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Table 2 Scale Statistics

From: Psychometric properties of an instrument for assessing the experience of patients treated with inhaled insulin: the Inhaled Insulin Treatment Questionnaire (IITQ)

  T1 T1 T1 T2 T2 T2
Measure (# of items) Test Retest Test-Retest Test Retest Test-Retest
Diabetes Worries (5)       
   Meana 74.0 74.5 p = .348 75.2 76.8 p = .009
   SD 16.7 16.9   17.4 16.2  
   % max, % min 0.2,7.7 0.6,8.1   0.4,9.0 0.4,9.3  
   Reliabilityb .71 .75 .81 .68 .70 .77
Perceptions of Insulin Therapy (16)       
   Meana 58.2 56.9 p = .001 57.0 56.4 p = .191
   SD 14.9 15.0   15.9 15.9  
   % max, % min 0.2,0.0 0.2,0.0   0.2,0.0 0.2,0.7  
   Reliabilityb .85 .87 .90 .84 .86 .85
Treatment Satisfaction (3)       
   Meana 53.3 54.1 p = .285 52.5 53.6 p = .248
   SD 21.4 21.2   23.9 24.6  
   % max, % min 2.2,1.6 1.8,1.8   2.8,2.8 2.3,4.6  
   Reliabilityb .83 .85 .83 .81 .85 .74
Treatment Preference (1)       
   Meana 69.2 66.8 p = .020 58.1 58.3 p = .887
   SD 26.0 25.3   30.3 29.0  
   % max, % min 3.7,21.0 3.5,16.9   7.4,13.8 6.9,11.6  
   Reliabilityb na na .73 na na .67
  1. a Test-Retest is the p-value for paired t-test of difference in means across administrations.
  2. b Reliability for each administration is Cronbach's alpha (na = not applicable); Test-Retest reliability is the intraclass correlation coefficient.