Measuring improvements in adherence Jennie Connor University of Auckland, New Zealand

2. Measuring improvements in adherence Jennie Connor University of Auckland, New Zealand

3. Do fixed dose combination pills or unit-of-use packaging improve adherence? • Systematic review of randomised trials • Effect on adherence and clinical outcomes • Only a small number of trials found, most poor quality • Some benefit but evidence is weak • What is a significant improvement? • Heterogenous adherence measures • How valid? • How reliable? • How useful in usual practice?

4. Direct methods (look for evidence of the drug in the body) Test for drug, metabolite or tracer in: urine blood saliva Indirect methods Pill counting Medication event monitoring (MEMS) Prescribing/dispensing records Self-report Diary Adherence questionnaire Appointment keeping Therapeutic response Methods for measuring adherence

5. How valid? = is it measuring what you intend it to? • What are you trying to measure? • Are they getting effective treatment? or • Are they following the regimen (dose and timing)? • No ‘gold standard’ with which to compare • Direct methods • only measure recent ingestion of drug • Pill counts and MEMS • Show medications/caps have been removed from the container • Pill counts over-estimate adherence • MEMS provides timing information, no doses

6. Prescriptions/dispensing • Little validity except discontinuation • Greatly over-estimate adherence • Self-report • Response varies greatly with context, relationship, and nature of questioning • Social desirability and recency effects • Generally over-estimates adherence. Good specificity for nonadherence • Formalised in questionnaires – can include adherence-related behaviours, barriers….e.g.PMAQ. Not for repeated use. • Medication diaries – more reliable information than recall. Details of timing. • Appointment keeping: raises index of suspicion • Therapeutic response: weak indicator

7. How reliable? Hard to know without a good reference standard • Accuracy of self report varies between settings • PMAQ and other formal instruments are designed and tested for reliability, informal interview is not. • Drug testing may vary between individuals, or over time

8. How useful in practice? • All methods have limitations: may need to use more than one • Consider the patient and clinician burden and cost • Self-report compares well with other measures in many studies and is most readily available • Need to think about a definition of clinically significant non-adherence • To distinguish those at high risk of treatment failure, rather than e.g. “80% rule”

9. Improving adherence measurement • In research • Defining acceptable adherence: is there a known threshold for effective treatment that needs to be reached? • Validation studies of measures – for this condition, this population • Multiple complementary measures and composite measures - standardisation • Distinguishing patterns of non-adherence – erratic, unwitting, intelligent. • What is a significant improvement in adherence for this drug or condition?

10. Improving adherence measurement • In practice • Will usually need to use simple and cheap methods • Partnership with patient to improve adherence and its measurement by self-report • Assessment of adherence as part of routine of care – a continuous process • Context-specific combination of measures : little place for routine pill counting: identifying patterns of non-adherence as well as extent • Consider poor attenders and poor responders as higher risk