[Current application of placebo in Chinese clinical studies in past 30 years].

To analyze and discuss placebo-related information in clinical research literatures in the past 30 years, including placebo's dosage form, ingredients, preparation process and quality control. Effort were made to research the CNKI. full-text database to preliminary find 700 placebo-related clinical research literature, screen out 301 eligible articles by hand, read the literatures to extract placebo-related information and make statistics and discussions. According to the results, Chinese randomized placebo-controlled clinical studies were characterized by diverse dosage forms of placebo with lack of reports for components, as evidenced by the only 17 literatures describing placebo's preparation or specific composition among the 301 literatures. Placebo-controlled clinical trials covered a wide range of disease spectra, but with a specific tropism of diseases in terms of system classification. Although placebo plays a key role in blinded clinical studies, researchers made less records of placebo, perhaps because they paid less attention to placebo or more attention to the research process or restricted by other objective conditions. Moreover, placebo production, quality control and quality evaluation also need to be further standardized.

[Prospective study on associations between levels of total cholesterol, triglyceride and risk of ischemic and hemorrhagic strokes].

OBJECTIVE: To explore associations between levels of total cholesterol (TC), triglyceride (TG) and incidence of ischemic and hemorrhagic strokes in populations. METHODS: Baseline investigations on stroke-related risk factors and physical examinations were performed in 10 093 (> 35 years) stroke-free urban community residents from 5 cities in China during May to July in 1987, follow-up investigations on stroke events were made during 1998 to 2000. The hazard ratios and 95% confidence intervals (CI) of ischemic and hemorrhagic strokes in middle, high tertiles of baseline TC or TG levels were compared with low baseline tertile residents using the Cox regression model. RESULTS: There were 491 first strokes during the 8-years cohort follow-up. Compared with the low tertile, risk of ischemic stroke in the middle and high tertiles of TC level was increased by 61% (HR: 1.61, 95%CI: 1.14-2.27) and 58% (HR: 1.58, 95%CI: 1.12-2.22) after adjustments for DBP, age, sex and other variables in the Cox proportional hazards model. Compared with the low tertile, risk of ischemic stroke in the high tertile of TG level was increased by 43% (HR: 1.43, 95%CI: 1.02-2.00). However, risk of hemorrhagic stroke in the middle and high tertiles of TC level decreased by 12% (HR: 0.88, 95%CI: 0.64-1.22) and 33% (HR: 0.67, 95%CI: 0.48-0.95) compared with the low tertile. CONCLUSIONS: Elevated serum TC and TG are independent risk factors for risk of ischemic stroke. However, low TC was related with increased risk of hemorrhagic stroke.

[Study on the relationship between hypertension management and the risk of stroke at community level].

OBJECTIVE: To observe whether the community-based management for patients with hypertension can reduce the incidence of stroke. METHODS: Sample of this study included 36 863 people aged 35 years or more who came from a cohort consisting three communities from Tiantan Hospital, Puren Hospital and the Gymnasium Road Hospital in Beijing, based on the surveys on the Integrated Community Intervention Measures of Cerebro-vascular Diseases. Some patients with hypertension in this cohort were followed up and under management. First-ever stroke was considered as the end-point event. RESULTS: In both groups diagnosed as borderline hypertension or definite hypertension group, the rates of management and control showed an annual increase. The management rate for women was higher, but the control rate was lower (P < 0.05) than that for men. In the third year of this study, the control rate was nearly 18%. With the qualification of control rate, the risk factors of overall stroke, ischemic stroke or hemorrhagic stroke reduced gradually, and the qualification of control rate showed more effects on hemorrhagic stroke. The qualification of control rate in the three years could cause the risk factors of total stroke, ischemic stroke or hemorrhagic stroke to reduce by 25.7%, 19.1%, 27.4%, respectively. When comparing with blood pressure level at < 160/95 mm Hg (1 mm Hg = 0.133 kPa), the level of < 140/90 mm Hg could reduce the risk factors as: 12.3% to total stroke, 12.8% to ischemic stroke and 14.9% to hemorrhagic stroke. CONCLUSION: Programs as long-term followed-up and management for patients with hypertension, and control the blood pressure at low level etc. could significantly reduce the incidence of stroke.

[Evaluation on a community-based intervention program among people with different risk factors of stroke].

OBJECTIVE: To evaluate the effect of a long-term community-based intervention program on risk factors of stroke among people with different risk factors. METHODS: In 1987,2 geographically separated communities with 10 000 registered residents of each, were selected as either intervention or control communities in Beijing and Changsha. A cohort containing 2700 subjects at the age of 35 years or older,and free of stroke were sampled from each community. The baseline survey was conducted to screen the subjects at high risk for intervention and there were 5319 and 5506 subjects enrolled in intervention and control cohorts,respectively. Then,a program for controlling the risk factors of stroke was initiated in the intervention cohort and health education was provided to the whole intervention community. A follow-up survey was conducted in 1999. The information on incidence and mortality of stroke was collected. RESULTS: Comparing with the control cohort, the risk of incidence and mortality of stroke decreased by 22 % ( HR = 0.78,95 % CI:0. 66-0.92) and 73 % (HR = 0.27,95 % CI:0. 17-0.42) in intervention cohort. The risks of stroke were lower in intervention cohort than in control cohort among almost all of the sub-groups with or without risk factors of stroke except for being male,current smokers and current alcohol drinkers. The risk of death caused by stroke decreased significantly in those with or without the risk factors of stroke. CONCLUSION: The long-term community intervention on the risk factors of stroke could effectively reduce the risk of incidence and mortality of stroke among people with or without the risk factors of stroke. More attention should be paid to the males and those who smoke or drink alcohol.

Change in stroke incidence from a population-based intervention trial in three urban communities in China.

Stroke has been the main cause of death in most urban residents in China since the 1990s. A community-based intervention trial carried out in China aimed to reduce the incidence and mortality of stroke. In 1991, two well-matched communities each with approximately 50,000 people were selected as intervention or control communities in the urban areas of Beijing, Shanghai and Changsha. Regular health education and health promotion activities were carried out between 1991 and 2000 in the intervention communities but no special action was taken in the control communities. Both fatal and nonfatal stroke cases were meticulously registered during the study in the two communities to assess the effect of long-term intervention. The trend in stroke incidence and the effect of intervention on stroke incidence were analyzed using a Poisson regression model adjusted for age, sex, year and city. Between 1991 and 2000, 2,273 first-ever stroke cases were registered in the intervention communities and 3,015 in the control communities. Geographic variation and changes in the incidence of stroke and its subtypes were found among these 3 cities. Through 10 years of intervention, incidence risks of all, ischemic and hemorrhagic strokes decreased by 11.4% (relative risk 0.8959; 95% confidence interval, CI, 0.8483-0.9460; p < 0.0001), 13.2% (relative risk 0.8676; 95% CI 0.8054-0.9345; p = 0.0002) and 7.2% (relative risk 0.9283; 95% CI 0.8517-1.0117; p = 0.0899), respectively, in the intervention compared with control communities. Accordingly, comprehensive community-based intervention measures could effectively reduce the incidence of stroke in the population.

Subtype hypertension and risk of stroke in middle-aged and older Chinese: a 10-year follow-up study.

BACKGROUND AND PURPOSE: Hypertension is the most important indicator of stroke. We aim to compare the long-term effects of the subtypes of hypertension on the risk of stroke in a Chinese cohort. METHODS: A total of 26,587 subjects > or =35 years of age and free of stroke were recruited in 5 cities in 1987. The subtypes of hypertension were defined as isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), systolic and diastolic hypertension (SDH), as well as managed hypertension (MHT), according to the criteria of systolic blood pressure > or =140 or diastolic blood pressure >90 mm Hg or under antihypertensive treatment. The relative risks of stroke with the subtypes of hypertension, compared with normotensives, were estimated using the Cox model after adjustments for age, sex, and other confounders. RESULTS: The prevalence of hypertension was: ISH 7.1%, SDH 18.4%, IDH 6.7%, and MHT 3.9%. During a total of 233 437 person years of follow-up, 1107 subjects developed stroke (614 ischemic and 451 hemorrhagic events and 42 unclassified). SDH patients were at the highest risk of stroke among all the hypertensives. The hazard ratio and 95% CI was 2.96 (2.49 to 3.52) for all stroke, 4.05 (3.10 to 5.30) for hemorrhagic, and 2.33 (1.84 to 2.95) for ischemic stroke. Although the incidence of stroke was higher in the older population, the effect of hypertension, especially SDH, on hemorrhagic stroke is stronger in the middle-aged population. CONCLUSIONS: ISH and IDH are similarly prevalent in the population; both are independent predictors of stroke. Patients with SDH are at the highest risk of stroke and should be treated more aggressively.

Incidence and trends of stroke and its subtypes in China: results from three large cities.

BACKGROUND AND PURPOSE: To examine the incidence and trends of stroke and its major subtypes during the 1990s in 3 cities in China. METHODS: Stroke cases registered between 1991 to 2000 were initially identified through the stroke surveillance networks established in Beijing, Shanghai, and Changsha, and then confirmed by neurologists. RESULTS: The age-standardized incidence rates per 100,000 person years of overall first-ever stroke were 135.0 (95% CI, 126.5 to 144.6) in Beijing, 76.1 (70.6 to 82.6) in Shanghai, and 150.0 (141.3 to 160.0) in Changsha during the 1990s. Incidence of ischemic stroke (IS) was highest in Beijing, followed by Changsha and Shanghai; for intracerebral hemorrhage (ICH), the highest rate was found in Changsha, followed by Beijing and Shanghai. The same order as ICH was also observed for subarachnoid hemorrhage. The age-adjusted incidence of overall stroke and ICH for individuals > or =55 years of age in our populations was generally higher than that from Western populations. During the 1990s, ICH incidence decreased significantly at a rate of 12.0% per year in Beijing, 4.4% in Shanghai, and 7.7% in Changsha; in contrast, except for Changsha, IS incidence increased in Beijing (5.0% per year) and Shanghai (7.7%). CONCLUSIONS: There is a geographic variation in the incidence of stroke and its subtypes among these 3 cities, but the incidence of overall and hemorrhagic stroke in China is generally higher than that in the Western countries. Interestingly, the decrease in ICH and increase in IS during the past decade may reflect some underlying changes of risk factors in Chinese populations.

Effects of urban community intervention on 3-year survival and recurrence after first-ever stroke.

BACKGROUND AND PURPOSE: For the past 2 decades, stroke has been a principal cause of death in China, and stroke incidence tends to increase with the increase of stroke-related risk factors. The purpose of this study was to evaluate the effects of urban community-based intervention on 3-year survival and recurrence after first-ever stroke. METHODS: Two communities with a registered population of approximately 50 000 each were selected as either intervention or control communities in Beijing during 1991 to 2000. Comprehensive intervention measures including the management of high-risk population and the health education of whole community population were regularly implemented. Then the influence of community intervention on 3-year survival and recurrence after initial stroke was evaluated. RESULTS: Within 3 years, 41.85% of 736 patients in the intervention community died whereas 40.34% of 818 patients in the control community died. Of 223 cases from the intervention community, 26 (11.66%) had a recurrent stroke within 3 years versus 52 (20.80%) of 250 cases from the control community. The statistical difference was found. Compared with the control community, the death risk of first-ever stroke in the intervention community decreased by 26% (relative risk [RR]=0.74; 95% confidence interval [CI]: 0.61 to 0.89; P=0.002); especially, that of hemorrhagic stroke decreased by 39% (RR=0.61; 95%CI: 0.46 to 0.81; P=0.001). Compared with the control community, the recurrence risk of first-ever stroke from the intervention community decreased by 42% (RR=0.58; 95% CI: 0.34 to 1.00; P=0.048). CONCLUSIONS: Community intervention may be effective and beneficial to the recurrence prevention and survival improvement of stroke, especially hemorrhagic stroke.

Three-dimensional phase contrast velocity mapping acquisition improves wall shear stress estimation in vivo.

The purpose of this study was to evaluate and apply high-resolution three-dimensional phase contrast mapping for estimation of wall shear stress in vivo. A silicon pipe of 8 mm diameter with a 8.3 ml/s steady flow and the entrance of the carotid bifurcation in 10 young healthy volunteers aged 23.6 +/- 3.1 years was studied. Very high resolution three-dimensional and two-dimensional phase contrast mapping sequences with spatial resolutions of 0.31 x 0.31 x 1.5 mm(3) and 0.31 x 0.31 x 3 mm(3), respectively, were compared in vivo and in vitro. Wall shear stress was calculated using multi-sectored, three-dimensional paraboloid fitting. In comparison to the two-dimensional measurements, the three-dimensional method with only half the slice thickness gave higher signal-to-noise ratio and velocity-to-noise ratios both in vivo and in vitro. Wall shear stress derived from the three-dimensional velocity measurements did not differ from the two-dimensional velocity measurements either in vitro or in vivo. Mean wall shear stress was lowest and oscillatory shear index was highest at the outer wall, towards the carotid bifurcation. Three-dimensional velocity mapping increases resolution and image quality and allows estimation of wall shear stress patterns circumferentially and longitudinally in human arteries.

[Analysis of acute respiratory dysfunction as a risk factor of multiple injuries].

OBJECTIVE: To study the relationship between multiple injuries and acute respiratory dysfunction (ARD). METHODS: One hundred and ten patients with multiple injuries admitted during the last 6 years were retrospectively analyzed. With ARD as the dependent variable and other 11 factors as independent variables, all analysis was done statistically on computer to identify the complication of ARD as a risk factor. RESULTS: Multivariable and single argument analysis showed systemic inflammatory response syndrome (SIRS), pulmonary contusion, co-existing lung disease as chronic obstructive pulmonary disease (COPD) and pneumonia, moderate hemothorax and pneumothorax, duration of shock over 12 hours, age over 55 years, injury severity score(ISS)>24 were high risk factors. CONCLUSION: Patients with multiple injuries with high risk factors should be kept under closer observation in order to prevent ARD and multiple organ dysfunction syndromes (MODS).

Wall shear rates differ between the normal carotid, femoral, and brachial arteries: an in vivo MRI study.

PURPOSE: To investigate wall shear rates in vivo in the common carotid, brachial, and superficial femoral arteries using very high resolution magnetic resonance imaging (MRI) phase contrast measurements. MATERIALS AND METHODS: Mean, maximum, and minimum wall shear rate and an oscillatory shear index were measured for 20 volunteers, aged 23.3 +/- 1.9 years, in the three arteries, using phase contrast imaging with 0.0625 mm2 resolution and three-dimensional paraboloid fitting. RESULTS: The superficial femoral artery had the lowest mean (130.3 +/- 13.1 second(-1)), maximum (735.8 +/- 32.4 second(-1)), and minimum (-224.5 +/- 17.0 second(-1)) wall shear rate, as well as the highest oscillatory shear index (0.21 +/- 0.02). All values were significantly different (P < 0.05) from both the brachial artery and the common carotid artery values. The highest mean (333.3 +/- 13.6 second(-1)) and minimum (117.9 +/- 24.5 second(-1)) wall shear rates and the lowest oscillatory shear index (0 +/- 0) were found in the common carotid artery. CONCLUSION: It is possible to measure wall shear rate in vivo in different arteries using MRI with very high resolution. The findings exhibit the in vivo environment of wall shear rates and suggest a nonuniform distribution of wall shear rates throughout the arterial system.

[Community intervention on hypertension and stroke].

OBJECTIVE: To evaluate the community-based intervention on reduction of hypertension and stroke in different age groups and subtypes hypertension. METHODS: In 6 cities, 2 geographically separated communities with a registered population about 10 000 of each were selected as either intervention or control communities. A cohort containing 2 700 subjects, 35 years or older, and free of stroke were sampled from each community. The baseline survey was conducted to screen the subjects for intervention. In each city, a program for control of hypertension, heart diseases and diabetes was initiated in the intervention cohort and health education was provided to the whole intervention community. A follow-up survey was conducted 3 years later. RESULTS: Within 3 years, the prevalence of hypertension increased in both intervention and control cohorts, as well as in the middle and elderly cohorts, especially in the middle aged in control group. Among hypertensives in the intervention cohort, the rates of awareness, treatment and control of hypertension got improved. The incidence of stroke was 29% lower (HR = 0.71, 95% CI: 0.58 - 0.87) and mortality of stroke was 40% lower (HR = 0.60, 95% CI: 0.42 - 0.86) in the intervention cohort than the control cohort. The intervention was most effective in reduction of stroke for those with isolated systolic hypertension and combined systolic and diastolic hypertension (All P < 0.05). Meanwhile, all-cause mortality was 11% lower (HR = 0.89, 95% CI: 0.78 - 0.99) in the intervention cohort than in the control cohort. CONCLUSION: The community-based intervention was effective in controlling the development of hypertension and stroke, while the elderly people benefit more than the middle aged people from the intervention.

[Evaluation of effectiveness of intervention on risk factors for cerebrovascular disease in three cities of China].

OBJECTIVE: To evaluate the effects of community intervention on risk factors of cerebrovascular disease. METHODS: With cluster sampling, 2,586 and 2,723 women and men aged 35 to 74 were selected randomly as intervention cohort and control cohort, respectively, from about 300 thousand community population in Beijing, Shanghai and Changsha, during 1997 to 2000. Their blood pressure, levels of blood lipid, body mass index (BMI) were measured and status of smoking and alcohol consumption were surveyed as indices of evaluation. Health education for smoking quit, alcohol consumption restriction and reinforced treatment for diabetic and hypertensive patients were implemented in the intervention communities. And, 2,544 and 2,533 persons in the two cohorts responded three years after intervention, and then all the indices mentioned above were measure again for them. RESULTS: Average reduction in systolic blood pressure by 3.21 mm Hg and serum level of total cholesterol by 0.58 mmol/L was achieved in intervention cohort after intervention, but with 0.48 mmol/L increase in triglyceride. Average blood levels of both high density lipoprotein-cholesterol (HDL-C) and glucose increased in the two cohorts after intervention, but with 0.30 mmol/L net increase of blood glucose in control cohort. There was no significant difference in average increase of HDL-C between the two cohorts. BMI increased by 0.56 in control cohort, and no significant change in intervention cohort. Proportion of smoking decreased by 5.4% in men and 2.4% in women of intervention cohort, and no change in control cohort. CONCLUSION: Level of risk factors for cerebrovascular disease reduced significantly with community intervention.