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PubMed1998

Measurement of overinflation by multiple linear regression analysis in patients with acute lung injury.

Strategies to optimize alveolar recruitment and prevent lung overinflation are central to ventilatory management of patients with acute lung injury (ALI). The recent description of overinflation using multilinear regression analysis of airway pressure (Paw) and flow (V') data allows a functional assessment of lung mechanics. However, this technique has not been studied in ALI patients. During 15 positive end-expiratory pressure (PEEP) trials in 10 ALI patients, respiratory elastance was partitioned into volume-independent (E1) and volume-dependent (E2VT) components, where Paw=(E1+E2VT)V+RrsV'+Po; where V is volume, VT is tidal volume, Rrs is respiratory resistance and Po is static recoil pressure at end-expiration (equivalent to total PEEP). Then, %E2 was calculated as (100E2VT)/(E1+E2VT); a measure of lung overinflation when %E2>30%. Alveolar recruitment, assessed as a PEEP-induced increase in V>50 mL at a constant Paw occurred in 14 of 15 trials (299+/-34 mL, mean+/-SEM), but was independent of the degree of lung inflation. Lung overinflation was common (six of 15 clinically set PEEP levels) and occurred despite a dynamic elastic distending pressure (Pel,dyn) <30 cmH2O during 18 of 36 PEEP titrations. During a PEEP titration the resultant %E2 was directly related to delta(peak airway pressure-Po) (rs=0.86, p<0.001) and delta(Pel,dyn-Po) (rs=0.89, p<0.001). The 95% predictive intervals for a 2 cmH2O change in either driving pressure were %E2 values of 30.4-68.1% and 32.8-69.2%, respectively. Single or continuous measurement of %E2 (a measure of lung inflation) is a readily available method for titrating ventilatory parameters. Further, during a positive end-expiratory pressure titration a change in ventilatory driving pressure > or =2 cmH2O is indicative of overinflation.

Acute Disease↗
PubMed2003

[Cox regression analysis of predictive factors of hepatorenal syndrome].

OBJECTIVE: To investigate the predictive factors and the best prognostic parameter of hepatorenal syndrome (HRS). METHODS: 71 patients with cirrhosis who underwent HRS were included for multivariate Cox regression analysis. 35 possible predictive factors that included clinical and biochemical features contributing to the survival of these patients were analyzed. RESULTS: Only Child-Pugh's score at the time of diagnosis was the only dependent risk factor of HRS, RR=1.333, 95% CI (1.026, 1.731). CONCLUSION: Child-Pugh's score at the time of diagnosis of HRS is the best parameter for predicting the clinical outcome of HRS.

Adult↗
PubMed2005

Clinical evaluation of the temporomandibular joint following orthognathic surgery--multiple logistic regression analysis.

This study compares temporomandibular joint dysfunction (TMD) symptoms before and after bilateral sagittal split ramus osteotomy, and identifies predictive factors for the postoperative TMD symptoms by assessing the adjusted odds ratio using multiple logistic regression analysis. A consecutive series of 37 cases treated only with bilateral sagittal split ramus osteotomy were evaluated. New postoperative TMD symptoms appeared in 9 cases, preoperative TMD symptoms disappeared in 6 cases, and TMD symptoms were unchanged in 5 cases. The median period until the interincisal opening range attained 40 mm was 5 months (range, from 2 to 15 months). Age was a positive factor in patients with postoperative TMD symptoms, with an odds ratio of 1.43 (95 percent confidence interval, from 1.05 to 1.93). In addition, the maximum value of the bilateral setback distance of more than 9 mm was a positive factor of 6.95 (95 percent confidence interval, from 1.06 to 45.42). We concluded that surgical correction in skeletal malocclusion may affect temporomandibular joint dysfunction symptoms.

Adult↗
PubMed2006

Comparison of the vibration mode of metals in HNO3 by a partial least-squares regression analysis of near-infrared spectra.

The near-infrared (NIR) spectra of such metals as Cu(II), Mn(II), Zn(II) and Fe(III) in HNO(3) in the 700-1,860 nm region were subjected to a partial least-squares regression analysis and leave-out cross-validation to develop chemometric models. The models yielded a coefficient of determination in cross validation of 0.9744 [Cu(II)], 0.9631 [Mn(II)], 0.9154 [Zn(II)] and 0.741 [Fe(III)]. The regression coefficients for Cu(II), Mn(II) and Zn(II), but not for Fe(III), showed strong negative peaks at around 1,050-1,200 nm, a zone where spectral bands have been reported to decrease with increasing pH value. A positive peak at around 710-750 nm, which may have been due to water absorption, was observed in regression coefficients of Cu(II), Mn(II) and Zn(II) but not in Fe(III), while a negative peak was observed in that for Fe(III) at around 710-750 nm. These results indicate that the divalent cations [Cu(II), Mn(II) and Zn(II)] showed different absorption in the NIR region from the trivalent cation [Fe(III)], suggesting that the vibration mode of water, which mirrors the interaction between cations and water, may be influenced by valency.

Cations↗
PubMed1998

Comparing a mass-balance algorithm with a Bayesian regression analysis computer program for predicting serum phenytoin concentrations.

The ability of a mass-balance algorithm to predict non-steady-state phenytoin concentrations in neurosurgery patients was compared with that of Phenda, a computerized Bayesian regression analysis program. Fifty neurosurgery patients who had had two or more initial phenytoin serum concentrations measured at least 60 hours apart and at least 1 hour after any i.v. doses, with the second concentration being not more than twice and not less than half of the first, and who had had a third or final phenytoin measurement (for use in a prediction analysis) were evaluated. The patients' maximum rates of metabolism were calculated by using the two initial phenytoin concentrations and a mass-balance algorithm, and the third phenytoin concentration was predicted. The patients' demographics and phenytoin dosages and concentrations were entered into Phenda, which was used to predict the third phenytoin concentration. The ability of the two methods to predict the third concentration was evaluated by the method of Sheiner and Beal. Fifty observations from 48 patients were evaluated. The mass-balance algorithm had a positive prediction bias of 2.52 mg/L and a precision error of 5.08 mg/L, compared with 2.30 and 5.30, respectively, for Phenda. The difference in the results between the two methods was not significant. There was no significant difference between the mass-balance algorithm and Phenda in the ability to predict phenytoin concentrations.

Algorithms↗
PubMed1996

[Non-conditional logistic regression analysis of affecting factors in patients with NIDDM].

According to the data of investigation, country from the southern part of Jiangsu Province, we analyzed 88 patients with non-insulindependent diabetes mellitus (NIDDM) through a case-control study. Simple and multiple logistic regression analysis demonstrated that the rates of history of hypertension, history of cardiovascular diseases, over nutrition or obesity in patients with NIDDM were significantly higher than those in controls (P < 0.01):OR of hypertension was 4.50, and it was still 2.94 when excluding other factors. These results indicated that hypertension might serve as one of the independent predicting factors. The model of multiple factors non-conditional logistic regression sholwed that NIDDM directly effected on the development of cardiovascular disease.

Adult↗
PubMed1991

[Logistic regression analysis of risk factors of glaucomatous visual field defects].

30 patients (42 eyes) of early primary glaucoma with normal visual field were followed up for 2.5 years, during which time visual field defects developed in 24 eyes. Multivariate logistic regression analysis of the initial values of suspected risk factors demonstrated that a positive family history, the vertical C/D ratio, and the diurnal peak IOP were significant in predicting impending visual field defects.

Follow-Up Studies↗
PubMed2003

Lower-extremity muscle forces measured by a hand-held dynamometer and the risk of falls among day-care users in Japan: using multinomial logistic regression analysis.

PURPOSE: To assess the relationship between the lower extremity muscle forces and risk of falls among the elderly who were using day-care services in the long-term care insurance system. METHOD: The study population comprised 96 women aged 69 - 91 years. At baseline, we assessed ADL, functional capacity, isometric muscle forces of knee extension and ankle dorsiflexion obtained with a hand-held dynamometer. After 1 year, we asked subjects about falls during the follow up period. RESULTS: In univariate analysis, only the knee extensor strength (p = 0.003) and ankle dorsiflexor strength (p = 0.02) differed significantly according to the fall status. After adjustment for age using multinomial logistic regression analysis, the weak quadriceps group was 7.50 times more likely than the strong group to fall once (p = 0.02), and 5.00 times more likely to fall twice or more (p = 0.02). The weakest ankle dorsiflexor group was 5.09 times more likely than the strongest group to fall twice or more (p = 0.05). CONCLUSIONS: Our results indicated that the forces of knee extensor and ankle dorsiflexor were strongly associated with falls among day-care users. Physiotherapy should focus on the lower-extremity muscle strength to prevent falls and deterioration of physical ability among elderly persons who are partially dependent and need support.

Accidental Falls↗
PubMed1996

QT interval-heart rate relation during exercise in normal men and women: definition by linear regression analysis.

OBJECTIVES: This study sought to develop a regression-based method for characterization of QT interval behavior during exercise and to define the normal range of the resulting "dynamic" measures of repolarization during submaximal treadmill testing in men and women. BACKGROUND: The Bazett-corrected QT (QTc) interval during exercise has been used as a marker for ischemic disease, arrhythmogenic substrate and the long QT syndrome. However, recent studies indicate that the QTc interval is nonlinear with respect to heart rate during exercise, making the end-exercise QTc interval dependent on peak work load achieved. In contrast, the unadjusted QT interval measured from QRS onset to T wave offset (QTo) and from QRS onset to T wave peak (QTm) appears to vary linearly with heart rate during gently graded effort. METHODS: The QT interval relation to heart rate and cycle length was examined by linear regression in 50 normal men (mean age 48 years) and 30 normal women (mean age 51 years), all of whom had normal rest electrocardiograms. The QTo and QTm measurements were made from digitized lead V5 complexes averaged by computer over 20-s periods, at upright control and after seven 2-min stages of the Cornell modification of the Bruce treadmill protocol (work load equivalent to Bruce stage 3). RESULTS: For each subject, regression of QTo (ms) versus heart rate (beats/min) resulted in a slope (reflecting the "dynamic" change in QTo during effort), an adjusted intercept (reflecting QTo extrapolated to a heart rate of 60 beats/min) and a significant correlation coefficient (r) value. Under these conditions, mean +/- SD (5th to 95th percentile) values for men were -1.45 +/- 0.34 ms/beat per min (-0.90, "less dynamic" to -1.96, "more dynamic") for the slope; 403 +/- 21 ms (365 to 431) for the adjusted intercept; and -0.93 +/- 0.06 (-0.81 to -0.99) for r. Values for women were more dynamic, with a mean slope of -1.74 +/- 0.32 ms/beat per min (-1.23 to -2.18, p < 0.0005 vs. men) and higher adjusted intercept of 426 +/- 23 ms (392 to 462, p < 0.0001 vs. men) at similar strength of correlation (r = -0.95 +/- 0.06). Corresponding normal data were also tabulated for QTm behavior and QT-RR interval behavior during exercise. CONCLUSIONS: These data provide a "dynamic" definition of normal and abnormal repolarization and describe normal limits for the linear relations of the QTo and QTm intervals with respect to heart rate and cycle length during submaximal exercise in normal men and women.

Electrocardiography↗
PubMed2006

Estimation of nutrient requirements using broken-line regression analysis.

We evaluated and compared various broken-line regression models and SAS (SAS Inst. Inc., Cary, NC) procedures for estimating nutrient requirements from nutrient dose response data. We used the SAS (Version 9) procedures NLIN and NLMixed and the response data of Parr et al. (2003), who evaluated the isoleucine requirement of growing swine. The SAS NLIN was used to fit 2 different broken-line regression models: a simple 2 straight-line, one-breakpoint model and a quadratic broken-line model in which the response below the single breakpoint was quadratic; there was a plateau above the breakpoint. The latter was fit using 2 different approaches in NLIN. We also used SAS NLMixed to fit 3 different broken-line models: the 2 straight-line, one-breakpoint model that included a random component for the plateau; the quadratic broken-line model that included a random component for the plateau; and the quadratic broken-line model that included random components for both the plateau and the slope of the curve below the requirement. The best fit (greater adjusted R2; least log likelihood) was achieved using SAS NLMixed and the quadratic model with a random component for asymptote included in the model. Model descriptions, SAS code, and output are presented and discussed. Additionally, we provide other examples of possible models and discuss approaches to handling difficult-to-fit data.

Algorithms↗
PubMed1982

Regression analysis of matched case-control data.

A regression methodology is outlined for the logistic analysis of matched pair case-control data. This weighted least squares technique is applicable to the problem of analyzing multiple, but categorical, risk factors. Estimates of odds ratios and statistics for hypothesis testing are directly produced with the procedure. The proposed methodology may be viewed as an alternative to that described by Holford et al. (Am J Epidemiol 1978;107:245-56). The required computations may be performed with standard programs for least squares categorical data analysis.

Accidents, Traffic↗
PubMed1993

Harmonic regression analysis of the effect of drug treatment on the diurnal rhythm of blood pressure and angina.

Harmonic regression is a method for analysis of diurnal rhythms which we apply to blood pressure and angina attack rate. We show that population amplitude and phase as previously defined are not the expected values of amplitude and phase in the population unless patients are in phase and that the estimates of these population parameters are the amplitude and phase of the mean measurements of the observation times. We show that the amplitude of the mean measurements underestimates the magnitude of the diurnal rhythm of individual patients due to significant differences among patients in the phase parameter. Thus, the mean of the individual-patient amplitudes and phases, rather than the amplitude and phase of the mean measurements, is necessary to describe the diurnal rhythm in the population and to assess the effect of drug treatment. Harmonic regression analysis yields specific hypotheses that relate directly to the consistency of drug effect over 24 hours.

Amlodipine↗
PubMed2000

Clinical evaluation of idiopathic interstitial pneumonia and interstitial pneumonia associated with collagen vascular disease using logistic regression analysis.

OBJECTIVE: To clarify the differences in the clinical features between idiopathic interstitial pneumonia (IIP) and interstitial pneumonia associated with collagen vascular diseases (CVD-IP). METHODS: Symptoms, radiographic findings, pulmonary function, blood chemistry data including autoantibody, and bronchoalveolar lavage fluid (BALF) findings were compared using multiple logistic regression analysis. PATIENTS: The subjects were 44 patients clinically diagnosed with IIP and 33 patients with CVD-IP. RESULTS: The clinical features related to IIP were as follows: male sex, advanced age, past history of hypertension, presence of cough, exertional dyspnea, digital clubbing, an increased level of gamma-globulin, decreased lung volume on chest X-ray, and typical type according to the criteria for IIP on chest X-ray. Increased levels of rheumatoid factor and total cell number in BALF were related to CVD-IP. CONCLUSION: These findings are considered to be useful to differentiate IIP and CVD-IP.

Adult↗
PubMed2001

Multiple logistic regression analysis of risk factors for the development of steroid-dependent asthma in the elderly: a comparison with younger asthmatics.

BACKGROUND: The percentage of the aged among all patients with bronchial asthma is increasing. OBJECTIVE: To investigate the risk factors for the development of steroid-dependent asthma in the elderly. METHODS: A multiple logistic regression analysis involving various clinical factors between steroid-dependent and -independent asthma was carried out for 59 asthmatics aged over 60 years, including 16 patients with steroid-dependent asthma. The calculated risk for each factor was compared with that obtained from 122 younger asthmatics aged 20-59 years. RESULTS: Among the factors examined (sex, age, period from onset of asthma, type of asthma and family history of asthma, plus history of smoking, atopic dermatitis, allergic rhinitis, chronic sinusitis and nasal polyps), the significant risk factors for the development of steroid dependency in the elderly asthmatics were only family history of bronchial asthma (relative risk 3.6) and smoking history (relative risk 6.9). CONCLUSIONS: Some risk factors for steroid-dependent asthma in younger individuals were not significant in the elderly. Since the smoking history was most closely associated with the development of steroid dependency in the elderly, even though most of them had quit smoking, it is important for patients with asthma to avoid smoking.

Adult↗
PubMed2006

Evaluation of magnetic resonance imaging criteria for cavernous sinus invasion in patients with pituitary adenomas: logistic regression analysis and correlation with surgical findings.

BACKGROUND: This study used high-resolution magnetic resonance (MR) imaging (1.5 T) to define and evaluate preoperative imaging criteria for cavernous sinus invasion (CSI) by pituitary adenoma (PA). METHODS: Magnetic resonance images obtained from 103 patients with PA submitted to surgery (48 with CSI) were retrospectively reviewed. The following MR signs were studied and compared with intraoperative findings: (1) presence of normal pituitary gland between the adenoma and cavernous sinus (CS), (2) status of the CS venous compartments, (3) CS size, (4) CS lateral wall bulging, (5) displacement of the intracavernous internal carotid artery (ICA) by adenoma, (6) grade of parasellar extension (Knosp-Steiner classification), and (7) percentage of intracavernous ICA encased by the tumor. Statistical analysis was performed using chi2 testing, and sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were obtained for each MR finding. The odds ratio of the most significant criteria was also obtained, and the multiple logistic regression test was used to compare the criteria altogether. RESULTS: The following signs have been found to represent accurate criteria for noninvasion of the CS: (1) normal pituitary gland interposed between the adenoma and the CS (PPV, 100.0%), (2) intact medial venous compartment (PPV, 100.0%), and (3) percentage of encasement of the intracavernous ICA lower than 25% (NPV, 100.0%). Cavernous sinus invasion was certain if the percentage of encasement of the intracavernous ICA was higher than 45% and 3 or more CS venous compartments were not depicted. The most valuable criterion of CSI by logistic regression analysis was the percentage of encasement of intracavernous ICA of 30% or more, with an odds ratio of 49.25. CONCLUSION: The preoperative diagnosis of CSI by PA is extremely important because endocrinologic remission is rarely obtained after microsurgery alone in patients with invasive tumors. The aforementioned MR imaging criteria may be useful in patient's management and in advising most of the patients preoperatively on the potential need for complimentary therapy after surgery.

Adenoma↗
PubMed2001

[Logistic regression analysis of wedge-shaped defects in the middle-aged and elderly].

OBJECTIVE: To investigate and identify the possible clinical risk factors associated with the formation of wedge-shaped defects. METHODS: Four hundred and ninety-three subjects were examined. The possible risk factors associated with wedge-shaped defects were identified by logistic regression analysis. RESULTS: The prevalence of wedge-shaped defects was observed 90.5% in this population. The prevalence and severity of wedge-shaped defects were found to be increasing with age. The correlation between age, sex, preferred side for tooth chewing, brushing twice a day, malocclusion, the formation and severity of wedge-shaped defects were noted. CONCLUSION: Occlusal factors and tooth brushing have found related to the formation of wedge-shaped defects.

Age Factors↗
PubMed2003

A randomized double blind, placebo controlled trial of topical Tripterygium wilfordii in rheumatoid arthritis: reanalysis using logistic regression analysis.

OBJECTIVE: To assess the efficacy of topical Tripterygium wilfordii (TW), a Chinese herbal therapy, in rheumatoid arthritis (RA). METHODS: A 6 week randomized double blind placebo controlled study of 61 patients with RA meeting American College of Rheumatology (ACR) criteria was conducted in China. The primary outcome was a modified ACR-20 response rate, analyzed by logistic regression analysis. RESULTS: The modified ACR-20 response rate differed significantly (topical TW 58% vs placebo 20%; p = 0.002). There was an 8.1-fold (95% CI 1.9-35.4) increase in the modified ACR-20 response for the TW compared to the placebo group, adjusted for age and erythrocyte sedimentation rate. CONCLUSION: Topical TW appears efficacious for the treatment of RA, but larger studies are needed.

Adult↗