Exploring variables for their independent prognostic effect on survival was carried out using the multivariate stepwise Cox's proportional regression hazard model (Cox and Oakes, 1997).
However, using the multivariate stepwise logistic regression, we had a model with good discrimination containing the SOFA score, age, chloride and albumin (area under receiver operating characteristic curve = 0.80; 95% CI = 0.73 to 0.87).
27 SPSS V.18.0 Software SPSSS, Chicago, Illinois, USA) for Windows was used for correlation analysis, and R 2.15.1, free software available at (http://www.r-project.org/), was used to conduct the multivariate stepwise regression (conditional backwards with the Akaike information criterion) on the hospital-level dataset.
Using the stepwise multivariate logistic regression, microscopic hematuria and serum IgA were the only variables statistically linked to IgAN (P < 0.0001 and P = 0.01, resp).
Using a multivariate stepwise logistic regression analysis, two models were tested.
Variables were included one at a time in the multivariate model using the forward stepwise procedure, adding the predictor with the largest score statistic.
In study 1 (discovery analysis), following Motzer et al (1999, 2002) and Heng et al (2009), baseline factors were first individually evaluated for association with OS using a univariate Cox proportional hazards model, and subsequently evaluated using multivariate stepwise model selection (forward selection at P≤0.1 to enter the model and backward selection at P≤0.05 to stay in the model) (Table 2).
Variation in the nearshore data was analyzed using multivariate stepwise regressions with respect to landscape characteristics of the adjacent coastal watersheds (US only).
Using multivariate stepwise linear regression, we assessed the construct validity of the EQ-5D and ICECAP-O using three dependent measures that are recognized indicators of "impaired mobility" – physiological falls risk, general balance and mobility, and cognitive status among older adults.
Variables of significant value from the univariate analyses were entered into multivariate analysis using the backward stepwise Cox regression analysis.
Statistically significant values from COX univariate analyses were entered into a multivariate analysis using the backward stepwise Cox regression model.
