Development and validation of an ankle brachial index risk model for the prediction of cardiovascular events

BACKGROUND

The ankle brachial index (ABI) is related to risk of cardiovascular events independent of the Framingham risk score (FRS). The aim of this study was to develop and evaluate a risk model for cardiovascular events incorporating the ABI and FRS.

DESIGN

An analysis of participant data from 18 cohorts in which 24,375 men and 20,377 women free of coronary heart disease had ABI measured and were followed up for events.

METHODS

Subjects were divided into a development and internal validation dataset and an external validation dataset. Two models, comprising FRS and FRS + ABI, were fitted for the primary outcome of major coronary events.

RESULTS

In predicting events in the external validation dataset, C-index for the FRS was 0.672 (95% CI 0.599 to 0.737) in men and 0.578 (95% CI 0.492 to 0.661) in women. The FRS + ABI led to a small increase in C-index in men to 0.685 (95% CI 0.612 to 0.749) and large increase in women to 0.690 (95% CI 0.605 to 0.764) with net reclassification improvement (NRI) of 4.3% (95% CI 0.0 to 7.6%, p = 0.050) and 9.6% (95% CI 6.1 to 16.4%, p < 0.001), respectively. Restricting the FRS + ABI model to those with FRS intermediate 10-year risk of 10 to 19% resulted in higher NRI of 15.9% (95% CI 6.1 to 20.6%, p < 0.001) in men and 23.3% (95% CI 13.8 to 62.5%, p = 0.002) in women. However, incorporating ABI in an improved newly fitted risk factor model had a nonsignificant effect: NRI 2.0% (95% CI 2.3 to 4.2%, p = 0.567) in men and 1.1% (95% CI 1.9 to 4.0%, p = 0.483) in women.

CONCLUSIONS

An ABI risk model may improve prediction especially in individuals at intermediate risk and when performance of the base risk factor model is modest.

The relationship between sex hormones, sex hormone binding globulin and peripheral artery disease in older persons

OBJECTIVE

The prevalence of peripheral artery disease (PAD) increases with aging and is higher in persons with metabolic syndrome and diabetes. PAD is associated with adverse outcomes, including frailty and disability. The protective effect of testosterone and sex hormone binding globulin (SHBG) for diabetes in men suggests that the biological activity of sex hormones may affect PAD, especially in older populations.

METHODS

Nine hundred and twenty-one elderly subjects with data on SHBG, testosterone (T), estradiol (E2) were selected from InCHIANTI study. PAD was defined as an Ankle-Brachial Index (ABI) < 0.90. Logistic regression models adjusted for age (Model 1), age, BMI, insulin, interleukin-6, physical activity, smoking, chronic diseases including metabolic syndrome (Model 2), and a final model including also sex hormones (Model 3) were performed to test the relationship between SHBG, sex hormones and PAD.

RESULTS

The mean age (±SD) of the 419 men and 502 women was 75.0 ± 6.8 years. Sixty two participants (41 men, 21 women) had ABI < 0.90. Men with PAD had SHBG levels lower than men without PAD (p = 0.03). SHBG was negatively and independently associated with PAD in men (p = 0.028) but not in women. The relationship was however attenuated after adjusting for sex hormones (p = 0.07). The E2 was not significantly associated with PAD in both men and women. In women, but not in men, T was positively associated with PAD, even after adjusting for multiple confounders, including E2 (p = 0.01).

CONCLUSIONS

Low SHBG and high T levels are significantly and independently associated with the presence of PAD in older men and women, respectively.

Ankle brachial index combined with Framingham Risk Score to predict cardiovascular events and mortality: a meta-analysis

CONTEXT

Prediction models to identify healthy individuals at high risk of cardiovascular disease have limited accuracy. A low ankle brachial index (ABI) is an indicator of atherosclerosis and has the potential to improve prediction.

OBJECTIVE

To determine if the ABI provides information on the risk of cardiovascular events and mortality independently of the Framingham risk score (FRS) and can improve risk prediction.

DATA SOURCES

Relevant studies were identified. A search of MEDLINE (1950 to February 2008) and EMBASE (1980 to February 2008) was conducted using common text words for the term ankle brachial index combined with text words and Medical Subject Headings to capture prospective cohort designs. Review of reference lists and conference proceedings, and correspondence with experts was conducted to identify additional published and unpublished studies.

STUDY SELECTION

Studies were included if participants were derived from a general population, ABI was measured at baseline, and individuals were followed up to detect total and cardiovascular mortality.

DATA EXTRACTION

Prespecified data on individuals in each selected study were extracted into a combined data set and an individual participant data meta-analysis was conducted on individuals who had no previous history of coronary heart disease.

RESULTS

Sixteen population cohort studies fulfilling the inclusion criteria were included. During 480,325 person-years of follow-up of 24,955 men and 23,339 women, the risk of death by ABI had a reverse J-shaped distribution with a normal (low risk) ABI of 1.11 to 1.40. The 10-year cardiovascular mortality in men with a low ABI (< or = 0.90) was 18.7% (95% confidence interval [CI], 13.3%-24.1%) and with normal ABI (1.11-1.40) was 4.4% (95% CI, 3.2%-5.7%) (hazard ratio [HR], 4.2; 95% CI, 3.3-5.4). Corresponding mortalities in women were 12.6% (95% CI, 6.2%-19.0%) and 4.1% (95% CI, 2.2%-6.1%) (HR, 3.5; 95% CI, 2.4-5.1). The HRs remained elevated after adjusting for FRS (2.9 [95% CI, 2.3-3.7] for men vs 3.0 [95% CI, 2.0-4.4] for women). A low ABI (< or = 0.90) was associated with approximately twice the 10-year total mortality, cardiovascular mortality, and major coronary event rate compared with the overall rate in each FRS category. Inclusion of the ABI in cardiovascular risk stratification using the FRS would result in reclassification of the risk category and modification of treatment recommendations in approximately 19% of men and 36% of women.

CONCLUSION

Measurement of the ABI may improve the accuracy of cardiovascular risk prediction beyond the FRS.

Peripheral arterial disease and depressed mood in older men and women

The objective of this study was to determine whether lower extremity peripheral arterial disease (PAD) is associated with depressive symptoms and whether PAD-related disability mediates the association between PAD and depressive symptoms. The study used a cross-sectional design set in an academic medical center. A cohort of men and women aged 55 years and older with (n = 93) or without (n = 74) PAD was recruited. PAD subjects were identified from a blood flow laboratory and a general medicine practice. Non-PAD subjects were identified from the same general medicine practice. PAD was diagnosed and quantified using the ankle-brachial index (ABI). Depressive symptoms were assessed by the 15-item short version of the Geriatric Depression Scale (GDS-S; score range 0-15, 0 = no depressive symptoms). The six-minute walk test and the Walking Impairment Questionnaire (WIQ) distance score (score range 0-100, 100 = better walking ability) were measures of walking impairment. PAD subjects had depressive mood (DM) (defined by GDS-S score >5) twice as often as controls (24% vs 12%, p = 0.06). After adjustment for age, education, and number of comorbidities, the prevalence of depressive mood among PAD subjects was increased, but this association was not significant (OR = 1.8, 95% CI 0.7-4.4). The WIQ distance score weakened the association between PAD and DM, and higher distance scores were associated with a lower likelihood of DM (OR = 0.98 per one unit of the WIQ, 95% CI 0.96-0.99). Among PAD subjects, severe PAD (ABI <0.5) was not significantly associated with DM (OR = 1.4, 95% CI 0.5-4.1), but a greater 6-min walk distance was associated with a lower likelihood of DM (OR = 0.8 per 100 feet, 95% CI 0.70-0.97). Substituting the WIQ scores for six-min walk distance in the model showed that higher WIQ scores were associated with lower likelihood of DM among PAD subjects (OR= 0.98 per one unit of the WIQ, 95% CI 0.95-1.0), though the association did not achieve statistical significance. In conclusion, these data suggest that PAD may be associated with an increased risk of DM and that this relationship may be related to PAD-associated disability. An evaluation for depression may be appropriate in men and women with PAD. Findings should be evaluated in a larger study cohort.

Leg symptoms in peripheral arterial disease: associated clinical characteristics and functional impairment

CONTEXT

Persons with lower-extremity peripheral arterial disease (PAD) are often asymptomatic or have leg symptoms other than intermittent claudication (IC).

OBJECTIVE

To identify clinical characteristics and functional limitations associated with a broad range of leg symptoms identified among patients with PAD.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study of 460 men and women with PAD and 130 without PAD, who were identified consecutively, conducted between October 1998 and January 2000 at 3 Chicago-area medical centers.

MAIN OUTCOME MEASURES

Ankle-brachial index score of less than 0.90; scores from 6-minute walk, accelerometer-measured physical activity over 7 days, repeated chair raises, standing balance (full tandem stand), 4-m walking velocity, San Diego claudication questionnaire, Geriatric Depression Score Short-Form, and the Walking Impairment Questionnaire.

RESULTS

All groups with PAD had poorer functioning than participants without PAD. The following values are for patients without IC vs those with IC. Participants in the group with leg pain on exertion and rest (n = 88) had a higher (poorer) score for neuropathy (5.6 vs 3.5; P<.001), prevalence of diabetes mellitus (48.9% vs 26.7%; P<.001), and spinal stenosis (20.8% vs 7.2%; P =.002). The atypical exertional leg pain/carry on group (exertional leg pain other than IC associated with walking through leg pain [n = 41]) and the atypical exertional leg pain/stop group (exertional leg pain other than IC that causes one to stop walking [n = 90]) had better functioning than the IC group. The group without exertional leg pain/inactive (no exertional leg pain in individual who walks </=6 blocks per week [n = 28]) and the leg pain on exertion and rest group had poorer functioning than those with IC. Adjusting for age, sex, race, and comorbidities and compared with IC, participants with atypical exertional leg pain/carry on achieved a greater distance on the 6-minute walk (404.3 vs 328.5 m; P<.001) and were less likely to stop during the 6-minute walk (6.8% vs 36%; P =.002). The group with pain on exertion and rest had a slower time for completing 5 chair raises (13.5 vs 11.9 seconds; P =.009), completed the tandem stand less frequently (37.5% vs 60.0%; P =.004), and had a slower 4-m walking velocity (0.80 vs 0.90 m/s; P<.001).

CONCLUSIONS

There is a wide range of leg symptoms in persons with PAD beyond that of classic IC. Comorbid disease may contribute to these symptoms in PAD. Functional impairments are found in every PAD symptom group, and the degree of functional limitation varies depending on the type of leg symptom.

Peripheral arterial disease detection, awareness, and treatment in primary care

CONTEXT

Peripheral arterial disease (PAD) is a manifestation of systemic atherosclerosis that is common and is associated with an increased risk of death and ischemic events, yet may be underdiagnosed in primary care practice.

OBJECTIVE

To assess the feasibility of detecting PAD in primary care clinics, patient and physician awareness of PAD, and intensity of risk factor treatment and use of antiplatelet therapies in primary care clinics.

DESIGN AND SETTING

The PAD Awareness, Risk, and Treatment: New Resources for Survival (PARTNERS) program, a multicenter, cross-sectional study conducted at 27 sites in 25 cities and 350 primary care practices throughout the United States in June-October 1999.

PATIENTS

A total of 6979 patients aged 70 years or older or aged 50 through 69 years with history of cigarette smoking or diabetes were evaluated by history and by measurement of the ankle-brachial index (ABI). PAD was considered present if the ABI was 0.90 or less, if it was documented in the medical record, or if there was a history of limb revascularization. Cardiovascular disease (CVD) was defined as a history of atherosclerotic coronary, cerebral, or abdominal aortic aneurysmal disease.

MAIN OUTCOME MEASURES

Frequency of detection of PAD; physician and patient awareness of PAD diagnosis; treatment intensity in PAD patients compared with treatment of other forms of CVD and with patients without clinical evidence of atherosclerosis.

RESULTS

PAD was detected in 1865 patients (29%); 825 of these (44%) had PAD only, without evidence of CVD. Overall, 13% had PAD only, 16% had PAD and CVD, 24% had CVD only, and 47% had neither PAD nor CVD (the reference group). There were 457 patients (55%) with newly diagnosed PAD only and 366 (35%) with PAD and CVD who were newly diagnosed during the survey. Eighty-three percent of patients with prior PAD were aware of their diagnosis, but only 49% of physicians were aware of this diagnosis. Among patients with PAD, classic claudication was distinctly uncommon (11%). Patients with PAD had similar atherosclerosis risk factor profiles compared with those who had CVD. Smoking behavior was more frequently treated in patients with new (53%) and prior PAD (51%) only than in those with CVD only (35%; P <.001). Hypertension was treated less frequently in new (84%) and prior PAD (88%) only vs CVD only (95%; P <.001) and hyperlipidemia was treated less frequently in new (44%) and prior PAD (56%) only vs CVD only (73%, P<.001). Antiplatelet medications were prescribed less often in patients with new (33%) and prior PAD (54%) only vs CVD only (71%, P<.001). Treatment intensity for diabetes and use of hormone replacement therapy in women were similar across all groups.

CONCLUSIONS

Prevalence of PAD in primary care practices is high, yet physician awareness of the PAD diagnosis is relatively low. A simple ABI measurement identified a large number of patients with previously unrecognized PAD. Atherosclerosis risk factors were very prevalent in PAD patients, but these patients received less intensive treatment for lipid disorders and hypertension and were prescribed antiplatelet therapy less frequently than were patients with CVD. These results demonstrate that underdiagnosis of PAD in primary care practice may be a barrier to effective secondary prevention of the high ischemic cardiovascular risk associated with PAD.

Prevalence and significance of unrecognized lower extremity peripheral arterial disease in general medicine practice*

OBJECTIVE

To determine the prevalence of unrecognized lower extremity peripheral arterial disease (PAD) among men and women aged 55 years and older in a general internal medicine (GIM) practice and to identify characteristics and functional performance associated with unrecognized PAD.

DESIGN

Cross-sectional.

SETTING

Academic medical center.

PARTICIPANTS

We identified 143 patients with known PAD from the noninvasive vascular laboratory, and 239 men and women aged 55 and older with no prior PAD history from a GIM practice. Group 1 consisted of patients with PAD consecutively identified from the noninvasive vascular laboratory (n = 143). Group 2 included GIM practice patients found to have an ankle brachial index less than 0.90, consistent with PAD (n = 34). Group 3 consisted of GIM practice patients without PAD (n = 205).

MEASUREMENTS AND MAIN RESULTS

Leg functioning was assessed with the 6-minute walk, 4-meter walking velocity, and Walking Impairment Questionnaire (WIQ). Of GIM practice patients, 14% had unrecognized PAD. Only 44% of patients in Group 2 had exertional leg symptoms. Distances achieved in the 6-minute walk were 1,130, 1,362, and 1,539 feet for Groups 1, 2, and 3, respectively, adjusting for age, gender, and race (P <.001). The degree of difficulty walking due to leg symptoms as reported on the WIQ was comparable between Groups 2 and 3 and significantly greater in Group 1 than Group 2. In multiple logistic regression analysis including Groups 2 and 3, current cigarette smoking was associated independently with unrecognized PAD (odds ratio [OR], 6.82; 95% confidence interval [95% CI], 1.55 to 29.93). Aspirin therapy was nearly independently associated with absence of PAD (OR, 0.37; 95% CI, 0.12 to 1.12).

CONCLUSION

Unrecognized PAD is common among men and women aged 55 years and older in GIM practice and is associated with impaired lower extremity functioning. Ankle brachial index screening may be necessary to diagnose unrecognized PAD in a GIM practice.

Gait alterations associated with walking impairment in people with peripheral arterial disease with and without intermittent claudication

OBJECTIVES

To describe gait alterations associated with impaired walking endurance in patients with and without lower-extremity peripheral arterial disease (PAD) and determine whether the Caltrac accelerometer provides a valid measure of physical activity in PAD.

DESIGN

Cross-sectional.

SETTING

Academic medical center.

PARTICIPANTS

PAD (n = 40) and non-PAD patients (n = 22) from two Chicago hospitals.

MEASUREMENTS

Participants underwent measurement of the ankle brachial index (ABI), leg length, and 6-minute walk. Steps per minute and step length were measured during the first and last 100 feet of the 6-minute walk. Participants wore a Caltrac accelerometer, sensitive to vertical acceleration, during the 6-minute walk and for 7 continuous days.

RESULTS

Five PAD participants (13%) and one non-PAD participant (5%) ceased walking before the end of 6 minutes. Among the remaining participants, distance walked in 6 minutes was more highly related to walking velocity during the last 100 feet of the walk than walking velocity during the first 100 feet. ABI was associated significantly with cadence (20.77 steps/minute per unit ABI, P <.001) but not step length (10.12 centimeters/unit ABI, P =.08). ABI was associated significantly with 6-minute walk distance (493 feet/unit ABI, P =.018), but this association disappeared completely after adjustment for step length and cadence. We found no difference in accelerometer scores between PAD and non-PAD participants over a fixed distance of 800 feet (7.34 vs 7.17 activity units, P =.789). However, scores were significantly different after 7 days (730.8 vs 1,485.0 activity units, P =.003).

CONCLUSION

Walking performance in PAD patients who completed 6 minutes of walking was largely determined by a decline in walking velocity rather than slower initial walking velocity. ABI was more closely associated with cadence than step length. Future studies should assess the effect of exercise programs and revascularization on cadence and step length in PAD.

Lower ankle/brachial index, as calculated by averaging the dorsalis pedis and posterior tibial arterial pressures, and association with leg functioning in peripheral arterial disease

OBJECTIVE

We compared three commonly used methods of ankle/brachial index (ABI) calculation to determine their relative association with objective measures of leg functioning in peripheral arterial disease.

METHOD

The study design was cross-sectional; the setting was an academic medical center. The participants were 244 men and women, aged 55 years and older, with and without peripheral arterial disease, from a noninvasive vascular laboratory and a general medicine practice. The main outcome measures were walking velocity and endurance, measured with the 4-m walk and the 6-minute walk, respectively. Three methods of ABI calculation were assessed: using the highest arterial pressure within each leg (method #1), using the lowest pressure in each leg (method #2), and averaging the dorsalis pedis and posterior tibial pressures within each leg (method #3). For each method, we established the prevalence of peripheral arterial disease. We then used regression analyses to identify the ABI calculation method most closely associated with leg functioning. The ABI with the greatest statistical significance and largest regression coefficient was considered most closely associated with leg functioning.

RESULTS

Peripheral arterial disease prevalence ranged from 47% when method #1 was used to 59% when method #2 was used. When the right and left legs were compared, the leg with the lower ABI, as identified through use of method #3, was most associated with leg functioning. Within the leg with the lower ABI, method #3 was more closely associated with 6-minute walk distance (regression coefficient = 811.5 feet per 1 unit ABI; P<.001) and 4-m walking velocity (regression coefficient = 0.353 m/s per 1 unit ABI; P<.001) than method #1 or method #2.

CONCLUSION

The lower ABI, determined by averaging the dorsalis pedis and posterior tibial arterial pressures in each leg, is most predictive of walking endurance and walking velocity in peripheral arterial disease.

Asymptomatic peripheral arterial disease is independently associated with impaired lower extremity functioning: the women's health and aging study

BACKGROUND

We report the implications of asymptomatic lower extremity peripheral arterial disease (PAD) for lower extremity functioning among participants in the Women's Health and Aging Study, an observational study of disabled women > or = 65 years of age living in and around Baltimore.

METHODS AND RESULTS

The ankle brachial index (ABI) and measures of upper and lower extremity functioning were measured among study participants. Of 933 women with ABI < or =1. 50, 328 (31%) [corrected] had an ABI <0.90, consistent with PAD. Sixty-three percent of PAD participants had no exertional leg pain. Among participants without exertional leg pain, lower ABI levels were associated with slower walking velocity, poorer standing balance score, slower time to arise 5 times consecutively from a seated position, and fewer blocks walked per week, adjusting for age, sex, race, cigarette smoking, and comorbidities. ABI was not associated independently with measures of upper extremity functioning.

CONCLUSIONS

Asymptomatic PAD is common and is independently associated with impaired lower extremity functioning. In addition to preventing cardiovascular morbidity and death, further study is warranted to identify effective interventions to improve functioning among the growing number of men and women with asymptomatic PAD.

Measuring physical activity in peripheral arterial disease: a comparison of two physical activity questionnaires with an accelerometer

Peripheral arterial disease (PAD)-related exertional leg pain may limit physical activity, thereby contributing to mobility loss and increasing cardiovascular morbidity and mortality in men and women with PAD. The objectives of this study were: (1) to compare objectively measured physical activity levels between patients with and without PAD, (2) to assess the validity of two physical activity questionnaires in patients with PAD. Twenty PAD patients from a noninvasive vascular laboratory and 21 patients without PAD from a general medicine practice wore an accelerometer continuously for 7 days to measure physical activity objectively. After 7 days, participants completed the leisure time physical activity questionnaire (LTPAQ), derived from the Health Interview Survey, (continued on next page)and the Stanford 7-day physical activity recall questionnaire (PARQ). PAD participants had markedly lower physical activity levels than non-PAD participants as measured by accelerometer (803 kcal/week +/-364 (range=284-2,000, median=708) vs 1,750 kcal/week +/-1,296 (range=882-6,586, median=1,278), p<0.001). For the LTPAQ, physical activity levels in PAD and non-PAD participants were 609 kcal/week +/-576 (range=0-2,085, median=529) vs 832 kcal/week +/-784 (range=53-2,820, median= 623), p=0.128. For the PARQ, physical activity levels in PAD and non-PAD participants were 234 METS/week +/-21 (range=214-301, median=229) vs 238 METS/week +/- 11 (range=225-268, median=234), p=0.454, respectively. Pearson's correlation coefficient for the association between the accelerometer and the log-transformed LTPAQ measure was 0.419 (p=0.006). Pearson's correlation coefficient was 0.348 for the association between the accelerometer and the log-transformed PARQ measure of physical activity (p=0.026). In conclusion, PAD patients have significantly lower physical activity levels than non-PAD patients. Two commonly used physical activity questionnaires were less sensitive than objective measurement to the association between PAD and inactivity.

Use of learning contracts in an office-based primary care clerkship

OBJECTIVES

This paper describes implementation of the learner-centred learning goal within the primary care clerkship at a Midwestern, United States medical school.

DESIGN

The learner-centred learning goal exercise was developed to tailor students' educational activities to their personal level of development and to enhance their commitment to life-long learning in medicine. In the learner-centred learning goal exercise, each student records three specific learning goals early in the primary care clerkship. Students record the methods by which they will pursue and document achievement of each goal. Attainment of the learner-centred learning goal is evaluated based on an oral presentation at the end of the clerkship. We compiled presented learning goals along with the corresponding grade. Students' ratings of the learner-centred learning goal exercise were also compiled. Evaluations and ratings were made on a 1-5 Likert scale, where 1 is the best rating and 5 is worst.

SETTING

Department of Medicine, Northwestern University Medical School, Chicago, USA.

SUBJECTS

One hundred and seventy-seven third- and fourth-year medical students who presented learner-centred learning goals between 1 July 1995 and 30 June 1996.

RESULTS

Students rated pursuing their individual learning goals more worthwhile than most clerkship lectures but less worthwhile than the office experience. Several learning goals were chosen by a disproportionate number of students, potentially indicative of some perceived deficiencies elsewhere in the curriculum. Third-year students ranked the learner-centred learning goal exercise more favourably than fourth-year students (2.14 vs. 2. 51, P = 0.03).

CONCLUSIONS

The learner-centred learning goal exercise is a feasible and well-received method within our primary care clerkship. Further study is required to determine whether the exercise promotes independent learning after formal medical school education is completed.

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.

Impact of same-day screening mammography availability: results of a controlled clinical trial

BACKGROUND

We conducted a prospective controlled clinical trial in an urban academic general medicine practice to test the effect of same-day mammography availability on adherence to physicians' screening mammography recommendations.

PATIENTS AND METHODS

Participants were a consecutive sample of 920 female patients aged 50 years or older who had received a physician's recommendation for screening mammography at an office visit and had no active breast symptoms, history of breast cancer, or a mammogram within the previous 12 months. Women were assigned to same-day screening mammography availability (intervention group) or usual screening mammography scheduling (control group).

MAIN OUTCOME MEASURES

Three-, 6-, and 12-month rates of adherence to physicians' recommendations for screening mammography.

RESULT

Twenty-six percent of women in the intervention group obtained a same-day screening mammogram. At 3 months, 58% of the women in the intervention group underwent the recommended screening mammography compared with 43% of the women in the control group (P<.001), increasing to 61% and 49% at 6 months (P<.001), and 268 (66%) of 408 vs 287 (56%) of 512 at 12 months (P = .003). The difference between the intervention and control groups 3-month adherence rates was most marked among women aged 65 years or older (58% vs 34%; P<.001), women who were not employed (54% vs 36%; P<.001), and women with a history of having had either no mammograms (39% vs 20%; P = .02) or only 1 to 2 mammograms (57% vs 38%; P<.001) within the last 5 years.

CONCLUSIONS

Same-day mammography availability increased 3-, 6-, and 12-month screening mammography adherence rates in this urban academic general medicine practice. The effect was most marked among women aged 65 years or older, women who were not employed, and those who had had fewer than 3 mammograms in the last 5 years. The efficacy of this intervention in other settings still needs to be demonstrated.

Exertional leg symptoms other than intermittent claudication are common in peripheral arterial disease

BACKGROUND

Epidemiological data show that most community-dwelling men and women with lower-extremity peripheral arterial disease (PAD) do not have typical symptoms of intermittent claudication. We compared the prevalence of intermittent claudication, leg symptoms other than intermittent claudication, and absence of exertional leg symptoms between patients with PAD identified from a blood flow laboratory (group 1), patients with PAD in a general medicine practice (group 2), and control patients without PAD (group 3).

METHODS

Numbers of participants in groups 1, 2, and 3 were 137, 26, and 105, respectively. Patients with previously diagnosed PAD were excluded from groups 2 and 3. All participants underwent ankle-brachial index measurement and were administered the San Diego claudication questionnaire to assess leg symptoms.

RESULTS

Within groups 1, 2, and 3, prevalences of intermittent claudication were 28.5% (n = 39), 3.8% (n = 1), and 3.8% (n= 4), respectively. Prevalences of exertional leg symptoms other than intermittent claudication were 56.2% (n= 77), 42.3% (n= 11), and 19.0% (n = 20), respectively. Absence of exertional leg symptoms was reported by 15.3% (n= 21), 53.8% (n= 14), and 77.1% (n=81), respectively. Among patients with PAD, older age, male sex, diabetes mellitus, and group 2 vs group 1 status were associated independently with absence of exertional leg symptoms in multivariable regression analysis. Lower ankle-brachial index levels and group 1 vs group 2 status were associated with intermittent claudication.

CONCLUSIONS

Clinical manifestations of PAD are diverse, particularly among patients identified by ankle-brachial index screening. Exertional leg symptoms other than intermittent claudication are common in PAD. Patients with PAD who are older, male, diabetic, or identified with ankle-brachial index screening in a primary care setting are more likely to have asymptomatic PAD.

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.

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.

Patterns of angiotensin-converting enzyme inhibitor prescriptions, educational interventions, and outcomes among hospitalized patients with heart failure

BACKGROUND

Among hospitalized patients with heart failure, we describe characteristics associated with prescription of angiotensin-converting enzyme (ACE) inhibitors in the doses recommended by clinical practice guidelines. We also describe the impact of ACE inhibitor prescriptions, increases in ACE inhibitor dose, and nonpharmacologic educational interventions on readmission-free survival rates.

HYPOTHESIS

We hypothesize that care by a cardiologist physician and higher mean arterial blood pressure on admission are associated with receipt of optimal ACE inhibitor doses. We hypothesize that receipt of an ACE inhibitor at discharge and an increase in ACE inhibitor dose during hospitalization are associated with superior readmission-free survival.

METHODS

Between January 1, 1992, and December 31, 1993, medical records were reviewed for consecutively hospitalized patients with a principal diagnosis of heart failure at an academic medical center. Documented instructions and medications prescribed at discharge were abstracted. Deaths and readmissions through December 31, 1994, were identified with the National Death Index and the study institution's administrative data base, respectively.

RESULTS

During 1992 and 1993, 387 patients were discharged alive from hospitalization for heart failure. Among patients discharged on enalapril or captopril, 18% received doses recommended by heart failure clinical practice guidelines. Patients discharged on a recommended ACE inhibitor dose were more likely to be African-American and had lower sodium levels and higher mean arterial pressures than patients discharged on lower ACE inhibitor doses. In survival analyses, an increase in ACE inhibitor dose was associated with improved readmission-free survival, independent of left ventricular systolic function type. Receipt of an ACE inhibitor at discharge was also associated with superior readmission-free survival, while nonpharmacologic educational instructions were not associated with improved outcomes.

CONCLUSION

Interventions are needed to improve the frequency with which ACE inhibitors are prescribed at recommended doses to hospitalized patients with heart failure. We conclude that among these patients, receipt of an ACE inhibitor at discharge and an increase in ACE inhibitor dose during hospitalization are each associated with measurable effects on readmission-free survival, while provision of educational instructions as currently practiced is not associated with better outcomes.

Heart failure between 1986 and 1994: temporal trends in drug-prescribing practices, hospital readmissions, and survival at an academic medical center

Since 1987, publications in widely circulated medical journals have reported improved survival and lower hospital readmission rates when patients with heart failure and systolic dysfunction are treated with angiotensin-converting enzyme (ACE) inhibitors. We describe changes in ACE inhibitor use among patients hospitalized with heart failure between 1986 and 1993. Simultaneous trends in readmissions and survival rates are reported. Subjects were 612 consecutive patients hospitalized with a principal diagnosis of heart failure at an academic medical center during the period of Sept. 1, 1986, to Dec. 31, 1987 (interval I) or during the period Aug. 1, 1992, to Nov. 30, 1993 (interval II). Medical records were reviewed for 434 patients, consisting of all patients hospitalized with heart failure during interval II and a randomly selected 50% subset of patients hospitalized during interval I. Among 145 patients with systolic dysfunction whose medical records were reviewed, ACE inhibitor prescriptions significantly increased between interval I and interval II (43% vs 71%, p < 0.01, odds ratio 3.22, 95% confidence interval 1.62 to 6.42). Prescriptions of ACE inhibitors combined with digoxin and a diuretic also increased (37% vs 56%, p = 0.02, odds ratio 2.22, 95% confidence interval 1.14 to 4.32). Among all 612 patients, 6-month heart failure readmission rates increased from 13% to 21% (p = 0.02, odds ratio 1.79, 95% confidence interval 1.10 to 2.82). There was no significant change in survival rate between interval I and interval II, however, survival rate was marginally significantly improved among patients with systolic dysfunction. Our results suggest that drug-prescribing practices have significantly changed between 1986 and 1993. The absence of observed improvement in outcomes may result from changes in hospital admission criteria for heart failure.

Systolic function, readmission rates, and survival among consecutively hospitalized patients with congestive heart failure

We sought to describe the relation between left ventricular systolic function and rates of hospital readmission and survival among consecutively hospitalized patients with congestive heart failure. Medical records were reviewed for these patients at an academic medical center between Jan. 1, 1992, and Dec. 31, 1993. Left ventricular systolic function assessments performed within 6 months before discharge were used to classify left ventricular systolic function. Hospital readmission rates and survival through Dec. 31, 1994, were compared between patients with systolic dysfunction and those with preserved systolic function. Among 412 patients hospitalized with a primary diagnosis of congestive heart failure, 224 had undergone a left ventricular function assessment during the 6 months before hospital discharge. In-hospital mortality and readmission rates were higher among patients without a recent assessment of left ventricular systolic function. Of patients with systolic dysfunction, 55% versus 41% of patients with preserved systolic function were either readmitted or had an emergency room visit within 6 months after discharge (p = 0.06). At 27 months' follow-up, cumulative survival probabilities were 65% for patients with preserved systolic function, 65% for patients with systolic dysfunction, and 60% for patients without a left ventricular systolic function assessment (p = 0.24). Patients without a recent left ventricular systolic function assessment have significantly higher hospital readmission rates than patients with a recent systolic function assessment. Among hospitalized patients, mortality rates are comparable between patients with systolic dysfunction and those with preserved systolic function. However, patients with heart failure with systolic dysfunction may have higher readmission rates.

Impact of medication nonadherence on coronary heart disease outcomes. A critical review

A critical review of published literature was performed to assess the impact of medication adherence on morbidity and mortality among patients with or at risk for coronary artery disease and congestive heart failure. Twenty-one original research articles that met our inclusion criteria and related medication adherence to morbidity and mortality are summarized. No clinical trials that specifically tested the impact of a compliance-enhancing intervention on outcome in coronary heart disease were identified. Among 12 studies that compared hospitalization rates and mortality between adherers and nonadherers, 7 showed a significant relationship between medication adherence and outcomes. Three studies showed that adherence to placebo was associated with improved outcomes, suggesting that adherent behavior may be a marker of better prognosis or confers a protective effect on patients with coronary heart disease. Further study is necessary to determine whether adherent behavior can be taught and whether compliance-enhancing strategies improve outcomes in coronary heart disease.

Age-related differences in breast carcinoma knowledge, beliefs, and perceived risk among women visiting an academic general medicine practice

BACKGROUND

This study assessed whether age-related differences in breast carcinoma knowledge and perceived risk exist among women in a primary care setting and whether these women's beliefs about the best age to begin screening mammography reflect those of their physicians.

METHODS

Consecutive women ages 30-70 years who visited an academic general medicine practice were asked to complete a questionnaire assessing breast carcinoma knowledge, beliefs, and perceived risk. Women's risk estimates were compared with individual risk probabilities derived from the Gail model. Women's beliefs about when to begin screening mammography were compared with the beliefs of the attending physicians in the practice. Questionnaire results were compared across age groups.

RESULTS

Six hundred seventy-four women completed the survey. Overall, knowledge scores were negatively correlated with age (correlation coefficient = -0.30, P = 0.001). The level of knowledge about the benefits of mammography was high across all age groups. In contrast, knowledge that breast carcinoma incidence increases with age was poor. Only 28% of all women recognized that breast carcinoma is more common among women age 65 years than among women age 40 years. Among all women, 26% underestimated their risk of developing breast carcinoma in the next 10 years, 32% correctly estimated their risk, and 42% overestimated their risk. Fifty-five percent thought that mammography should begin when a woman is age 30-35 years. In contrast, all surveyed physicians recommended that a woman start undergoing mammography at age 40 years or older.

CONCLUSIONS

In this primary care setting, older women had poorer breast carcinoma knowledge than younger women but were equally likely to appreciate the benefits of mammography. Most women were unaware that age is a risk factor for breast carcinoma. Improved education of females by their physicians may resolve some of the observed discrepancies regarding the optimal age to begin screening mammography.

Atherosclerotic risk factors are less intensively treated in patients with peripheral arterial disease than in patients with coronary artery disease

OBJECTIVE

To compare rates of therapy for atherosclerotic risk factors between patients with lower extremity peripheral arterial disease (PAD) and patients with coronary artery disease (CAD).

DESIGN

Cross-sectional.

SETTING

Academic medical center.

PATIENTS/PARTICIPANTS

Three hundred forty-nine consecutive patients diagnosed with PAD or CAD identified from the blood flow and cardiac catheterization laboratories, respectively.

MEASUREMENTS AND MAIN RESULTS

Participants were interviewed by telephone for medical history as well as therapies prescribed and recommended by their physicians. Among patients with hypercholesterolemia, more CAD patients were taking cholesterol-lowering drugs (58% vs 46%, p = .08) and more CAD patients recalled a physician's instruction to follow a low-fat, low-cholesterol diet (94% vs 83%, p = .01). CAD patients were more likely to exercise regularly (71% vs 50%, p < .01). Among patients not exercising, more CAD patients recalled a physician's advice to exercise (74% vs 47%, p < .01). In logistic regression analysis, hypercholesterolemic patients with exclusive CAD were more likely to be treated with drug therapy (odds ratio [OR] 2.3, p = .05). CAD patients were more likely to recall advice to exercise (OR 4.0, p < .001), and more likely to be taking aspirin or warfarin (OR 4.8, p = .01).

CONCLUSIONS

Atherosclerotic risk factors are less intensively treated among PAD patients than CAD patients. A number of possible explanations could account for these disparities in therapeutic intensity.

Effect of breast-tissue characteristics on the outcome of clinical breast examination training

PURPOSE

To compare the effects of clinical breast examination (CBE) training on lump-detection rates in simulated premenopausal and postmenopausal breast tissue.

METHOD

Two sets of six silicone models were made with background breast tissue simulating premenopausal tissue (most nodular, least soft) and postmenopausal breast tissue (least nodular, most soft) respectively. Eighteen lumps were located in each set of models. In September 1994, 82 housestaff and attending physicians with outpatient practices in the Division of General Internal Medicine at Northwestern University Medical School were randomized to a CBE-teaching intervention or a control group. Lump-detection rates for the two sets of models were measured before and after the teaching intervention. Analysis of covariance was used to analyze the effect of CBE training on examination sensitivity and specificity, controlling for baseline rates.

RESULTS

CBE training increased lump-detection rates similarly and significantly in models simulating premenopausal and postmenopausal tissue, respectively. Specificity declined after training in models simulating postmenopausal tissue (p = 0.02) but was unchanged in models simulating premenopausal tissue (p = 0.54). CBE training had greater influence on sensitivity among house-staff than among attending physicians (p = 0.02).

CONCLUSION

CBE training similarly affects lump detection in simulated premenopausal and postmenopausal breast tissue, but adversely affects specificity in simulated postmenopausal tissue only.

Lump detection is enhanced in silicone breast models simulating postmenopausal breast tissue

We varied the softness and nodularity of silicone breast models to assess the effects of age-related breast tissue characteristics on lump detection. In two sets of six silicone breast models manufactured to simulate premenopausal and postmenopausal breast tissue, respectively, 82 internal medicine attending and housestaff physicians more readily detected lumps among models simulating older breast tissue. The proportion of models with one or more false-positive findings was higher among models simulating postmenopausal breast tissue. We conclude that age-related changes in breast tissue most likely contribute to the higher sensitivity of clinical breast examination in older women.

Hospitalized congestive heart failure patients with preserved versus abnormal left ventricular systolic function: clinical characteristics and drug therapy

PURPOSE

To compare clinical characteristics of and pharmacologic therapy for hospitalized patients with congestive heart failure (CHF) and left ventricular systolic dysfunction or normal left ventricular systolic function.

PATIENTS AND METHODS

Medical records were reviewed for all patients discharged with a principal diagnosis of CHF from a university hospital and a community hospital between September 1, 1991 and August 31, 1992. Pertinent medical history items and prescribed drug therapies at discharge were recorded for each patient's first calendar year admission. Patients were categorized as having either normal left ventricular systolic function or systolic dysfunction based on the results of echocardiography and radionuclide angiography or contrast ventriculogram.

RESULTS

Of 298 patients with CHF, 92 (31%) had normal left ventricular systolic function. Patients with normal systolic function were older, were more often women, were less likely to have a history of coronary artery disease, and were more likely to have a history of hypothyroidism than patients with systolic dysfunction. However, the prevalence of clinical characteristics overlapped considerably between the two groups. Among patients with systolic dysfunction, 79% were discharged on a therapeutic regimen of digoxin, 65% on an angiotensin-converting enzyme inhibitor, and 26% on either a beta-blocker or a calcium channel blocker. Among patients with normal systolic function, 50% were discharged on a regimen of a beta-blocker or a calcium channel blocker and 38% were discharged on digoxin. Twenty-six percent of patients with normal systolic function and without a history of atrial fibrillation were discharged on a digoxin regimen.

CONCLUSION

Hospitalized CHF patients with normal left ventricular systolic function and those with diminished left ventricular systolic function share many clinical features. Since recommended drug therapy and prognosis differ, our data underscore the importance of diagnostic testing to assess left ventricular systolic function. Drug therapy for CHF patients provides a major challenge for quality-of-care improvement.

Intermittent claudication. The natural history

Intermittent claudication is a relatively common disorder, present in a subset of patients with lower extremity atherosclerotic disease. Although lower extremity morbidity rates are low, patients with claudication frequently have coexistent cardiovascular disease and are at significantly increased risk of adverse cardiovascular events. Data to support work-up for concomitant coronary artery disease in conservatively managed patients are not available; however, clinicians should consider the high prevalence of coronary artery disease when developing management strategies. Patients should be carefully selected for lower extremity interventional management given the generally benign lower extremity prognosis. Tobacco smokers should be urged to quit, owing to their higher rate of lower extremity and cardiovascular adverse outcomes. Functional outcomes after various treatment strategies have not yet been sufficiently studied in the claudicant.

Adherence to screening mammography recommendations in a university general medicine clinic

OBJECTIVE

To determine factors predicting adherence to a health care provider's screening mammography recommendation in a general internal medicine practice.

DESIGN

Prospective observational study.

SETTING

An urban academic general internal medicine practice.

PATIENTS

Three hundred forty-nine asymptomatic women, aged 50 years and older, without prior history of breast cancer, who received a health care provider's recommendation for screening mammography.

MEASUREMENT

Independent variables were: patient age, race, insurance type, educational level, and duration of affiliation with the practice; visit type; and health care provider gender and level of training. Dependent variables were acceptance of the recommendation and adherence, defined as undergoing mammography within three months of the recommendation.

RESULTS

Overall, 193 (55%) of the women underwent the recommended mammography. Two hundred ninety-eight (85%) initially agreed to the recommendation, and of these, 190 (64%) completed mammography within three months. By univariate analysis, acceptance of the recommendation decreased significantly with increasing age (p < 0.01), and by race (African-Americans 89% vs whites 82%, p = 0.05). Only age remained independently predictive of acceptance in a multiple variable analysis. Among women who accepted the recommendation, adherence varied significantly according to race (white 70% vs nonwhite 59%, p = 0.05), insurance type [Medicare as only insurance 45%, Medicaid 66%, non-health maintenance organization (non-HMO) private 62%, HMO 73%, p = 0.03], and health care provider training (attending physicians 73%, residents 58%, nurse practitioners 47%, p = 0.02). In a logistic regression analysis, insurance type and health care provider training remained independently predictive of adherence.

CONCLUSION

Acceptance of screening mammography recommendations decreases with age. Among the women who agreed to the recommendation for screening mammography, insurance type and health care provider level of training best predicted adherence.

Changes in study design, gender issues, and other characteristics of clinical research published in three major medical journals from 1971 to 1991

OBJECTIVE

To examine trends in study design and other characteristics of original research published in JAMA, Lancet, and the New England Journal of Medicine (NEJM) between 1971 and 1991.

DESIGN

A retrospective cross-sectional study of original clinical research published in JAMA, Lancet, and NEJM during 1971, 1981, and 1991.

MEASUREMENTS

Four hundred forty-four articles were independently reviewed by at least two investigators and classified according to study design and other preselected study characteristics. Changes over time were analyzed by chi-square tests for categorical variables and analysis of variance for continuous variables.

MAIN RESULTS

Clinical results doubled, from 17% of all articles in 1971 to 35% in 1991 (p < 0.004), while case series decreased from 30% to 4% (p < 0.0001). Of 118 clinical trials, randomized controlled trials increased from 31% to 76% (p < 0.003) and nonrandomized controlled trials decreased from 42% to 8% (p < 0.002). Multicenter studies increased from 10% to 39% (p < 0.0001) and the prevalence of health services research increased from none in 1971 to 12% in 1991 (p < 0.001). The proportion of the studies explicitly excluding women from the subject population decreased from 11% in 1971 to 3% in 1991 (p < 0.03). In 1991 7% of the studies were composed entirely of men subjects, while only 0.7% of the studies were specific to men's health. Twelve percent of the studies in 1991 were specific to women's health. Between 1971 and 1991 there was no change in the prevalence of women first authors or studies addressing women's or minorities' health issues.

CONCLUSIONS

Several important changes in clinical research studies published in JAMA, Lancet, and NEJM have taken place between 1971 and 1991. Clinical trials have increased in frequency, largely replacing studies containing ten or fewer subjects. Health services research has increased in prevalence, reflecting growing interest in studies addressing the delivery of health care. Our data support the hypothesis that exclusion of women from clinical research studies is an important contributor to the paucity of data concerning women's health.

ST segment depression detected by continuous electrocardiography in patients with acute ischemic stroke or transient ischemic attack

BACKGROUND AND PURPOSE

Forty percent of patients with a history of ischemic stroke or transient ischemic attack (TIA) have concomitant coronary artery disease. ST segment depression, detected by continuous electrocardiography, is associated with increased cardiac morbidity and mortality in patients with known coronary artery disease. While electrocardiographic changes have been associated with acute stroke, the etiology and significance of these changes remain unclear. In this pilot study we report the prevalence of ST segment depression and ventricular arrhythmias in patients with acute ischemic stroke or TIA monitored by continuous electrocardiography. Clinical predictors of ST segment depression and ventricular arrhythmia are also identified.

METHODS

Consecutive patients presenting with acute ischemic stroke or TIA were enrolled within 72 hours of hospital admission and monitored by continuous electrocardiography for 48 hours. The electrocardiographic results were analyzed for periods of ST segment depression and ventricular arrhythmias.

RESULTS

Of 51 patients with ischemic stroke or TIA, 15 (29%) had episodes of ST segment depression (95% confidence interval, 15% to 43%), and 18 (35%) had ventricular arrhythmias (95% confidence interval, 21% to 49%). In logistic regression analysis, increasing age (P < .02) and a left-sided neurological event (P < .01) were significant predictors of ST segment depression. Increasing numbers of atherosclerotic risk factors, a history of cardiac disease, and increasing or decreasing mean arterial pressure were not predictive of ST segment depression.

CONCLUSIONS

Patients with acute ischemic stroke or TIA have a 29% prevalence of ST segment depression within the first 5 days after their event. In comparison, the prevalence of ST depression is 2.5% to 8% in asymptomatic adults and 43% to 60% in patients with symptomatic coronary artery disease. The association of ST segment depression with left-sided neurological events suggests that the electrocardiographic changes are in part neurologically mediated. Further study is necessary to better define the brain-heart interaction and to determine whether ST segment depression in patients with ischemic stroke or TIA reflects underlying coronary artery disease.

The ankle-brachial index as a predictor of survival in patients with peripheral vascular disease

OBJECTIVE

To determine whether the ankle-brachial index (ABI) predicts survival rates among patients with peripheral vascular disease.

DESIGN

A retrospective survival analysis of patients with abnormal ABIs who visited the authors' blood-flow laboratory during 1987. The National Death Index was used to ascertain survival status for all patients up to January 1, 1992. Kaplan-Meier and Cox proportional hazards analyses were used to determine the relationship between increasing lower-extremity ischemia, measured by ABI, and survival time. Clinical characteristics controlled for included age, smoking history, gender, and comorbidities, as well as the presence of lower-extremity rest pain, ulcer, or gangrene.

SETTING

A university hospital blood-flow laboratory.

PATIENTS/PARTICIPANTS

Four hundred twenty-two patients who had no prior history of lower-extremity vascular procedures and who had ABIs < 0.92 in 1987.

RESULTS

Cumulative survival probabilities at 52 months' (4.3 years') follow-up were 69% for patients who had ABIs = 0.5-0.91, 62% for patients who had ABIs = 0.31-0.49, and 47% for patients who had ABIs < or = 0.3. In multivariate Cox proportional hazard analysis, the relative hazard of death was 1.8 (95% confidence interval = 1.2-2.9, p < 0.01) for the patients who had ABIs < or = 0.3 compared with the patients who had ABIs 0.5-0.91. Other independent predictors of poorer survival included age > 65 years (p < 0.001); a diagnosis of cancer, renal failure, or chronic lung disease (p < 0.001); and congestive heart failure (p < 0.04).

CONCLUSION

The ABI is a powerful tool for predicting survival in patients with peripheral vascular disease. Patients with ABIs < or = 0.3 have significantly poorer survival than do patients with ABIs 0.31-0.91. Further study is needed to determine whether aggressive coronary risk-factor modification, a work-up for undiagnosed coronary or cerebrovascular atherosclerotic disease, or aggressive therapy for known atherosclerosis can improve survival of patients with ABIs < or = 0.3.

Gender differences in interventional management of peripheral vascular disease: evidence from a blood flow laboratory population

Recent studies of gender differences in the treatment of coronary artery disease have concluded that female patients often receive less aggressive care than male patients. This study compares rates of lower extremity surgical and endovascular procedures by gender for peripheral vascular disease patients seen in the blood flow laboratory at our institution in 1987. Revascularization rates were compared for 192 female and 218 male patients with abnormal blood flow examinations and no prior lower extremity procedures. Female patients were older (3.3 years; p < 0.02), had a lower prevalence of ankle/brachial indices greater than 0.5 (64.2% of males vs. 51.8% of females; p < 0.01), a higher prevalence of hypertension (p < 0.03), and a lower prevalence of smoking (p < 0.02). No significant baseline differences were found for the prevalence of limb salvage indications or other comorbid conditions. A total of 41 women (21.4%) and 64 men (29.4%) underwent subsequent lower extremity surgical or endovascular procedures in 1987 (p = 0.08). Men had a significantly higher procedure rate among the 311 patients without limb salvage indications (p = 0.03). When statistically significant covariates such as limb salvage, age, ankle/brachial index, comorbidity, and smoking are controlled for in logistic regression analysis, men were found to have more than twice the chance of being selected for procedures (p = 0.009). Although limited to practice patterns at one institution, these results suggest that other centers should examine criteria for interventional therapy in mild-to-moderate peripheral vascular disease.