We chose not to use this variable as our primary dependent variable due to several limitations with the medication use question and its discrepancy in sample size with the ADHD question (elaborated later in the Discussion section).
Secondly, the unweighted sample sizes for ADHD-NCM (1,690) and ADHD-CM (3,735) groups do not add up to the total number of ADHD-diagnosed children (7,137 from Table 1) due to missing values for the medication use question.
It was optional to report timing of exposure for each of the medication use questions (the alternatives were gestational weeks 0 12 (1st trimester), 13 24 (2nd trimester) and 25 to delivery (3rd trimester)).
Pharmacists also ask patients about the indications for the medication, using questions like "what is this drug for?" or "how does this drug help?" To measure patients' knowledge of medication we shall calculate the proportion of drugs for which they give a correct response, based upon their medical problems and accepted indications for prescribing each drug [ 15].
We changed the medication-use question from "When you have a headache, do you take medicine or pills for it?" (response options: Every day; Most days; Every week; Every month; Less than once a month) to "On how many days in the last four weeks did you take medicine or pills because of headache?
Consistent with this, we observed no association between time period and reporting of medication use; these questions related to current medication use rather than medication use over a specified time period.
Eligible patients were then contacted by phone by the principal investigator and asked about symptom location, mode of onset, duration, pain severity, improving and worsening factors, medication use and questions related to the exclusion criteria.
These instructions are in short: Give all information to the care providers about your state of health; Ask the care provider when something is not clear to you; Discuss the surgical procedure with the care provider; Write down an overview of your medication use; Ask questions when your medication looks different from expected; Follow the instructions given by your care provider.
The health questionnaire included questions assessing demographics, comorbidities, and medication use and modified questions from the International Study of Asthma and Allergies in Childhood (Asher et al. 1995) and the Children's Health Survey for Asthma (Asmussen et al. 1999) to evaluate indicators of poor asthma control.
These questions included: demographic information (age, sex, education, etc)., oral health questions (personal oral care habits and oral health care services utilization), general health questions, medication use, labour force activity (income and employment status) and questions regarding smoking and alcohol exposure.
Our ability to capture cardiac events, comorbidities and mortality within the WA population in addition to their medication use will allow us to address questions around the effectiveness of these drugs in the broader population, taking into account a measure of adherence.
