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Biomedical subjects

M H Criqui

Publications and source records attributed to M H Criqui.

At least 19 recordsLinked to original sources

Leg symptoms, the ankle-brachial index, and walking ability in patients with peripheral arterial disease.

OBJECTIVE: To determine how functional status and walking ability are related to both severity of lower extremity peripheral arterial disease (PAD) and PAD-related leg symptoms. DESIGN: Cross-sectional study. SETTING: Academic medical center. PARTICIPANTS: Patients aged 55 years and older diagnosed with PAD in a blood flow laboratory or general medicine practice (n = 147). Randomly selected control patients without PAD were identified in a general medicine practice (n = 67). MEASUREMENTS: Severity of PAD was measured with the ankle-brachial index (ABI). All patients were categorized according to whether they had (1) no exertional leg symptoms; (2) classic intermittent claudication; (3) exertional leg symptoms that also begin at rest (pain at rest), or (4) exertional leg symptoms other than intermittent claudication or pain at rest (atypical exertional leg symptoms). Participants completed the 36-Item Short-Form Health Survey (SF-36) and the Walking Impairment Questionnaire (WIQ). The WIQ quantifies patient-reported walking speed, walking distance, and stair-climbing ability, respectively, on a scale of 0 to 100 (100 = best). MAIN RESULTS: In multivariate analyses patients with atypical exertional leg symptoms, intermittent claudication, and pain at rest, respectively, had progressively poorer scores for walking distance, walking speed, and stair climbing. The ABI was measurably and independently associated with walking distance (regression coefficient = 2.87/0.1 ABI unit, p =.002) and walking speed (regression coefficient = 2.09/0.1 ABI unit, p =.015) scores. Among PAD patients only, pain at rest was associated independently with all WIQ scores and six SF-36 domains, while ABI was an independent predictor of WIQ distance score. CONCLUSIONS: Both PAD-related leg symptoms and ABI predict patient-perceived walking ability in PAD.

Aged

Epidemiologic aspects of lipid abnormalities.

Existing cholesterol guidelines aimed at preventing cardiovascular disease emphasize the role of total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol in lipid management decisions, with a subsidiary role for high-density lipoprotein (HDL) cholesterol in guiding treatment and little role for triglycerides. In this article, epidemiologic evidence is reviewed relating to the independent value of lipid factors in prediction of cardiovascular disease risk, including TC, LDL cholesterol, HDL cholesterol, very-low-density lipoprotein (VLDL) cholesterol and triglycerides, LDL particle size ("pattern B"), and the TC/HDL-cholesterol ratio. Several observations are highlighted. Triglycerides appear to be an independent risk factor in specific populations. Postprandial triglycerides may be superior to fasting triglycerides as a predictor of risk. LDL particle size does not have independent predictive value after adjustment for triglycerides. Particular emphasis is placed on the observation that the single most predictive lipid factor is the TC/HDL-cholesterol ratio, which implicitly incorporates information on both LDL and triglycerides in the numerator. This is the best predictor both of outcome and of treatment benefit, and its predictive value appears to be maintained into older age. It is concluded that increasing emphasis should be placed on the TC/HDL cholesterol ratio in epidemiologic analyses and in monitoring patients on therapy for dyslipidemia.

Age Distribution

Do known cardiovascular risk factors mediate the effect of alcohol on cardiovascular disease?

The association between alcohol intake and atherosclerotic cardiovascular disease (CVD) in epidemiological studies is consistent and shows some protection from CVD at consumption levels of one to two drinks per day, but a sharp increase in CVD associated with three or more drinks per day. Analyses of potential mediators of effects of alcohol on CVD show that it increases high density lipoprotein (HDL) cholesterol levels and favourably influences thrombotic factors, especially fibrinogen, and also fibrinolytic factors. Some evidence also suggests moderate alcohol consumption may reduce insulin resistance. However, studies also show an adverse effect of alcohol, particularly at higher doses, on blood pressure (leading to hypertension) and directly on the myocardium (leading to arrhythmias and myocardiopathy). Statistical modelling of the alcohol-CVD relationship is consistent in several studies, with a protective pathway via elevated HDL cholesterol and an adverse pathway through elevated blood pressure. Other possible mediators influenced by alcohol have not yet been examined in this type of analysis. The French Paradox has led to speculation that wine is the only protective alcoholic beverage for CVD, or at least that it has a stronger effect. Multiple non-ethanol components of wine have been studied in the laboratory and have been shown to have antioxidant or anticoagulant effects. Although wine does appear more protective in ecological studies, studies within cohorts show similar effects across alcoholic beverages, suggesting confounding in ecological studies by diet, lifestyle, or other variables. The key component of alcoholic beverages thus appears to be ethanol, consistent with the known potent effects of ethanol on HDL cholesterol and thrombotic factors. The upswing in CVD risk with three or more drinks per day is sharp and emphasizes that benefit from alcohol is limited to moderate consumption only. This upswing also cautions against any public health recommendation to drink alcohol, since many persons will not or cannot limit their intake to moderate levels.

Alcohol Drinking

Measurement of walking endurance and walking velocity with questionnaire: validation of the walking impairment questionnaire in men and women with peripheral arterial disease.

OBJECTIVES: The Walking Impairment Questionnaire (WIQ) was designed to measure community walking ability in patients with peripheral arterial disease (PAD) and intermittent claudication. We compared the WIQ scores to objective measures of walking in a heterogeneous group of patients with and without PAD. METHODS: The study was designed as a cross-sectional study, with the setting in an academic medical center. The subjects were patients with PAD (n = 145) who were identified from a noninvasive vascular laboratory at an academic medical center. The patients without PAD (n = 65) were identified from a general medicine practice. The average number of comorbidities was 2.03 for patients with PAD and 1.52 for patients without PAD. Among the patients with PAD, 28% had classical intermittent claudication symptoms and 55% had exertional leg symptoms other than claudication. The main outcome measures were the WIQ estimates of the patient-reported walking distance and walking speed on a scale of 0 to 100. Walking endurance was measured objectively with the 6-minute walk. Walking velocity was measured with a 4-m walk. PAD and PAD severity were defined with the ankle brachial index. RESULTS: The Spearman rank correlation coefficients (rho) between the WIQ distance score and the 6-minute walk score were 0.557 among patients with PAD (P <.001) and 0.484 among patients without PAD (P <.001). The correlation coefficients between the WIQ speed score and the usual-paced 4-m walk score were 0.528 among patients with PAD (P <.001) and 0.524 among patients without PAD (P <.001). The correlations were not affected by the presence versus the absence of intermittent claudication, by PAD severity, or by the presence of 2 or more versus less than 2 comorbid illnesses. The WIQ scores in the highest and lowest quartiles were the most closely associated with the objective measures of function. CONCLUSION: The WIQ is a valid measure of community walking ability in a heterogeneous group of patients with and without PAD. The WIQ discriminates best among patients in the highest and the lowest quartiles of walking speed and endurance.

Aged

The ankle brachial index independently predicts walking velocity and walking endurance in peripheral arterial disease.

OBJECTIVES: Maintaining function among older men and women is an important public health goal as the population lives longer with chronic disease. We report the relationships between lower extremity peripheral arterial disease (PAD), PAD severity, and PAD-related symptoms with walking velocity and endurance among men and women aged 55 and older. DESIGN: A cross-sectional design. SETTING: An academic medical center. PARTICIPANTS: Participants with PAD were men and women aged 55 and older identified from a blood flow laboratory or a general medicine practice (n = 158). Randomly selected controls without PAD were identified from the general medicine practice (n = 70). MEASUREMENTS: PAD was diagnosed and quantified using the ankle brachial index (ABI). Subjects were categorized according to whether they had severe PAD (ABI <0.40), mild to moderate PAD (ABI 0.40 to <0.90), or no PAD (ABI 0.90 to <1.50). Walking endurance was assessed with the 6-minute walk. Usual walking velocity and maximal walking velocity were assessed with "usual" and "maximal" paced 4-meter walks, respectively. RESULTS: Average distances achieved in the 6-minute walk were 1569+/-390 feet for subjects with ABI 0.90-1.50, 1192+/-368 feet for subjects with ABI 0.40 to <0.90, and 942+/-334 feet for subjects with ABI < 0.40 (trend P value < .001). Walking velocities for both the usual and maximal paced 4-meter walks were slowest among subjects with ABI < 0.40 and fastest among subjects with ABI 0.90 to <1.50. Subjects with PAD who had pain at rest had slower walking velocity and poorer walking endurance than other subjects with PAD. In multiple linear regression analyses that included subjects with PAD only, ABI level was an independent predictor of 6-minute walk performance (regression coefficient = 159 ft/0.40 ABI units, P = .011), usual paced 4-meter walk (regression coefficient = .095 meters/sec/0.40 ABI units, P = .031), and maximal paced 4-meter walk (regression coefficient = .120 meters/sec/0.40 ABI units, P = .050) adjusting for age, sex, race, leg symptoms, and comorbid diseases known to affect functioning. Pain at rest was associated independently with the maximally paced 4-meter walk (-0.201 meters/sec, P = .024), but not with the other walks. CONCLUSION: ABI level has a measurable and independent association with walking endurance and both usual and maximal walking velocity. These data suggest that PAD may impair lower extremity function by diminishing function of both Type I ("slow twitch") and Type II ("fast twitch") muscle fibers. Because walking velocity has important prognostic implications for functioning, these data also suggest that ABI may be used to identify patients at increased risk of mobility loss.

Aged

The generalized nature of atherosclerosis: how peripheral arterial disease may predict adverse events from coronary artery disease.

Non-invasive measurements, especially segmental pressure ratios and flow measurements, are useful for gauging the severity of peripheral arterial disease (PAD). Although the incidence of PAD is similar for men and women, men are more likely to have severe disease, while women usually have more moderate or asymptomatic disease. Published reports confirm the clinical impression that patients with PAD are more likely to have both coronary artery disease and cerebrovascular disease than those without PAD. However, the degree of overlap is a function of the sensitivity of the diagnostic assessments for the three conditions. A San Diego population study found that the incidence of PAD may be underestimated, with many patients being asymptomatic. Based on blood flow measurements, the study found that 11.9% of the study population had large vessel PAD. Morbidity from both coronary heart disease and stroke was increased in people with PAD, who were 2.5 times more likely to present with morbidity from cardiovascular disease (CVD) than those who did not have PAD. Several studies have now confirmed the strong predictive value of PAD for subsequent CVD mortality and that the risk of CVD mortality increases with the severity of PAD.

Adult

Triglycerides and cardiovascular disease. A focus on clinical trials.

Observational studies, both case control and prospective, have routinely identified elevated triglycerides as a univariate predictor of cardiovascular disease, especially coronary heart disease, and in several studies this association persists in multivariate analysis. However, experimental information from clinical trials is required for clinical guidelines. Many clinical trials in dyslipidaemia have employed interventions with only minor effects on triglycerides. Five trials have used pharmaceutical agents with significant triglyceride effects and have correlated the clinical or angiographic benefit observed with the change in various lipid or lipoprotein components. In three of these five trials, the benefit for various coronary disease endpoints was more closely associated with triglyceride reductions than with changes in other lipids and lipoproteins. A sixth trial showed reduced coronary disease progression with treatment despite no change in LDL cholesterol. Reduction in triglycerides may result in direct benefit for coronary disease. Clinical trials employing pharmacological agents with significant effects on triglycerides should correlate clinical and/or angiographic benefit with observed lipid and lipoprotein changes, as well as any changes in non-lipid risk factors such as fibrinogen.

Bezafibrate

When to start cholesterol-lowering therapy in patients with coronary heart disease. A statement for healthcare professionals from the American Heart Association Task Force on Risk Reduction.

At present a large number of patients with atherosclerotic disease are not receiving aggressive cholesterol-lowering therapy. Consequently they are being deprived of a cost-effective, risk-reducing treatment. Every physician who treats patients with clinical atherosclerotic disease should become fully informed about the results of cholesterol-lowering trials in patients at high risk. All physicians who care for high-risk patients should take responsibility for cholesterol management, including primary care physicians and cardiovascular specialists. Highly effective and generally safe drugs for cholesterol lowering are available. The benefits of therapy for reducing recurrent CHD and prolonging life are considerable. There is no justification for unduly delaying institution of therapy for the majority of patients. The many advantages of nonpharmaceutical therapy call for its use in almost all patients, but drug treatment should not be postponed if the target for LDL cholesterol lowering (< or = 100 mg/dL) is unlikely to be achieved in the near term by a nonpharmaceutical approach alone. The view that patients with CHD or other forms of atherosclerotic disease do not receive substantial clinical benefits from aggressive cholesterol-lowering therapy is no longer warranted. Intensive cholesterol reduction, initiated immediately, has the potential to significantly reduce both morbidity and mortality. Cholesterol-lowering therapy thus should become a routine part of clinical management to reduce risk of future coronary events and to prolong life in patients with CHD or other forms of atherosclerotic disease.

Anticholesteremic Agents

Parental divorce: effects on individual behavior and longevity.

Using an archival prospective design, the authors studied associations among parental divorce occurring during participants' childhood, adult psychosocial mediators, and mortality over the life span of a subgroup of participants (N = 1,261) in the Terman Life Cycle Study (1921-1991). Children from divorced families grew up to show a higher risk of premature mortality across the life span. The higher mortality risk for men was explained, in part, when 3 mediating factors were controlled: Men who had experienced parental divorce were more likely to have their own marriages end in divorce, obtained less education, and engaged in fewer service activities. Women who had experienced parental divorce smoked more and were more likely themselves to divorce, both of which predicted higher mortality risk. The findings extend previous work on the negative sequelae of parental divorce to long-term effects on personality and longevity.

Adolescent

The epidemiology of peripheral arterial disease: importance of identifying the population at risk.

Data from the Framingham Study and other population studies indicate that intermittent claudication (IC) sharply increases in late middle age and is somewhat higher among men than women. Noninvasive testing in populations indicates that the true prevalence of peripheral arterial disease (PAD) is at least five times higher than would be expected based on the reported prevalence of IC. Peripheral arterial disease correlates most strongly with cigarette smoking and either diabetes or impaired glucose tolerance. Other risk factors for PAD include hypertension; low levels of high-density lipoprotein cholesterol; and high levels of triglycerides, apolipoprotein B, lipoprotein(a), homocysteine, fibrinogen and blood viscosity. Individuals with PAD are more likely to have coronary heart disease and cerebrovascular disease than those without PAD. Because of the high risk of both nonfatal and fatal cardiovascular disease (CVD) events in PAD patients, individuals with evidence of PAD should undergo both a careful examination of the entire cardiovascular system and aggressive modification of CVD risk factors.

Adult

A randomized trial of cardiovascular risk factor reduction: patterns of attrition after randomization and during follow-up.

BACKGROUND: The Preventive Cardiology Center compared two intensities of behavior modification for cardiovascular disease (CVD) risk factors in persons at risk and their families. Characteristics of drop-outs both before and after intervention were compared with subjects who completed the 6-month trial. METHODS: A total of 333 individuals of all ages were enrolled in the study and randomly assigned by family to a single-session ('skills' group-low-intensity) or a five-session ('practice' group-high intensity) intervention. Baseline and follow-up assessments included a personal and family health questionnaire, nutritional intake survey, and clinic visit to obtain blood pressure, lipids, and height and weight data. RESULTS: Two hundred and forty adults over 18 years of age were randomly assigned to one of the two intervention groups. Of these, 68 subjects (28.3%) did not participate in the intervention. Multivariate analysis revealed that these 'early drop-outs' were significantly more likely to be non-white and to have had a lower LDL cholesterol. Of the 172 subjects attending the intervention, 70 (40.7%) did not attend the 6-month follow-up ('late drop-outs'). Multivariate analysis revealed that, compared with follow-up attendees, non-attendees were significantly more likely to be white and to be current smokers. CONCLUSIONS: Both early and late drop-outs in a randomized trial of CVD risk reduction were significantly different than continuing participants in several key factors. These differences suggest the use of caution in both interpreting and making generalizations about behavioral trials of risk factor reduction when attrition is high.

Adolescent

Alcohol and coronary heart disease: consistent relationship and public health implications.

The relationship between alcohol consumption and coronary heart disease (CHD) in various epidemiologic study designs is consistent, showing protection at < or = 2 drinks per day, with an increase in risk of CHD in several studies at higher alcohol consumption levels. Studies of potential mediators of the effects of alcohol on CHD show beneficial effects on HDL cholesterol and some coagulation factors, but, at higher levels of consumption, adverse effects on blood pressure, arrhythmias, and the myocardium. Statistical modeling of pathways for alcohol's effect on coronary disease is consistent with a protective pathway via elevated HDL cholesterol and an adverse pathway through elevated blood pressure. Maximum benefit for CHD appears to be reached at only one drink daily. Given that alcohol is an intoxicating and potentially addictive substance with a high abuse potential, and given the high morbidity and mortality associated with heavier drinking, public health recommendations to consume alcohol are contraindicated.

Alcohol Drinking