact of elevated heart rate on hypertensive as well as diabetic patients, increasing by three-to-four-fold the risk of cardiovascular events and twice the risk of dying from such an event, compared to the general population, is already well documented in the literature 4,26,27 . The adrenergic hyperactivity involved in these risk factors and the imbalance between the sympathetic and parasympathetic activities explain these findings 2 .…”

Electronic Data Collection Options for Practice-Based Research Networks

“…25 This system has been in operation since 1972 and contains hundreds of millions of discrete coded observations, although many of these data originate from specialist or hospital care. 26 The Regenstrief Medical Record System has been a rich source of clinical data, resulting in hundreds of articles in the past 4 years alone.…”

“…With access to data extending back for many years, powerful epidemiologic studies from primary care practices are emerging. 25 Henk Lamberts and Inge Hofmans-Okkes 27 created an episode-oriented EHR system, called Transhis, that is used by a network of general practitioners in the Netherlands. In this system, the application of the International Classifi cation for Primary Care (ICPC) is the guiding principle to structure episode-oriented epidemiology.…”

Improving Health Care Locally and Globally

“…The study of the predictive value of a single set of vital signs by Tierney et al 5 is generating an enlightening back-and-forth discussion between readers and the author. This discussion (which can be found by clicking on the Published Track Comments in the upper-right corner of the full-text article at http://www.annfammed.…”