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Complementary studies of the gastrointestinal safety of the cyclo-oxygenase-2-selective inhibitor etoricoxib
Hunt, R H; Harper, S; Callegari, P; Yu, C; Quan, H; Evans, J; James, C; Bowen, B; Rashid, F
BACKGROUND:Cyclo-oxygenase-2-selective non-steroidal anti-inflammatory drugs are intended to preserve cyclo-oxygenase-1-mediated gastroprotection and platelet function, whilst inhibiting cyclo-oxygenase-2-mediated inflammation. AIM/OBJECTIVE:To assess the gastrointestinal safety of the cyclo-oxygenase-2-selective inhibitor etoricoxib vs. non-selective non-steroidal anti-inflammatory drugs. METHODS:Two randomized, double-blind, placebo- and active-controlled studies were performed: (i) daily faecal red blood cell loss was measured in 62 subjects receiving etoricoxib (120 mg once daily), ibuprofen (800 mg t.d.s.) or placebo for 28 days; (ii) the incidence of endoscopically detectable gastric/duodenal ulcers was determined in 742 osteoarthritis or rheumatoid arthritis patients receiving etoricoxib (120 mg once daily), naproxen (500 mg b.d.) or placebo over 12 weeks. RESULTS:In the first study, the between-treatment ratio of faecal blood loss for etoricoxib vs. placebo (1.06) was not significantly different from unity; however, the ratios for ibuprofen vs. placebo (3.26) and etoricoxib (3.08) were significantly greater than unity (P < 0.001). In the second study, the incidence of ulcers of > or = 3 mm with naproxen (25.3%) was significantly higher than that with etoricoxib (7.4%) or placebo (1.4%; P < 0.001); the results were similar for ulcers of > or = 5 mm. CONCLUSIONS:The reduced toxicity of etoricoxib (less faecal blood loss and fewer endoscopically detectable lesions) suggests that use of this drug will may be associated with a reduced incidence of gastrointestinal perforations, ulcers and bleeds.
PMID: 12534404
ISSN: 0269-2813
CID: 5162692
Variability and lack of predictive ability of asthma end-points in clinical trials
Zhang, J; Yu, C; Holgate, S T; Reiss, T F
While a consensus definition of the clinical parameters important in asthma control exists, an adequate objective definition of a response to asthma treatment and parameters for prediction of that response remain undefined. Given that asthma is a complex biological disease and that different parameters may measure dissimilar aspects of the disease status, this study assessed the relationship among several end-points of asthma control, and attempted to select a combination of variables measured before (baseline characteristics) or early in asthma therapy which would be predictive of a long-term clinical response. Data from two previously reported clinical studies which included montelukast, inhaled beclomethasone, and placebo in mild-to-moderate asthmatics (n=1,576) were analysed. The forced expiratory volume in one second (FEV1), daily symptoms score (DSS), beta-agonist use, and morning peak expiratory flow (PEFAM) were recorded during the baseline period and throughout the 12-week treatment period. For the long-term response, as measured during the last 9 weeks of treatment, there was a large within-patient variability and no more than a moderate correlation between the changes in FEV1 and PEFAM; DSS and FEV1; and DSS and beta-agonist use. The overall predictive values for FEV1 and DSS were 70-80%. The results showed that multiple measurements over a length of time are needed to establish a more complete profile of response, and that demographic and early treatment responses had a small but inadequate ability to predict future response. This study demonstrates the complex relationship among asthma end-points and the difficulty of reliably estimating long-term response using common, surrogate clinical markers of asthma control.
PMID: 12449161
ISSN: 0903-1936
CID: 5162722
Stratified double sampling with continuous outcomes : design and analysis
Davidov, Ori; Yu, Chang
ORIGINAL:0015458
ISSN: 0233-1888
CID: 5162922
Statistical inference for familial disease clusters
Yu, Chang; Zelterman, Daniel
In many epidemiologic studies, the first indication of an environmental or genetic contribution to the disease is the way in which the diseased cases cluster within the same family units. The concept of clustering is contrasted with incidence. We assume that all individuals are exchangeable except for their disease status. This assumption is used to provide an exact test of the initial hypothesis of no familial link with the disease, conditional on the number of diseased cases and the distribution of the sizes of the various family units. New parametric generalizations of binomial sampling models are described to provide measures of the effect size of the disease clustering. We consider models and an example that takes covariates into account. Ascertainment bias is described and the appropriate sampling distribution is demonstrated. Four numerical examples with real data illustrate these methods.
PMID: 12229982
ISSN: 0006-341x
CID: 5161562
Effect of montelukast, a once-daily leukotriene receptor antagonist, on peak expiratory flow variability
Zhang, Ji; Yu, Chang; Noonan, Gertrude; Reiss, Theodore F
BACKGROUND:Peak expiratory flow (PEF) is an important measure of airway functin in asthma. PEF variability (PEFvar) assessment is described in asthma treatment guidelines as another means of evaluating patient status and response to therapy. OBJECTIVE:The goal of this study was to determine the clinical effect of oral montelukast, a leukotriene receptor antagonist, on PEFvar in asthmatic patients and to assess the relationship of PEFvar with other clinical measures. METHODS:This was a retrospective analysis of data from a multicenter, randomized, double-blind, placebo-controlled, parallel-group study, details of which have been published previously. Eligible patients had chronic stable asthma, had a forced expiratory volume in 1 second (FEV1) that was 50% to 85% of the predicted value, used inhaled beta-agonists, had at least 15% improvement in absolute FEV1 after inhaled beta-agonist administration, and showed a minimal predefined level of daytime asthma symptoms. Treatment consisted of a 2-week, single-blind, placebo run-in period followed by a 12-week, double-blind treatment period (montelukast 10 mg or matching placebo once daily at bedtime). RESULTS:Six hundred eighty-one patients (age range, 15-79 years) were randomized to treatment at 50 centers. Baseline PEFvar was 11.44% +/- 6.55% and 10.62% +/- 6.48% in the montelukast and placebo groups, respectively. PEFvar decreased 20.1% and 7.5% from baseline in the montelukast and placebo groups, respectively. The between-group difference was significant (P < 0.001). PEFvar had low correlation with other clinical measures. CONCLUSIONS:Over 12 weeks of treatment, montelukast significantly reduced PEFvar compared with placebo, indicating improved asthma control. The relative reduction in PEFvar was similar in patients with different degrees of variability at baseline. PEFvar did not correlate highly with other outcome variables and may measure different aspects of the disease.
PMID: 12017402
ISSN: 0149-2918
CID: 5162712
Sums of dependent Bernoulli random variables and disease clustering
Yu, C; Zelterman, D
ISI:000176787500008
ISSN: 0167-7152
CID: 5162902
Evaluation of two self-care treatments for prevention of vaginal candidiasis in women with HIV
Williams, A B; Yu, C; Tashima, K; Burgess, J; Danvers, K
Vaginal candidiasis (VC) is a common concern for women living with HIV infection. The authors evaluated the effectiveness of two self-care approaches to prophylaxis of VC among HIV-infected women, weekly intravaginal application of Lactobacillus acidophilus or weekly intravaginal application of clotrimazole tablets, in a randomized, double-blind, placebo-controlled trial. VC was defined as a vaginal swab positive for Candida species in the presence of signs/symptoms of vaginitis and the absence of a diagnosis of Trichomonas vaginalis or bacterial vaginosis. Thirty-four episodes of VC occurred among 164 women followed for a median of 21 months. The relative risk of experiencing an episode of VC was 0.4 (95% CI = 0.2, 0.9) in the clotrimazole arm and 0.5 (95% CI = 0.2, 1.1) in the Lactobacillus acidophilus arm. The estimated median time to first episode VC was longer for clotrimazole (p = .03, log rank test) and Lactobacillus acidophilus (p = .09, log rank test) compared with placebo. Vaginal yeast infections can be prevented with local therapy. Education about self-care for prophylaxis of VC should be offered to HIV-infected women.
PMID: 11486720
ISSN: 1055-3290
CID: 5162672
Analysis of montelukast in mild persistent asthmatic patients with near-normal lung function
Barnes, N; Wei, L X; Reiss, T F; Leff, J A; Shingo, S; Yu, C; Edelman, J M
Few studies have specifically evaluated controller therapy in patients with mild persistent asthma. We used a subgroup analysis to investigate the effects of montelukast, a potent cysteinyl leukotriene receptor antagonist, on adult patients on the milder end of the asthma severity spectrum. We have identified seven double-blind, randomized, placebo-controlled studies of adult patients with mild-to-moderate chronic asthma in which montelukast was investigated. Subsets of patients with baseline forced expiratory volume in 1 sec (FEV1) > 80% and > 75% predicted or further restricted by less than daily rescue beta-agonist use were included as four cohorts (A, B, C, D), and efficacy measures, including change in FEV1 rescue-free days, beta-agonist use, nocturnal awakenings and blood eosinophil counts were evaluated. Cohorts A to D comprised 21%, 8%, 11%, and 4%, respectively, of patients from these studies. Mean pretreatment FEV1 ranged from 81% to 84% predicted and daily beta-agonist use from 2.4 to 4.5 puffs day(-1) in the four cohorts. Pooled results demonstrated a treatment effect for montelukast over placebo in all cohorts, for all endpoints. There was a significant improvement in FEV1 in montelukast-treated patients (7-8% over baseline) compared with placebo (1-4% over baseline, between-group difference P < or = 0.02) for all cohorts. Similarly, the percentage of rescue-free days increased substantially more with montelukast (22-30%) than with placebo (8-13%). This subgroup analysis indicates that montelukast produced improvements in parameters of asthma control in patients with milder persistent asthma that should be confirmed in additional prospective trials.
PMID: 11392579
ISSN: 0954-6111
CID: 5162702
Exact inference for family disease clusters
Yu, C; Zelterman, D
ISI:000172624000005
ISSN: 0361-0926
CID: 5162892
The Braden Scale for pressure ulcer risk: evaluating the predictive validity in Black and Latino/Hispanic elders
Lyder, C H; Yu, C; Emerling, J; Mangat, R; Stevenson, D; Empleo-Frazier, O; McKay, J
The purpose of this study was to examine the predictive validity of the Braden scale in predicting pressure sore risk and to determine the physiological and nonphysiological variables associated with the prediction of pressure ulcers in Black and Latino/Hispanic elders. A prospective clinical design ws used to conduct the study. Among 74 patients aged 60 years or older, 24 patients (32%) developed either a stage 1 or stage 2 pressure ulcer. Black elders had a higher incidence rate (21%) than Latino/Hispanic elders (11%). A 2-tailed Fisher's exact test revealed that the Braden scale with a cutoff score of 18 was highly associated with predicting Black elders aged 75 years and older who were at risk of developing pressure ulcers (p < or = .011). Sensitivity was 81% and specificity was 100%. The female gender was also a highly significant factor in the development of pressure ulcers (chi 2(1, N = 49) = 6.4, p < or = .011). Overall, the Braden scale was found to be a valid tool in predicting pressure ulcer risk in Black elders aged 75 years or older when a cutoff score of 18 is used.
PMID: 10319520
ISSN: 0897-1897
CID: 5162652