Background:
Evidence suggest that individuals with diabetes do not easily adopt smoking cessation interventions. Assessing the acceptability of such interventions is crucial before implementation, yet there are no quantitative measures which evaluate satisfaction and perceived usefulness of smoking cessation interventions among individuals with diabetes.

Objectives:
Validate and assess the internal consistency of two self-developed instruments measuring satisfaction and perceived usefulness of a smoking cessation intervention among individuals with diabetes.

Methods:
The instruments were developed and validated in English, then translated into Maltese. The satisfaction questionnaire contained eight statements while the perceived usefulness questionnaire had fourteen; both rated on a 5-point Likert scale. Content validation involved five tobacco cessation facilitators rating item relevance using a 4-point ordinal rating scale, suggesting improvements, and later assessing the conceptual equivalence of the translated questionnaires using a similar scale. Unanimous agreement among experts was required for item relevance and equivalence. Thirty-four individuals with type 1 or type 2 diabetes, attending a diabetes-specific smoking cessation intervention, received either the Maltese or English versions of the questionnaires. Internal consistency was measured using Cronbach's alpha scores.

Results:
Two rounds of content validation resulted in minor changes to the questionnaires, including removing one item and adding another to the perceived usefulness questionnaire. Experts unanimously agreed on item relevance and conceptual equivalence. Fifteen participants completed the Maltese versions of the questionnaires, while sixteen completed the English versions. Cronbach's alpha scores were 0.87 and 0.91 for the Maltese and English versions of the satisfaction questionnaire, and 0.94 and 0.96 for the Maltese and English versions of the perceived usefulness questionnaire. All item-scale correlations were >0.4.

Conclusions:
These findings provide initial validation for utilizing the developed instruments to assess satisfaction and perceived usefulness of smoking cessation interventions among individuals with diabetes. Further validation with a larger sample and factor analyses is recommended.