Page 62 - Exploring the Potential of Self-Monitoring Kidney Function After Transplantation - Céline van Lint

60 Chapter 3
sig. F change = 0.06) than Model 1. In other words neither performance expectancy nor trust could explain patients’ behavioural intention beyond affect, which was again the only significant predictor.
The model was examined for possible biases caused by outliers or influential cases. First, the model fit did improve (F(1, 42) = 23.55, p < .001, R2 = 0.36) after removing two outliers with standardized residuals larger than 2.58, which is more than 1% of the sample cases [56]. Secondly, influential cases were examined by calculating Cook’s distance, leverage, and DFBeta. No cases were found having Cook’s distance or standardised DFBeta larger than the recommended upper value of 1 [56]. Still two patients had their leverage value larger than the recommend upper value of 0.13, i.e. 3×(the number of predictors+1)/n [55]. Excluding these two patients resulted in a model with F(1, 42) = 16.13, p < .001, R2 = 0.28. The original model therefore seems stable and not influenced by possible outliers or influential cases.
Correlation with Exogenous Variables
The constructs affect and behavioural intention were future explore by examining correlations with patient characteristics, i.e. age, gender, donor type, educational level, the number of kidney transplants, being dialyses before transplant, and PIH - knowledge dimension. The analyses were done on paired complete cases. The analyses revealed that deceased, compared to living donor recipients, were associated with a higher Affect level, rpb = .29, 95% CI[.16, .47], n = 42. Furthermore compared to patients that did not receive dialyses before transplant, patients that did were associated with a higher Affect level, rpb = .34, 95% CI[.07, .55], n = 42. The analysis also revealed that female, compared to male patients, were associated with a stronger behavioural intention at T1, rpb = .33, 95% CI[.16, .51], n = 45. No other significant correlations were found.