Studying the Hurdles of Insulin Prescription (SHIP(C)):: development, scoring and initial validation of a new self-administered questionnaire

Background: Although insulin therapy is well-accepted by symptomatic diabetic patients, it is still often delayed in less severe patients, in whom injectable insulin remains under-used. A better understanding of patients' perception of insulin would eventually help physicians to adopt the most appropriate dialogue when having to motivate patients to initiate or to intensify insulin injection. Methods: The ' Studying the Hurdles of Insulin Prescription' ( SHIP) questionnaire was developed based on a list of concepts derived from three diabetic patients' focus groups, and was included into two cross-sectional studies with similar design: SHIP Oral study and SHIP Premix study. Diabetic patients treated with oral hypoglycaemic agents ( OHA; n = 1,494) and patients already treated with insulin ( n = 1,150) completed the questionnaire at baseline, 6- and 12 months. Psychometric properties were assessed: 1) structure analysis by Principal Component Analysis (PCA) with Varimax rotation, 2) internal consistency reliability ( Cronbach's alpha), and 3) concurrent validity ( Spearman correlation coefficients with the Fear of Self-Injecting ( FSI) score of the Diabetes Fear of Injecting and Self-testing Questionnaire. Reluctance/motivation towards insulin was assessed. Scores' ability to predict patients' insulin injection reluctance/motivation and initiation/intensification was evaluated with the Area Under the Receiver Operating Characteristic (ROC) Curve (AUC). Results: PCA analysis confirmed the structure of the 14 items grouped into 3 dimensions: ' acceptance and motivation', ' fear and constraints', and ' restraints and barriers' towards insulin injection. Internal consistency reliability was excellent ( Cronbach's alpha > 0.70); concurrent validity was good. The three scores were significantly predictive of patients' reluctance/motivation towards insulin injection initiation, as they were of patients' actual switch, except for the ' restraints and barriers' dimension. 'Acceptance and motivation' and 'fears and constraints' dimensions were also significantly predictive of patients' reluctance/motivation towards insulin intensification. By the end of the 12-month study, 179 of the initially OHA- treated patients had started insulin injections; 186 of the patients already treated with insulin had increased their injections. Conclusion: The SHIP questionnaire provides reliable and valid assessment of diabetic patients' attitude towards insulin and injections. The predictive power of scores for patients 'reluctance/motivation and actual treatment decisions demonstrates encouraging potential for further application in clinical practice.