Validation of an instrument to assess patient attitudes towards prescribing of pharmaceuticals by doctors.

Objectives: To establish the reliability and validity of a questionnaire designed to assess Chinese patients' attitudes towards pharmaceuticals that may influence the prescribing behaviours of their doctors.

Study Design: A draft questionnaire of 48 items was designed in English, translated into Chinese, and then back-translated into English. After establishing for content and face validity, it was administered to a convenience sample of patients. Responses were factor analysed to establish construct validity and to reduce the questionnaire's length.

Population: Hong Kong Chinese patients (n = 387) who visited one of 24 primary care doctors.

Outcomes Measured: Derived factor score means were compared among various age, gender and education groupings.

Results: A final 21-item questionnaire was produced. Spearman's rank correlations indicated the instrument was relatively stable over repeated applications. Patients' attitudes were found to be multidimensional. The three-factor solution achieved a simple structure and accounted for 40% of the variance among the 21 items. Items loading heavily on each construct were internally consistent. Nine items measured patients' attitudes towards careful use of medications. Six questions measured a preference for information exchanges between patients and doctors. Six items measured patients' scepticism concerning the need for pharmaceuticals to hasten recovery from most illnesses. The three factors yielded factor score means that discriminated among the patients as expected.

Conclusions: The questionnaire met adequate standards for reliability and validity. It is suitable for further use in investigating Chinese patients' attitudes concerning pharmaceuticals and how these attitudes might influence their physicians' prescribing behaviours.