Patient questionnaires in primary health care. Validation of items used in asthma care.

OBJECTIVE: To evaluate each item in a patient questionnaire for the purpose of investigating whether the validity of each item is acceptable. DESIGN: The questionnaire was completed by the patients at an ordinary follow-up visit for their asthma, and within 1 week a nurse interviewed them by telephone with the aim of analysing the validity of each item through the use of predetermined criteria. SETTINGS: Patients with asthma in primary health care settings in Sweden. STUDY PARTICIPANTS: Fifty-one patients were consecutively included from three different primary health care units. RESULTS: Nine of 13 items had an acceptable validity. The four items that were not found to have acceptable validity were developed further. CONCLUSION: Evaluating each item in a questionnaire by means of interviews with the specific patient population is a useful method of assuring that the intention of the patient questionnaire has been met.