With ic and cli data analysis was performed for

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Unformatted text preview: is was performed for overall comparisons using the statistical package SPSS 11.0 and a P value of <.05 was taken as statistically significant. Procedure The patients were asked by the head nurse to fill out the NHP and the SF-36 questionnaire during their admission before treatment. At the one-year follow-up, the questionnaire was sent home to the patients with a covering letter and a prepaid envelope. The Ethics Committee of Lund University approved the study (LU 470-98, Gbg M 09898). Results Statistical analysis Differences in characteristics between patients with IC and with CLI before revascularization were analysed using Chi-squared test and Mann-Whitney U-test. The prevalence of the lowest ("floor" effect) and highest ("ceiling" effect) possible quality of life score in NHP and SF-36 was also calculated. Construct validity was evaluated for aspects of convergent and discriminant validity by the Multitrait-Multimethod matrix (MTMM) [13] based on five comparable domains, including pain, physical mobility, emotional reactions, energy and social isolation for the NHP and bodily pain, physical functioning, mental health, vitality and social functioning for the SF-36 (Table 2). Further, the MannWhitney U-test was used to examine the relative ability of the two instruments to discriminate among the degrees of severity of the peripheral vascular disease. Spearman's rank correlation coefficient was used to express the correlation between quality of life scores, ABPI, type of intervention and age. The internal consistency based on correlations between items for each scale was assessed with Cronbach's alpha [36]. The recommended reliability standard for group-level comparisons is a reliability coefficient of 0.70, while comparisons between individuals demands a reliability coefficient of 0.90 [25]. The Wilcoxon Signed Ranks test was used to detect the responsiveness of within-subjects changes over time, before and one year after revascularization, in patients Forty-eight (53.3%) patients had IC of whom 26 (54%) were men. The remaining 42 (46.7%) suffered from CLI and 22 (52%) of them were men. There was a significant difference in age between the two groups with a mean age of 67 and 71 respectively (Table 1). One year postoperatively, sixty-six (73%) patients (38 with IC and 28 with CLI) remained in the study and secondary reconstructions were made on 7 (10%) patients during the follow-up. There were no significant differences at baseline in sex, age, ABPI and quality of life scores between the drop-out patients and the patients who completed the study. Further, there were no significant differences between the drop-outs and the remaining patients regarding the method of treatment or severity of ischaemia. Analyses between the comparable domains showed that the NHP scores were more skewed than the SF-36 scores, especially in emotional reactions, energy and social isolation (Figure 1). The "floor effect", the proportion of individuals having the lowest possible scores (SF-36 = 0, NHP = 100), was larger for the NHP scale in energy one year (19.7%...
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