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Biomedical subjects

C Ahn

Publications and source records attributed to C Ahn.

At least 109 records · Page 6Linked to original sources
PubMed1999

Incidence of new thromboembolic stroke in persons 62 years and older with chronic atrial fibrillation treated with warfarin versus aspirin.

OBJECTIVE: To investigate the incidence of new thromboembolic (TE) stroke in older persons with chronic atrial fibrillation treated with oral warfarin versus aspirin. DESIGN: In an observational study of 312 older persons with chronic atrial fibrillation, long-term aspirin 325 mg daily was administered to 187 persons, and oral warfarin, in a dose adjusted to maintain the international normalized ratio (INR) between 2.0 and 3.0, was administered to 115 persons. The incidence of new TE stroke was analyzed in persons treated with warfarin versus aspirin at 36 +/- 17 months (1 to 99 months) follow-up. SETTING: A large, long-term healthcare facility. PATIENTS: The patients included 208 women and 104 men, mean age 84 +/- 7 years (range 62 to 101 years). MEASUREMENTS AND MAIN RESULTS: Four of 125 persons (3%) on warfarin stopped taking warfarin compared with four of 187 persons (2%) on aspirin who stopped taking aspirin because of adverse effects (P not significant). In persons with prior stroke, the incidence of new TE stroke was 40% (27 of 67) in persons treated with warfarin versus 81% (56 of 69) in persons treated with aspirin (P < .001). In persons with no prior stroke, the incidence of new TE stroke was 22% (13 of 58) in persons treated with warfarin versus 56% (66 of 118) in persons treated with aspirin (P < .001). The incidence of new TE stroke in all subjects was 32% (40 of 125) in persons treated with warfarin versus 65% (122 of 187) in persons treated with aspirin (P < .001). Cox regression analysis showed that persons taking warfarin had a 76% less chance of developing a new TE stroke than those taking aspirin after controlling the confounding effects of other risk factors. CONCLUSION: In an observational study of older persons with chronic atrial fibrillation, persons treated with oral warfarin to maintain an INR between 2.0 and 3.0 had a significantly lower incidence of new TE stroke than persons treated with oral aspirin 325 mg daily.

Administration, Oral↗
PubMed1999

Incidence of heart failure in 2,737 older persons with and without diabetes mellitus.

STUDY OBJECTIVES: To investigate in older persons whether diabetes mellitus is an independent risk factor for congestive heart failure (CHF). DESIGN: A prospective study was performed in 2,737 older persons investigating the incidence of new CHF in persons with and without diabetes mellitus. SETTING: A long-term health-care facility. PATIENTS: Eight hundred sixty-five men and 1,872 women, with a mean age of 81+/-9 years. MEASUREMENTS AND RESULTS: At 43-month follow-up, new CHF developed in 272 of 690 persons (39%) with diabetes mellitus and in 467 of 2,047 persons (23%) without diabetes mellitus (p < 0.0001). Cox regression analysis showed that age (p = 0.0001, risk ratio = 1.048), hypertension (p = 0.0001, risk ratio = 2.524), coronary artery disease (p = 0.0001, risk ratio = 4.008), male gender (p = 0.0001, risk ratio = 1.399), and diabetes mellitus (p = 0.0003, risk ratio = 1.337) were significantly positively associated with the time to the development of CHF. CONCLUSIONS: Older persons with diabetes mellitus had a 1.3 times higher chance of developing CHF than those without diabetes mellitus after controlling the confounding effects of other prognostic variables.

Aged↗
PubMed1999

Cisplatin and infusional cytosine arabinoside for the treatment of colorectal adenocarcinoma: a phase II trial.

Based on the in vitro and in vivo synergy between cytosine arabinoside (Ara-C) and cis-diamminedichloroplatinum (cisplatin), we designed a phase II trial of Ara-C with cisplatin for patients with colorectal adenocarcinoma. Forty-eight eligible patients received continuous infusion Ara-C, 30 mg/m2/day over 72 hr, plus cisplatin, 30 mg/m2 for three doses at hours 12, 36, and 60 of the Ara-C infusion. The objective partial response rate for patients with colon carcinoma was 3% (1/32 patients; 95% CI, 0-16%) with a median response duration of 2.8 months. None of the 16 patients treated for rectal carcinoma responded. Myelosuppression was the most severe toxicity. Significant gastrointestinal and hepatic toxicities occurred in a small number of patients. Nephrotoxicity and neurotoxicity were mild. We conclude that the prolonged infusion of Ara-C in combination with divided doses of cisplatin offers no significant therapeutic advantage.

Adult↗
PubMed1999

Prognostic factors of diffuse proliferative lupus nephritis.

BACKGROUND: Diffuse proliferative lupus nephritis (DPLN) is the most severe form in lupus nephritis. PATIENTS AND METHODS: We retrospectively analyzed 90 DPLN patients who were confirmed by kidney biopsy and treated at least for 12 months to compare the effectiveness of treatment modalities and to investigate the prognostic factors of DPLN. The patients were categorized to intravenous cyclophosphamide pulse (CY) group and oral corticosteroid (with/without cytotoxic drug, PO) group. RESULTS: When the CY group (69 patients) and PO group (21 patients) were compared, there were no differences between two groups in sex, age, histologic chronicity index (CI, 4.55 vs 3.76; CY vs PO, respectively), mortality rate (4.3% vs 0%), remission rate of nephritis (at 3-year 59. 1 % vs 75.5%), renal survival rate (at 5-year 88.0% vs 91.7%) and complications of treatment, but significant differences in the frequency of nephrotic syndrome (66.7% vs 33.3%) and initial azotemia (30.4% vs 0%). histologic activity index (7.14 vs 4.33) and relapse rate (2.9% vs 42.9%). When the remission group (49 patients) and non-remission group (41 patients) were compared, CI, initial renal insufficiency, male sex and the duration of nephritis were the prognostic factors for remission in univariate analysis, and male sex (OR 10.99) and CI (OR 9.89) in multivariate analysis. When the remission group (35 patients) and non-remission (34 patients) group were compared in the CY group, CI was the prognostic factor in univariate analysis, and CI (OR 8.63) and male sex (OR 5.54) in multivariate analysis. The initial renal insufficiency (OR 12.74) and male sex (OR 7.99) were the prognostic factors for renal survival. The renal survival rate was 100% in remission-induced patients. CONCLUSION: We conclude that CI, male sex, initial renal insufficiency were the prognostic factors of DPLN, and treatment with oral corticosteroid could induce remission in patients who had mild histologic and clinical features. Therefore it would be necessary to evaluate the prognostic factors before the selection of treatment modality.

Adult↗
PubMed1998

Risk factors for new coronary events in older African-American men and women.

Independent risk factors for new coronary events in older African-American men were (1) age (risk ratio = 1.037), (2) cigarette smoking (risk ratio = 2.231), (3) hypertension (risk ratio = 2.531), (4) serum total cholesterol (risk ratio = 1.012), (5) serum high-density lipoprotein (HDL) cholesterol (inverse association) (risk ratio = 0.948), and (6) prior coronary artery disease (CAD) (risk ratio = 2.288). Independent risk factors for new coronary events in older African-American women were (1) cigarette smoking (risk ratio = 2.202), (2) hypertension (risk ratio = 2.344), (3) diabetes mellitus (risk ratio = 1.632), (4) serum total cholesterol (risk ratio = 1.008), (5) serum HDL cholesterol (inverse association) (risk ratio = 0.936), (6) age (risk ratio = 1.026), and (7) prior CAD (risk ratio = 2.368).

Black or African American↗
PubMed1998

An evaluation of phase I cancer clinical trial designs.

Phase I clinical trials are designed to identify an appropriate dose for experimentation in phase II and III studies. I present the results from a simulation study to evaluate the performance of nine phase I designs involving the standard design, the two-stage modified Storer's design, the two-stage Korn's design, the one-stage modified continual reassessment method (CRM) designs, and the two-stage modified CRM designs. I compare the performance of the above phase I designs in terms of the following criteria: (i) the proportion of the recommended maximum tolerated dose (MTD) at each dose level; (ii) the proportion of patients treated at each dose level; (iii) the average number of patients to complete the trial; (iv) the probability of toxicity observed; and (v) the average number of cohorts to complete the trial. In general, the one-stage modified CRM II and CRM III designs perform well compared with the other designs considered in this study. The one-stage modified CRM II and III designs require much fewer numbers of cohorts than do the two-stage modified CRM II and III designs. The one-stage modified CRM II and III designs avoid the criticisms of the original CRM by reducing the average number of cohorts and toxicity incidences, while estimating the MTD more accurately than does the standard design.

Antineoplastic Agents↗
PubMed1998

Risk factors for new thromboembolic stroke in patients > or = 62 years of age with chronic atrial fibrillation.

In a prospective study of 312 older patients with chronic atrial fibrillation, at 36-month follow-up evaluation, new thromboembolic stroke developed in 162 of 312 patients (52%). Significant independent risk factors for new thromboembolic stroke were prior stroke (risk ratio = 1.6), rheumatic mitral stenosis (risk ratio = 2.0), left ventricular (LV) hypertrophy (risk ratio = 2.8), abnormal LV ejection fraction (risk ratio = 1.8), serum total cholesterol (risk ratio = 1.005), and serum high-density lipoprotein cholesterol (risk ratio = 0.96).

Adult↗
PubMed1998

Comparison of frequency of new coronary events in older persons with mild, moderate, and severe valvular aortic stenosis with those without aortic stenosis.

Independent risk factors for new coronary events were prior myocardial infarction, valvular aortic stenosis, male gender, and increasing age in patients with aortic stenosis. In older persons with moderate or severe valvular aortic stenosis, congestive heart failure, syncope, or angina pectoris was present in 101 of 114 persons (89%) with new coronary events and in 1 of 22 persons (5%) without new coronary events (p <0.0001).

Aged↗
PubMed1998

Association of mitral annular calcium with new thromboembolic stroke at 44-month follow-up of 2,148 persons, mean age 81 years.

We investigated in a prospective study of 2,148 persons (mean age 81 years), the association between mitral annular calcium and new thromboembolic stroke at 44-month follow-up. Independent risk factors for new thromboembolic stroke were prior stroke (risk ratio 2.4), mitral annular calcium (risk ratio 2.6), atrial fibrillation (risk ratio 3.0), and male gender (risk ratio 1.6).

Aged↗
PubMed1998

Systemic lupus erythematosus in three ethnic groups: I. The effects of HLA class II, C4, and CR1 alleles, socioeconomic factors, and ethnicity at disease onset. LUMINA Study Group. Lupus in minority populations, nature versus nurture.

OBJECTIVE: To study the relative impact of immunogenetic versus socioeconomic factors on systemic lupus erythematosus (SLE) at disease onset/presentation. METHODS: Medical records regarding SLE onset/ presentation were abstracted on 229 SLE patients who were enrolled in a prospective lupus outcome study. Patients were grouped in equivalent proportions of Caucasians, African Americans, and Hispanics. HLA-DRB1, DQA1, and DQB1 oligotyping, as well as C4 and CR1 allotyping, were carried out by standard methods. In addition to these genetic factors, data on ethnicity, age at SLE onset, monthly income, level of education, and home ownership were entered into stepwise logistic or stepwise multiple linear regression models as independent variables, and each specific clinical feature (neurologic, renal, and cardiovascular disease due to SLE), as well as the total Systemic Lupus Activity Measure (SLAM) score and physician's global assessment of disease activity at disease onset, were entered as dependent variables. RESULTS: HLA-DRB1*0301 (DR3), DRB1*1503 (DR2), and DRB1*08 (DR8) alleles were more frequently found in Caucasians, African Americans, and Hispanics, respectively. Hispanics were more likely to have cardiac and renal disease, as well as a higher physician's global assessment of disease activity. African Americans were more likely to have neurologic disease, renal disease, and a higher SLAM score. Those with less education had a higher SLAM score. Patients with HLA-DRB1*01 had less renal disease and a lower SLAM score. Those with C4A*3 alleles had a higher SLAM score and a higher physician's global assessment of disease activity. CONCLUSION: Both genetic and socioeconomic determinants, as well as other factors associated with Hispanic and African-American ethnicity, affect the presentation of SLE.

Adolescent↗
PubMed1998

Resolving gastroesophageal reflux with laparoscopic fundoplication. Findings in 138 cases.

BACKGROUND: The purpose of this study was to evaluate the results of 138 cases of gastroesophageal reflux disease resolved laparoscopically with the Rossetti modification of the Nissen fundoplication and to compare them with findings from other studies in an effort to evaluate the procedure's ability to transfer from an academic setting to a community hospital setting. METHODS: We performed laparoscopic Nissen fundoplication on 138 patients and followed them for up to 45 months. Measures included postoperative reflux persistence, complications, operating time, length of hospital stay, and others. These findings were compared, using the Fisher's exact test, chi-square test, and the two-sample t-test, with results from other studies using open and laparoscopic procedures. RESULTS: No patient undergoing laparoscopic fundoplication experienced gastroesophageal reflux after surgery. Complications, not statistically significantly different from those in other studies, occurred in 15 (10.9%), and conversion to an open procedure was required in two (1.5%). The most common postoperative complaint has been dysphagia (21.7%). Operative time averaged 70.6 min, decreasing from an average of 236 min for the first 10 cases to 40.8 min for the last 10. This measure was statistically significantly lower than all other operative times to which it was compared, except one to which it was almost identical (69.9 min). Length of stay (LOS) averaged 2.3 days, ranging from a low of 7 h to a high of 9 days, which made it fall well within limits set by other studies. Overall, LOS fell from a 3.0-day average for the first 20 cases to a 1.9-day average for the last 20 cases. CONCLUSIONS: Laparoscopic Nissen fundoplication resolved gastroesophageal reflux in all 138 patients, and measures for complications, operating time, and LOS were well within values reported by other studies, indicating the ability of this procedure to be successfully transferred from academic medical centers to the community hospital setting.

Adolescent↗
PubMed1998

Association between plasma homocysteine and peripheral arterial disease in older persons.

BACKGROUND: Plasma homocysteine is a risk factor for peripheral arterial disease. METHODS: In a cross-sectional study design we investigated the association between plasma homocysteine, vitamin B12 and folate concentrations, and the prevalence of peripheral arterial disease in 158 men and 362 women, mean age 81 +/- 8 years. RESULTS: Univariate analysis showed that plasma homocysteine, vitamin B12 (inverse association) and folate (inverse association) concentrations and increased plasma homocysteine and low or indeterminate vitamin B12 concentrations were risk factors for peripheral arterial disease in older men and women. Stepwise multiple logistic regression analysis showed that significant independent risk factors for peripheral arterial disease were a greater value of plasma homocysteine (P = 0.0001; odds ratio = 1.125) and a low value of plasma folate (P = 0.0001; odds ratio = 0.709). CONCLUSIONS: High plasma concentrations of homocysteine and low plasma concentrations of folate are significant independent risk factors for peripheral arterial disease in older men and women.

Aged↗
PubMed1998

Prevalence of coronary artery disease, atherothrombotic brain infarction, and peripheral arterial disease: associated risk factors in older Hispanics in an academic hospital-based geriatrics practice.

OBJECTIVE: To investigate the prevalence of coronary artery disease (CAD), atherothrombotic brain infarction (ABI), and peripheral arterial disease (PAD) in older Hispanics and the association with risk factors in this population. DESIGN: A retrospective analysis of charts from all Hispanics seen during January 1996 through July 1997 at an academic hospital-based geriatrics practice. SETTING: An academic, hospital-based, primary care geriatrics practice staffed by fellows in a geriatrics training program and by full-time faculty geriatricians. PATIENTS: One hundred sixty women and 53 men, mean age 80 +/- 8 years (range 64 to 100), were included in the study. MEASUREMENTS AND MAIN RESULTS: Of 213 Hispanics in the study, 59 (28%) had documented CAD, 43 (20%) had ABI, 34 (16%) had PAD, and 90 (42%) had either CAD, ABI, or PAD. Serum total cholesterol and triglycerides were measured in 202 of 213 subjects (95%). Serum high-density lipoprotein cholesterol was measured in 137 of 213 patients (64%). Other risk factor data were documented in all patients. Multiple logistic regression analysis performed in 202 patients using the variables age, gender, cigarette smoking, hypertension, diabetes mellitus, obesity, serum total cholesterol, and serum triglycerides showed statistically significant associations between prevalent CAD, ABI, or PAD and age (P = .002, odds ratio (OR) = 1.083), cigarette smoking (P = .002, (OR) = 3.865), hypertension (P = .007, (OR) = 2.749), diabetes mellitus (P = .028, (OR) = 2.386), obesity (P = .014, (OR) = 2.608), serum total cholesterol (P < 0.001, (OR) = 1.025), and serum triglycerides (P = .017, (OR) = .993). CONCLUSIONS: Either CAD, ABI, or PAD was present in 42% of 213 older Hispanics. There were statistically significant associations between prevalent CAD, ABI, or PAD in older Hispanics and risk factors, including age, cigarette smoking, hypertension, diabetes mellitus, obesity, and serum total cholesterol.

Academic Medical Centers↗
PubMed1998

Association of electrocardiographic left ventricular hypertrophy with the incidence of new congestive heart failure.

OBJECTIVE: To investigate the association of electrocardiographic (ECG) left ventricular hypertrophy (LVH) with the incidence of new congestive heart failure (CHF) in older people. DESIGN: In a prospective study of 2638 older people, ECGs were obtained at study entry, at 1 month after study entry, when clinically indicated, and at least yearly after study entry. ECG LVH was diagnosed if the point score of Romhilt and Estes was > or = 5. Persistent LVH was diagnosed if all of the ECGs showed LVH. New LVH was diagnosed if the baseline ECG showed no LVH but LVH was present on the last ECG. Regression of LVH was diagnosed if the baseline ECG showed LVH but no LVH was present on the last ECG. No LVH was diagnosed if all of the ECGs showed no LVH. Persistent LVH, new LVH, regression of LVH, and no LVH were correlated with the incidence of new CHF at follow-up. SETTING: A large long-term health care facility. PATIENTS: The patients included 1805 women and 833 men, mean age 81 +/- 9 years (range 60 to 103). MEASUREMENTS AND MAIN RESULTS: Of the 2,638 older persons studied, 281 (11%) had persistent ECG LVH, 31 (1%) had new ECG LVH, 12 (0.5%) had regression of ECG LVH, and 2314 (88%) had no ECG LVH. At 42 +/- 24 months (range 1 to 154 months) follow-up, new CHF developed in 168 of 281 persons (60%) with persistent LVH, in 16 of 31 persons (52%) with new LVH, in 4 of 12 persons (33%) with regression of LVH, and in 507 of 2314 persons (22%) with no LVH. Kaplan-Meier survival curves showed that the development of new CHF was higher in persons with persistent LVH versus regression of LVH (P = .013), in persons with persistent LVH versus no LVH (P = .001), in persons with new LVH versus regression of LVH (P = .039), and in persons with new LVH versus no LVH (P = .001). CONCLUSION: Older persons with persistent or new ECG LVH have a higher incidence of new CHF and an earlier time to the development of new CHF than older persons without ECG LVH.

Aged↗
PubMed1998

Aortic sinotubular atherosclerotic debris associated with cerebral embolic events can be identified by transthoracic echocardiography.

OBJECTIVE: To evaluate the association between the presence of aortic sinotubular debris (STAD) identified by transthoracic echocardiography (TTE) and embolic strokes. BACKGROUND: The presence of atherosclerotic debris in the ascending aorta or aortic arch detected by transesophageal echocardiography or epiaortic echocardiography has been well established to be correlated with embolic stroke or other thromboembolic events. No data are available on the role of TTE in describing aortic pathology in thromboembolic events. METHODS: We identified 60 transthoracic echocardiographic studies from 11,275 studies, in which STAD was diagnosed. The charts of these patients (group 1; mean age 67 +/- 10 years) were reviewed and compared with those of 57 patients (group 2) without STAD, matched for age, gender and risk factors for advanced atherosclerosis. The results of brain imaging procedures, carotid duplex and coronary angiography were also reviewed. RESULTS: Ischemic stroke was found in 15 of group 1 (25%) and 4 patients of group 2 (7%, odds ratio = 4.4; 95% confidence interval, 1.3-19.4, p = 0.008). The average thickness of STAD was 0.7 +/- 0.2 cm in stroke patients and 0.6 +/- 0.2 cm in patients without stroke (p = n.s.). STAD was associated with </=40% carotid artery stenosis. CONCLUSION: STAD detected by TTE is strongly associated with embolic strokes. Our findings expand the role of TTE in the evaluation of patients with embolic strokes.

Aged↗
PubMed1998

Evaluation of renal tubular functions in convalescent phase of hemorrhagic fever with renal syndrome.

To evaluate renal tubular functions and to investigate the causative factors of urinary-concentrating defects in the late stage of hemorrhagic fever with renal syndrome (HFRS), 11 HFRS patients in the convalescent phase were studied and compared with 8 acute renal failure (ARF) patients in convalescence (disease controls) and 9 healthy adults preparing for kidney donation (normal controls, NC). Minimal urine osmolality induced by water loading was higher (p < 0.05) in HFRS (89.5 +/- 22.1 mosm/kg) and ARF patients (84.8 +/- 14.7 mosm/ kg) than in NC (47.8 +/- 4.6 mosm/kg), but the solute-free water clearance of HFRS patients (9.0 +/- 1.3%), measured at maximal diuresis, was not different from that of ARF patients (6.7 +/- 1.2%) or NC (10.5 +/- 1.4%). After 12-hour water deprivation + vasopressin stimulation, HFRS had lower urine osmolality (433.7 +/- 31.1 versus 850.0 +/- 35.1 mosm/kg; p < 0.05), urine-to-plasma osmolality ratio (1.47 +/- 0.11 versus 2.91 +/- 0.11; p < 0.05), and solute-free water reabsorption (0.53 +/- 0.07 versus 0.91 +/- 0.12%; p < 0.05) than NC. As compared with ARF patients (1.09 +/- 0.16%) or NC (1.49 +/- 0.16%), HFRS patients (0.43 +/- 0.20%) had lower solute-free water reabsorption measured at maximal antidiuresis induced by water deprivation + vasopressin stimulation + hypertonic saline infusion (p < 0.05). In HFRS, the plasma vasopressin level and plasma vasopressin/osmolality ratio increased from 3.9 +/- 0.8 to 6.1 +/- 1.1 pg/ml and from 0.013 +/- 0.003 to 0.020 +/- 0.004 pg/ml/mosm/kg after 12-hour water deprivation, respectively (p < 0.01). However, neither basal nor stimulated values of the plasma vasopressin level or plasma vasopressin/osmolality ratio was different among the 3 groups. HFRS patients were not different from ARF patients or NC in lithium clearance, urinary-acidifying capacity, and fractional excretions of sodium, potassium and bicarbonate. We conclude that in the convalescent phase of HFRS, the urinary-acidifying ability is not disturbed, the urinary-diluting defect is mild, and the urinary-concentrating capacity is obviously impaired. This study suggests that the most important factor contributing to the urinary-concentrating defect in HFRS is the reduced collecting duct responsiveness to vasopressin.

Acute Kidney Injury↗