In preliminary testing, respondents completed the
battery of tests in less than 15 minutes. At baseline the research assistant administer the questionnaire with the use of visual aids to help with answering the questions. When obtaining the consent, patients will be informed of the follow up survey and the same research assistant will contact the patients at six months. This will help in establishing a rapport and increasing the response rate at follow-up. The average retention rate for the surveys conducted by the QOL research team at our institution is in excess of 80%. Quality control and data management Inhibitors,research,lifescience,medical LIPS study collects a large number of data regarding patient exposures and outcomes. To reduce measurement error, a comprehensive data quality assurance program will be employed. Data Inhibitors,research,lifescience,medical will be maintained on a secure server with nightly back up. Single Mayo logon LAN ID (local area network identification) provides access to the data to authorized individuals. Electronic range checks and validation rules will Inhibitors,research,lifescience,medical eliminate erroneous data entry and artifacts in numeric values. As an independent quality control measure periodic audits of the database will be performed. Routine descriptive statistics will be
obtained at regular intervals to assure completeness of data collection. Statistical Analysis An estimate for the probability of ALI development will be calculated for each patient based on the LIPS model. Because of subjective nature of clinical definitions used to identify the outcome of our study, it is necessary to assess interobserver variability. Interobserver agreement for ALI development will be assessed by calculating the Kappa statistic, Inhibitors,research,lifescience,medical using a threshold of 0.6 as an indication of acceptable interobserver agreement.
The calibration and discrimination of model will be assessed using the Hosmer-Lemeshow Inhibitors,research,lifescience,medical goodness-of-fit test and the receiver operating characteristic curve, respectively. An area under the ROC curve greater than 80% will be considered to be the evidence of good model discrimination. Using a LIPS cutpoint of 3.5 or more identified in the preliminary data, the comparison of the model prediction versus the actual event observed will be summarized by a simple 2 by 2 table reporting ALI Selleckchem ABT-888 propensity versus ALI development. Summary measures, based on the L-NAME HCl 2 by 2 table, will be reported: sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratios along with their 95% confidence intervals. In a matched case-control design the associations suggested by preliminary clinical studies (Table (Table3)3) will be compared between ALI cases and high risk controls propensity matched by age, gender and the probability of ALI development at the time of hospital admission (LIPS, see above).