Home About us Contact
|
Home About us Contact | ||
|
|
||
Altman Method (altman + method)
Selected AbstractsTBI or not TBI: that is the question.DIABETIC MEDICINE, Issue 7 2001Is it better to measure toe pressure than ankle pressure in diabetic patients? Abstract Aims Measurement of ankle blood pressure is a simple method of assessing lower limb arterial blood supply. However, its use in diabetes has been questioned due to the presence of medial artery calcification. Measurement of toe blood pressure has been advocated as an alternative but it is technically more difficult. The aim of this study was to obtain information to guide clinicians as to when pressure measurements should be taken at the toe. Methods Ankle brachial index (ABI) and toe brachial index (TBI) were measured by Doppler ultrasound, or photoplethysmography on 174 subjects with diabetes and 53 control subjects. The Bland and Altman method, and the Cohen's method of measuring agreement between two tests were used to compare ABI with TBI. Results The mean differences between ABI and TBI in control and diabetic subjects are 0.40 ± 0.13 and 0.37 ± 0.15, respectively. Nearly all diabetic patients with an ABI <,1.3 have an ABI,TBI gradient falling within the normal range established from the non-diabetic cohort. In contrast, the majority of diabetic subjects with an ABI ,,1.3 have ABI,TBI differences outside this range. When patients are categorized according to ABI and TBI, there is also good agreement between the tests when ABI is low or normal (84% and 78% agreement, respectively), but not when ABI is elevated. Conclusion In the majority of patients with diabetes, assessment of TBI conveys no advantage over ABI in determining perfusion pressure of the lower limbs. Only in those patients with overt calcification, which gives an ABI ,,1.3, are toe pressure measurements superior. This guideline should simplify assessment and treatment of diabetic patients with disease of the lower limbs. Diabet. Med. 18, 528,532 (2001) [source] Diagnosis of peripheral arterial disease in general practice: can the ankle,brachial index be measured either by pulse palpation or an automatic blood pressure device?,INTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 7 2008V. Aboyans Summary Background:, Despite its validity as a screening test for peripheral arterial disease (PAD), and its prognostic value, the ankle,brachial index (ABI) is infrequently used in primary care, probably because a Doppler device is required, along with the requisite skill for its use. We hypothesized that ABI could be accurately measured either by pulse palpation (pABI) or automatic blood pressure devices (autoABI) instead of Doppler method (dABI). Design and methods:, In 54 subjects, we compared the results and the intra-observer reproducibility of pABI to dABI, as well as the inter-observer reproducibility of both pABI and autoABI to dABI. Arm and ankle systolic pressures were measured by the three methods by two observers. The first observer repeated pABI and dABI measurements. The results were compared by the Student paired t -test. Reproducibility was assessed by the intra-class correlation coefficient of agreement (R) and the Bland and Altman method. Results:, The mean dABI obtained by the first observers was 1.03 ± 0.26 vs. a pABI of 0.85 ± 0.44 (p < 0.0001) and an autoABI of 1.09 ± 0.31 (p < 0.05). The intra-observer R -coefficient was at 0.89 for dABI vs. 0.60 for pABI (p < 0.05). The inter-observer R -coefficients were 0.79 for dABI vs. 0.40 for pABI (p < 0.05) and 0.44 for autoABI (p < 0.05). Conclusion:, Neither pulse palpation nor automatic oscillometric devices can be recommended as reliable methods for ABI measurement. [source] Assessing Levels of Agreement between Two Commonly Used Oral Health-Related Quality of Life MeasuresJOURNAL OF PUBLIC HEALTH DENTISTRY, Issue 3 2009Eduardo Bernabé MSc Abstract Objective: This study aimed to assess the level of agreement between two commonly used oral health-related quality of life (OHRQoL) measures, the short form of the Oral Health Impact Profile (OHIP14) and the Oral Impacts on Daily Performances (OIDP). Methods: A sample of 1,675 15- to 16-year-old students attending all schools in Bauru (Sao Paulo, Brazil) was selected. The impact of oral conditions on quality of life in the last 6 months was reported using both OHIP14 and OIDP. To allow for comparison with the 100 percent OIDP score, OHIP14 scores were converted to percentages. Then, agreement between the two OHRQoL measures was analyzed using the Bland and Altman method. Results: The mean difference between OHIP14 and OIDP was 6.48 percent [confidence interval95% (6.08; 6.89)], with higher scores reported for OHIP14 than for OIDP. Besides, 95 percent of the differences between the two OHRQoL measures were between ,10.59 and 23.56 percent. Finally, differences between OHIP14 and OIDP increased significantly as the magnitude of their average increased (P < 0.001). Conclusion: There was a moderate level of agreement between OHIP14 and OIDP, which may be partly due to the fact that both OHRQoL measures assess different levels of oral impacts on quality of life in addition to having different scoring systems. [source] Evaluation of statistical protocols for quality control of ecosystem carbon dioxide fluxesJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 1 2007Jorge F. Perez-Quezada Summary., The process of quality control of micrometeorological and carbon dioxide (CO2) flux data can be subjective and may lack repeatability, which would undermine the results of many studies. Multivariate statistical methods and time series analysis were used together and independently to detect and replace outliers in CO2 flux data derived from a Bowen ratio energy balance system. The results were compared with those produced by five experts who applied the current and potentially subjective protocol. All protocols were tested on the same set of three 5-day periods, when measurements were conducted in an abandoned agricultural field. The concordance of the protocols was evaluated by using the experts' opinion (mean ± 1.96 standard deviations) as a reference interval (the Bland,Altman method). Analysing the 15 days together, the statistical protocol that combined multivariate distance, multiple linear regression and time series analysis showed a concordance of 93% on a 20-min flux basis and 87% on a daily basis (only 2 days fell outside the reference interval), and the overall flux differed only by 1.7% (3.2 g CO2 m,2). An automated version of this or a similar statistical protocol could be used as a standard way of filling gaps and processing data from Bowen ratio energy balance and other techniques (e.g. eddy covariance). This would enforce objectivity in comparisons of CO2 flux data that are generated by different research groups and streamline the protocols for quality control. [source] Comparison of Four Staining Methods for Detection of Mast Cells in Equine Bronchoalveolar Lavage FluidJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 2 2006Mathilde Leclere Mast cells normally are present in equine bronchoalveolar lavage fluid (BALF), but usually represent <2% of all cells in healthy horses. An increased percentage of mast cells has been associated with airway hyperactivity and inflammatory airway diseases, but marked differences are reported between studies in normal and diseased horses. Because an abnormal mast cell count may be of clinical relevance, we compared the ability of a fast Romanowsky method to stain mast cell granules with that of 3 metachromatic stains: automated Romanowsky, May-Grünwald Giemsa, and toluidine blue stains. The BALF cells from 24 horses were studied. A differential cell count was performed blindly on 400 cells. The percentages of mast cells obtained were analyzed by means of repeated-measures analysis of variance and Fischer's PLSD test. The Bland and Altman method was used to assess agreement among stains. The mean percentage of mast cells in BALF was significantly lower with the fast Romanowsky than with the automated Romanowsky, May-Grünwald Giemsa, and toluidine blue stains. With the fast Romanowsky stain, the metachromatic granules of mast cells were not stained, and their identification was based on morphologic criteria. Toluidine blue staining allowed detection of the highest mean percentage of mast cells, but was inadequate for performing a differential cell count on other cell types. In conclusion, fast Romanosky stain may be inadequate for detection of mast cells in equine BALF, whereas automated Romanowsky, May-Grünwald Giemsa, and toluidine blue stains provide metachromatic staining of mast cell granules. [source] The six-minute walk test in outpatients with obesity: reproducibility and known group validityPHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 2 2008Ulla Evers Larsson Abstract Background and Purpose.,To assess the reproducibility and validity of the six-minute walk test (6MWT) in men and women with obesity in order to facilitate evaluation of treatment outcome.,Method.,A test,retest design was used to test reproducibility and a comparative design to test known group validity. Forty-three obese outpatients (16 male), mean age 47 (21,62) years, mean body mass index (BMI) 40 (3,62)kg-m,2 performed the 6MWT twice within one week. Intraclass correlation (ICC1.1) and measurement error (Sw) were calculated from the mean square values derived from a one-way repeated-measures ANOVA (fixed effect model). The reproducibility was also analysed by means of coefficient of variation (CV) and the Bland Altman method including 95% limits of agreement. The variance of the distance walked was analysed by means of regressions. The known group validity of the 6MWT (distance walked and the work of walking) in obese participants was shown by comparisons with 41 lean participants (18 male), mean age 47 (24,65) years, mean BMI 22.7kg-m,2 (19,25).,Results.,The obese group walked 534,m (confidence interval [CI] 508,560 the first and 552,m (CI 523,580) the second walk (p < 0.001). Sw was 25,m, CV 4.7%, ICC1.1 was 0.96. The limits of agreement were ,46,m+80,m. The validity tests showed that they walked 162,m shorter (p < 0.001) and performed much heavier work (p < 0.001) than the lean group. In the obese group, BMI alone explained 38% of the variance of the distance walked.,Conclusions.,The 6MWT showed good reproducibility and known group validity and can be recommended for evaluating walking ability in subjects with obesity. For individual evaluation, however, an improved walking distance of at least 80,m was required to make the difference clinically significant. Despite shorter walking distance the obese participants performed heavier work than the lean. Copyright © 2008 John Wiley & Sons, Ltd. [source] Comparisons between Pascal dynamic contour tonometry, the TonoPen, and Goldmann applanation tonometry in patients with glaucomaACTA OPHTHALMOLOGICA, Issue 3 2007Maria L. Salvetat Abstract. Purpose:, To compare intraocular pressure (IOP) measurements taken with Pascal dynamic contour tonometry (DCT), the TonoPen and the Goldmann applanation tonometry (GAT). The influence of central corneal thickness (CCT) on IOP measurements taken with Pascal DCT and the TonoPen was evaluated. Methods:, One eye in each of 101 consecutive patients with primary open-angle glaucoma (POAG) underwent ultrasonic CCT measurement and IOP evaluation with GAT, Pascal DCT and the TonoPen in random order. The agreement between results from Pascal DCT and the TonoPen and those of GAT was assessed using the Bland,Altman method. The deviation of Pascal DCT and TonoPen readings from GAT values, corrected for CCT, was calculated and correlated to CCT using a linear regression model. Results:, The mean of the differences in IOP measurements was 3.2 ± 2.4 mmHg for Pascal DCT minus GAT readings and 0.5 ± 4.5 mmHg for TonoPen minus GAT readings. The 95% confidence interval of differences in IOP measurements was higher between TonoPen and GAT readings (, 6 to 7 mmHg) than between Pascal and GAT readings (0.1,6.8 mmHg). Pascal DCT significantly overestimated IOP compared with GAT, especially for higher IOP readings. Bland,Altman scatterplots showed reasonable inter-method agreement between Pascal DCT and GAT measurements, and poor agreement between TonoPen and GAT measurements. The deviations of Pascal DCT and TonoPen readings from the corrected GAT values were both highly correlated with CCT values (linear regression analysis, p < 0.0001). The mean change in measured IOP for a 10-µm increase in CCT was 0.48 mmHg for Pascal DCT and 0.74 mmHg for the TonoPen. Conclusions:, Agreement with GAT measurements was higher for Pascal DCT than for TonoPen readings; however, Pascal DCT significantly overestimated IOP values compared with GAT. Measurements of IOP obtained with both Pascal DCT and the TonoPen appeared to be influenced by CCT, and this influence appeared to be greater for the latter. [source] | ||||||||||