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Biomedical subjects

S Madhavan

Publications and source records attributed to S Madhavan.

At least 55 records · Page 3Linked to original sources

Effect of long-acting and short-acting calcium antagonists on cardiovascular outcomes in hypertensive patients.

BACKGROUND: Short-acting calcium antagonists may increase coronary artery morbidity, mortality, and non-cardiovascular complications in hypertensive patients. We assessed whether this association was also true for long-acting calcium antagonists. METHODS: We did a case-control study, which was nested within a systematic hypertension control programme for a prospective cohort of 4350 people (first seen 1981-94). Cases (n = 189) were hypertensive patients who had had a first cardiovascular event, including all cardiovascular deaths and hospitalisations, between 1989 and 1995. Controls (n = 189) were individually matched to cases for sex, ethnic origin, age, type of previous antihypertensive treatment, year of entry into the study, and length of follow-up. We collected data on any prescribed drug regimen that was being taken on the event data for cases and on the same date for matched controls. Calcium antagonists were classified by duration of action. FINDINGS: Compared with those on beta-blocker monotherapy, patients on long-acting calcium antagonists (n = 136) had no increased risk of a cardiovascular event (adjusted odds ratio 0.76 [95% CI 0.41-1.43]), whereas patients on short-acting calcium antagonists (n = 27) were at significantly greater risk (adjusted odds ratio 3.88 [1.15-13.11], p = 0.029). Among 38 matched pairs who were both on calcium antagonists, the adjusted risk ratio for short-acting versus long-acting was 8.56 (1.88-38.97), p < 0.01. INTERPRETATION: Long-acting and short-acting calcium antagonists differ in cardiovascular outcomes. Consistent with earlier findings, the use of short-acting calcium antagonists was associated with increased risk of a cardiovascular event. This finding highlights the need to complete on-going clinical trials so that the relative cardiovascular impact of various antihypertensive agents can be assessed.

Antihypertensive Agents↗

Plasma renin activity: a risk factor for myocardial infarction in hypertensive patients.

To determine whether pretreatment plasma renin activity (PRA), without accompanying 24-h urine sodium, can predict myocardial infarction (MI), the PRA levels of 2,902 hypertensive patients [white (38%), male (65%), median age 55 years], with mean entry blood pressure (BP) of 150/97 mm Hg were examined. During an average 3.6 years follow-up (87% > or = 9 months), there were 55 MIs, 21 strokes, and 16 other cardiovascular disease (CVD) deaths. Classification of PRA levels into 3 renin strata [high (H) PRA > or = 4.5 (n = 354), normal (N) 0.75 to 4.49 (n = 1,622), and low (L) < 0.75 (n = 926) ng/mL/h] yielded subgroups that did not differ in LVH (9% v 11%) or smoking prevalence (26% v 25%) but high versus low PRA subjects included more aged < 55 years (64% v 53%); white (49% v 25%); men (79% v 52%); cholesterol > or = 6.3 mmol/L (33% v 25%); all P values < .01. MI rates per 1,000/year were H: 9.3, N: 5.5, L: 2.5 (H v L, RR = 3.8, 95% CI: 1.7 to 8.4). A similar relationship was seen with total CVD (H: 12.5, N: 9.3, L: 5.2; RR = 2.4, 95% CI: 1.3 to 4.5) and all-cause mortality (H: 7.0, N: 6.2, L: 2.5; RR = 2.8, 95% CI: 1.2 to 6.8) but not CVA (H: 1.6, N: 2.0, L: 1.9). In a Cox survival analysis only renin, age, sex, smoking, LVH, and cholesterol were significantly (P < .02) related to MI occurrence. There was, for every 2 unit increase in PRA, an overall 25% increase in MI incidence. Among hypertensive subjects, PRA level (without urine sodium), is independently and directly associated with the incidence of MI.

Black People↗

The gift relationship between pharmaceutical companies and physicians: an exploratory survey of physicians.

The purpose of this exploratory study was to survey physicians' attitudes surrounding the 'gift relationship' between pharmaceutical companies and physicians. A survey was mailed to 1000 randomly selected West Virginia physicians, of which 283 (28.3%) responses were received. The most commonly received gifts reported by the study physicians were trinkets (77.4%), followed by books (41.7%) and meals (41%). Principal component analysis and varimax rotation identified seven physician belief constructs. The mean ratings of the constructs indicated that the physicians slightly agreed that pharmaceutical companies give gifts to physicians to influence their prescribing, moderately disagreed that they do so as a form of professional recognition of physicians, and strongly disagreed that their prescribing behaviour could be influenced by the gifts they receive. Physicians slightly disagreed that pharmaceutical companies' sponsoring of CME programmes are only promotional gimmicks. Although the study physicians slightly disagreed that it may be inappropriate for them to accept gifts from pharmaceutical companies, they seemed slightly averse to having 'gift relationships' between pharmaceutical companies and physicians made public. Correlation analysis suggested that physicians who have a large number of patients in their practice, see a larger number of patients per day, or write a large number of prescriptions per day are more likely to be offered gifts by pharmaceutical companies, and they are also more likely to condone the practice of gift giving and receiving.

Attitude of Health Personnel↗

Urinary sodium excretion and myocardial infarction in hypertensive patients: a prospective cohort study.

Reduced-sodium diets are frequently recommended for hypertensive patients. To determine the relation of sodium intake to subsequent cardiovascular disease, 24-h urinary excretion of sodium, potassium, and creatinine and plasma renin activity (PRA) were measured in 2937 mildly and moderately hypertensive patients unmedicated for > or = 3-4 wk. Morbidity and mortality in these treated subjects were ascertained. Subjects were stratified by sex-specific quartiles of urinary sodium excretion; race, cardiovascular status, and blood pressure before and during treatment were similar for each stratum. Patients with lower urinary sodium excretion were thinner, excreted less potassium, and had higher PRA. During an average 3.8-y follow-up, 55 myocardial infarctions (MIs) occurred. Incidence of MIs and urinary sodium excretion were inversely associated in the total population and in males but not in females. In males, age- and race-adjusted MI incidence in the lowest compared with the highest quartile of urinary sodium excretion was 11.5 compared with 2.5 (RR: 4.3; 95% CI: 1.7, 10.6). No association was observed between mortality from causes other than cardiovascular disease (n = 11) and urinary sodium excretion. There was a significant linear trend in proportions of MI by quartile of urinary sodium excretion, with a breakpoint after the lowest quartile. In Cox multivariate analysis, the logarithm of PRA, age, systolic blood pressure, and cholesterol as continuous variables, as well as left ventricular hypertrophy and smoking, had a direct association and urinary sodium excretion an inverse, independent association (P = 0.036) with incidence of MI.

Cardiovascular Diseases↗

Nativity, race, and mortality: influence of region of birth on mortality of US-born residents of New York City.

Among non-Hispanic black and white residents of New York City the association between birthplace by region (South, West/ Midwest, and Northeast) within the United States and mortality was determined by linking mortality records for 1988-1992 with the 1990 United States census data for New York City. Age-adjusted death rates computed by birthplace for blacks and whites were examined and also compared with total US data. The results indicate that death rates for New Yorkers generally exceed those of the United States overall, and black rates exceed those of whites. Moreover, Southern-born blacks have substantially higher death rates than do blacks born in the Northeast. The most striking variations are for cancer and diseases of the heart. Deaths from AIDS and homicide are higher among blacks than among whites, but the rates for Southern-born blacks do not exceed those for Northeastern-born blacks. For whites those born in the South have higher death rates overall than those born in the Northeast, but differences in cause-specific mortality are less consistent than for blacks. The results reveal substantial heterogeneity of health status based on nativity, among blacks in particular. To understand the role of the related factors, both genetic and environmental, further population and epidemiologic studies are important.

Adult↗

The influence of birthplace on mortality among Hispanic residents of New York City.

To determine the mortality experience of Hispanic residents of New York City and the influence of birthplace on their mortality rates, NYC Department of Health mortality records for 1988 to 1992 were linked for analysis with 1990 United States census data for New York City. Age-specific death rates for all Hispanics were compared by birthplace with those of non-Hispanic whites. Age-adjusted death rates were also compared. Overall, Hispanics had death rates lower than non-Hispanic blacks, and death rates similar to those of non-Hispanic whites. Hispanics had higher rates of death from HIV-infection, diabetes, stroke/hypertensive disease, cirrhosis and homicide, and fewer deaths from cancer and coronary heart disease than did non-Hispanic whites. Moreover, there were substantial differences in mortality between Hispanic subgroups categorized by birthplace. Migrants from Puerto Rico had the highest, and those from Central and South America the lowest mortality rates. United States-born Hispanics, although younger, had age-adjusted mortality rates higher than New York City non-Hispanic whites. In summary, the mortality of Hispanics generally approximated that of non-Hispanic whites, and was lower than that of non-Hispanic blacks. However, stratification of Hispanics by birthplace revealed substantial variation within the Hispanic population of New York City.

Adolescent↗

Nativity, race, and mortality: favorable impact of birth outside the United States on mortality in New York City.

To determine the association of birthplace (US-born vs. foreign-born) with mortality among blacks and whites in New York City, we examined death records for 5 years from 1988 to 1992 and the 1990 census data. Mortality rates by race and birthplace were compared for all causes of death and for specific causes. Although overall death rates for blacks generally exceeded those for whites (1224.8 per 100,000 inhabitants vs. 721.4 for males and 593.7 vs. 393.1 for females), foreign-born blacks had death rates (664.6 for males and 350.2 for females) slightly lower than those for whites. The most striking variation among blacks was among those aged 25 to 64 years. US-born black males were three times as likely (1588.9 vs. 525.2) and US-born black females were more than 2.5 times as likely (673.5 vs. 263.4) to die as were foreign-born blacks. Among US-born blacks AIDS, homicide, and cancer for males and AIDS, heart disease, and cancer for females were the most important determinants of excess deaths, defined as the difference between observed deaths and expected deaths; these causes of death account for about half of the excess deaths for each sex. Among whites natives generally had higher death rates than migrants, but less prominently and consistently so than for blacks. Excess mortality of blacks is largely explained by higher death rates of US-born compared with foreign-born Americans.

Adolescent↗

The association between birthplace and mortality from cardiovascular causes among black and white residents of New York City.

BACKGROUND: Life expectancy is shorter and mortality from cardiovascular disease higher among blacks than among whites in the United States. We studied whether place of birth was associated with mortality from cardiovascular causes among non-Hispanic black and white residents of New York City. METHODS: We linked mortality records from 1988 through 1992 with 1990 U.S. census data for New York City. Mortality data for blacks born in the U.S. South and Northeast and in the Caribbean were compared with those for whites born in the Northeast. RESULTS: Among blacks, the rates of overall mortality and mortality from cardiovascular causes exceeded those among whites. Among persons born in the Northeast, the rates of death from cardiovascular disease for white men (285 per 100,000), as compared with black men (299), and for white women (155), as compared with black women (165), were similar. However, Southern-born black men and women both had mortality from cardiovascular disease that was substantially higher than that of their counterparts born in the Northeast, and Caribbean-born blacks had rates substantially lower than their Northeastern-born counterparts. The differences among the groups in the rates of death from coronary heart disease were greater than those for death due to stroke or hypertension. In each category defined by age and sex, Caribbean-born blacks had significantly lower rates of death from coronary heart disease than did whites. Black men who were 25 to 44 years of age and were born in the South had a rate of death from coronary heart disease that was 30 percent higher than that of Northeastern-born blacks, and four times that of Caribbean-born blacks of the same sex and age. CONCLUSIONS: The higher rate of mortality from cardiovascular causes among blacks, as compared with whites, in New York City masks substantial variation among blacks based on their place of birth.

Adult↗

Antihypertensive Drug Therapy. The effect of JNC criteria on prescribing patterns and patient status through the first year.

This study was designed to evaluate the impact of the protocol-driven antihypertensive therapy on outcomes guided by the Joint National Committee (JNC) on Detection, Evaluation, and Treatment of high blood pressure. In a systematic hypertension control program for union employees conducted in New York City, untreated patients who began treatment on monotherapy guided by JNC recommendations during three representative periods: I-pre-JNC IV (1986-1987); II-post-JNC IV (1990-1991); and III (JNC V)-period of application of what were later published as JNC-V guidelines (1992) were observed during 1 year of treatment. A total of 550 presumably untreated patients were prescribed either diuretics, beta-blockers, calcium channel blockers, or angiotensin converting enzyme inhibitors. There were 231 in period I, 213 in II, and 106 in III. The patient composition over time became more predominantly female and Hispanic (I to III: 28% to 34%, and 35% to 45%, respectively). The main outcome measures were type of drug first prescribed and the outcomes at the end of 1 year-changes in blood pressure, clinical chemistry measures and therapy, and clinic attendance are dropout rate. The pattern of first drug prescription changed from 85% to 90% of patients given diuretics or beta-blockers in I to 90% begun on calcium channel blockers or angiotensin converting enzyme inhibitors in II and finally, to an even distribution of drugs in III. Blood pressure response was similar across the three periods, 135/89 mm Hg (I), 138/89 (II), and 140/89 (III). Proportion of patients remaining on their initial drug in each period was fairly similar (60%, 67%, and 69%). Scheduled clinic visits fell significantly from 7.4 visits in I, 6.9 in II, and 6.4 in III (I upsilon III P = .004). Dropouts diminished significantly from 17% in I, to 10% in II, and 9% in III (I upsilon II or III P = .045). Modest positive changes in cholesterol and fasting blood sugar level occurred over time. In this general community setting, dramatic shifts in the choice of initial drug based upon application of JNC guidelines had little discernable impact on short term patient outcomes.

Analysis of Variance↗

Cancer mortality of Chinese in New York City 1988-1992.

BACKGROUND: This study examines cancer mortality among Chinese migrants in New York City, and compares it with that of residents of China as well as New York City whites. METHOD: Mortality records for 1988-1992 from the New York City Department of Health, and the 1990 US census data for New York City were used for the analysis. Age-specific deaths and the population of urban China reported by the World Health Organization were also used for comparison. Age-adjusted death rates by gender for Chinese and whites in New York City, as well as for Chinese in China were computed using the world standard population. RESULTS: New York Chinese had lower mortality rates for all causes, total cancer, oesophageal and lung cancer deaths than did either New York whites or Chinese in China in both genders. However, they had lower death rates than New York whites, but similar to those in China, for colon cancer in both genders, and breast cancer in females. By contrast, New York Chinese had higher death rates for nasopharyngeal cancer than either New York City whites or Chinese in China. Stomach and liver cancer death rates in New York Chinese fell between those in China and New York City whites. CONCLUSIONS: Cancer mortality rates among Chinese migrants in New York City being the lowest for total cancer and some types of cancers, did not follow the usual pattern of migrants (an intermediate position between rates of native New Yorkers and Chinese in homeland China). However, substantial variations in certain cancer-specific mortality by geography were observed.

Adult↗

Renal function during antihypertensive treatment.

To determine the association of renal function and the course of blood pressure in antihypertensive therapy, we studied the changes in serum creatinine as a measure of renal function and in-treatment blood pressure in black and white hypertensive patients. We measured serum creatinine in 2125 mild and moderately hypertensive men during treatment over an average of 5 years. Both unadjusted mean initial and final serum creatinine of 758 blacks (113 and 117 mumol/L respectively) were significantly higher than those of 1367 whites (108 and 107 mumol/L), with a small increase of 4 mumol/L (p < 0.01) for blacks and a fall of 0.9 mumol/L (p > 0.05) for whites. Less than 2% of all patients attained or remained at a final serum creatinine of 177 mumol/L or more. Of this small group (3% blacks, 1.4% whites), 31% had proteinuria at entry. After stratification by in-treatment diastolic blood pressure (< 95 and > or = 95 mm Hg) in each race, mean slopes of reciprocal serum creatinine were estimated, adjusting for age at entry, initial serum creatinine, diastolic pressure, and body-mass index by analysis of covariance. The two adjusted mean slopes did not differ significantly within each race. Multiple regression analysis confirmed that in-treatment diastolic pressure was not independently associated with final serum creatinine. The change in renal function was most likely a reflection of regression towards the mean, and does not support the view that antihypertensive treatment is an important determinant of renal function in mild-to-moderate hypertensive patients. Patients with substantial renal insufficiency may have pre-existing intrinsic renal disease.

Antihypertensive Agents↗

Angina pectoris by Rose questionnaire does not predict cardiovascular disease in treated hypertensive patients.

OBJECTIVE: To determine the predictive value of angina pectoris diagnosed by Rose questionnaire for cardiovascular disease among treated hypertensives. METHODS: The cardiovascular experience of 4093 patients who had no history of cardiovascular disease and had been administered the Rose questionnaire for angina in a worksite treatment program was evaluated. RESULTS: Among 2659 men and 1434 women of similar age (53 versus 54 years), the race distribution was 44 versus 31% whites, 27 versus 41% blacks and 29 versus 28% Hispanics. Overall, the prevalence of angina by Rose questionnaire in women (15%) was twice that in men (7%) in all three races, with Hispanics having the highest (20 versus 10%) prevalence. Those with angina (Rose-plus) and those without (Rose-minus) had similar initial and final blood pressures. In 4.0 years of average follow-up study, the crude incidence rates (per 1000 person-years) of the recorded 120 myocardial infarctions and 35 strokes did not differ significantly between Rose-plus and Rose-minus patients, except for myocardial infarction in Hispanic men (20.5 versus 5.9). When myocardial infarction incidence was adjusted for age within each sex-race subgroup, only Rose-plus Hispanic men had a significantly greater relative risk with Rose-minus as referent (relative risk 3.13, 95% confidence interval 1.31-7.50). Overall, in the Cox proportional hazards regression model, angina by Rose questionnaire was not predictive of myocardial infarction after accounting for other recognized risk factors. CONCLUSIONS: The present data suggest that the Rose questionnaire as a diagnostic tool for angina is not predictive of subsequent clinical events among treated hypertensive patients.

Adult↗

Low urinary sodium is associated with greater risk of myocardial infarction among treated hypertensive men.

A sodium-reduced diet is frequently recommended for hypertensive individuals. To determine the relationship of sodium intake to subsequent cardiovascular disease, we assessed the experience of participants in a worksite-based cohort of hypertensive subjects. The 24-hour urinary excretion of sodium (UNaV), potassium, creatinine, and plasma renin activity was measured in 2937 mildly and moderately hypertensive subjects who were unmedicated for at least 3-4 weeks. Morbidity and mortality in these systematically treated subjects were ascertained. Men and women were stratified according to sex-specific quartiles of UNaV. Subjects in these strata were similar in race, cardiovascular status, and pretreatment and intreatment blood pressure. Subjects with lower UNaV were thinner, excreted less potassium, and had higher plasma renin activity. During an average 3.8 years of follow-up, a total of 55 myocardial infarctions occurred. Myocardial infarction and UNaV were inversely associated in the total population and in men but not in women, who sustained only nine events. In men, age- and race-adjusted myocardial infarction incidence in the lowest versus highest UNaV quartile was 11.5 versus 2.5 (relative risk, 4.3, 95% confidence interval, 1.7-10.6). No association was observed between non-cardiovascular disease mortality (n = 11) and UNaV. There was a significant linear trend in proportions of myocardial infarction by UNaV quartile, with a break point after the lowest UNaV quartile.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Isolated diastolic hypertension. A favorable finding among young and middle-aged hypertensive subjects.

To identify pretreatment characteristics associated with subsequent myocardial infarction in young and middle-aged previously untreated hypertensive individuals, we examined the experience of 1560 participants in a work-site hypertension control program who were younger than 60 years. Subjects were categorized by initial blood pressure as having isolated diastolic hypertension (< 160/> or = 90 mm Hg, n = 965) or combined systolic and diastolic hypertension (> or = 160/> or = 90 mm Hg, n = 595). During 4.5 years of follow-up, there were 24 myocardial infarctions, yielding an overall incidence of 3.89 per 1000 person-years. Subjects with systolic/diastolic hypertension were older, had higher cholesterol and blood sugar levels, and included more smokers and people with left ventricular hypertrophy on electrocardiogram than those with isolated diastolic hypertension. Age-adjusted incidence rates for myocardial infarction were 5.20 and 2.21 per 1000 person-years in systolic/diastolic hypertension and isolated diastolic hypertension, respectively, and the relative risk of systolic/diastolic hypertension was 2.31 (95% confidence interval, 1.29-4.15). Among subjects with isolated diastolic hypertension, no myocardial infarction occurred in those with systolic pressure less than 140 mm Hg. Cox regression analysis including other known risk factors showed that pulse pressure, as a continuous variable (hazards ratio, 1.54; 95% confidence interval, 1.08-2.20), and type of hypertension, ie, systolic/diastolic hypertension versus isolated diastolic hypertension (hazards ratio, 2.11; 95% confidence interval, 1.08-4.13), were independently associated with myocardial infarction. These results suggest that young and middle-aged treated hypertensive individuals with normal pretreatment systolic pressure enjoy a more favorable prognosis than do those with systolic elevation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Differential mortality in New York City (1988-1992). Part One: excess mortality among non-Hispanic blacks.

To determine the distribution of mortality for non-Hispanic blacks and non-Hispanic whites in New York City, death certificates issued in New York City during 1988 through 1992, and the relevant 1990 US census data for New York City, have been examined. Age-adjusted death rates for blacks and whites by gender and cause of death were computed based on the US population in 1940. Also, standard mortality ratios and excess mortality were calculated using the New York City mortality rate as reference. The results showed that New York City blacks had higher age-adjusted death rates than whites regardless of cause, including stroke, AIDS, homicide, and diabetes. The rate for New York City blacks was also higher than the US total for both genders. Using New York City mortality rates as a reference, more than 80% of excess deaths in blacks occurred before age 65. Injury/poisoning was the leading cause of excess death (20.1%) in black males, while in black females, cardiovascular disease was the largest single cause of excess deaths (24.8%). The higher death rates, especially premature death, of blacks in New York City are related to conditions such as violence, substance abuse, and AIDS, for which prevention rather than medical care is the more likely solution, as well as to cardiovascular diseases, where both prevention through behavioral change, and health and medical care, can influence outcome.

Black or African American↗

Differential mortality in New York City (1988-1992). Part Two: excess mortality in the south Bronx.

To display the extent of variations in mortality according to geographic regions in New York City, we have compared mortality in New York City as a whole with that of the South Bronx. Mortality records for 1988 to 1992 and 1990 US census data for New York City were linked. The 471,000 residents of the South Bronx were younger, less educated, and more likely to lack health insurance than other New Yorkers. Using age- and gender-stratified populations and mortality in New York City as standards, age-adjusted death rates and excess mortality in the South Bronx were determined. All-cause mortality in the South Bronx was 26% higher than the city as a whole. Mortality for AIDS, injury and poisoning, drug and alcohol abuse, and cardiovascular diseases were 50% to 100% higher in the South Bronx than in New York City; years of potential life lost before age 65 in the South Bronx were 41.6% and 44.2% higher for men and women, respectively, than in New York City; AIDS accounted for the largest single share of excess premature deaths (21.8%). In summary, inequalities in health status, reflected by higher mortality rates in the South Bronx, are consistent with, and perhaps caused by, lower socioeconomic status and deficient medical care among residents of this inner-city community.

Cause of Death↗

Measures of blood pressure and myocardial infarction in treated hypertensive patients.

OBJECTIVE: To identify entry characteristics associated with subsequent myocardial infarction in treated hypertensive patients. DESIGN: Nested case-control study and cohort study. SETTING AND PATIENTS: The 5730 participants (mean age 53 years; 61% male and 45% Caucasian) were selected from a worksite-based, union-sponsored, systematic hypertension control program from 1973 to 1992. METHODS: In the case-control study myocardial infarction cases were matched by age, sex, year of entry to the program, years of follow-up and previous treatment status (treated or untreated) with non-event subjects. Baseline clinical and biochemical characteristics were analyzed with regard to the outcome of myocardial infarction, using univariate and multivariate analyses, respectively, in case-control and cohort studies. RESULTS: During 5.43 years of follow-up the incidence of myocardial infarction was 6.75/1000 person-years. Univariate analysis indicated that myocardial infarction cases had higher cholesterol level and were more likely to have a previous history of diabetes than controls. The initial systolic blood pressure and pulse pressure of cases were significantly higher than in controls. Logistic regression models indicated that initial pulse pressure, either as a continuous or as a categorical variable, was the only measure of blood pressure independently associated with myocardial infarction after adjustment for other risk factors. Analysis of the experience of the total 5730 as well as 2445 previously untreated patients with a cohort study generated identical results. CONCLUSION: A large pulse pressure difference appears to be the most powerful measure available of initial blood pressure to identify, in advance, those hypertensive patients at greatest risk for a subsequent myocardial infarction.

Blood Glucose↗