Development of a support skill scale in insulin therapy: a nationwide study in Japan.

Summary The aim of this cross-sectional, nationwide study in Japan was to develop a support skill scale for insulin therapy (IT-SSS) and to evaluate its validity and reliability. The sample consisted of 1604 nurses at 123 hospitals throughout the country. The factor validity, known-group validity, convergent validity, discriminant validity and internal consistency of IT-SSS were assessed. IT-SSS consisted of 26 minimum and 25 standard support skills. They included 4 subscales for minimum skills: management strategy for hypoglycemia, education about insulin injection technique, individual assessment and support about insulin rejection, and collaboration with medical professionals and patient/family. Three subscales for standard skills: apprehensions concerning the will and emotion of the patient, management for blood glucose control, and coordination in insulin management. Cronbach's alpha coefficient was between 0.75 and 0.90, suggesting strong internal consistency. Multitrait analysis showed that convergent validity was complete, and discriminant validity was found to be almost complete in both minimum and standard skill scales (scaling success rates of 97.6% and 98.7% across all subgroups, respectively). Known group analysis clearly showed that specialist nurses have significantly higher skills than general nurses. These findings indicate that IT-SSS has a reasonable factor validity, convergent validity, discriminant validity, known group validity, and internal consistency.