Measuring Adherence Jonathan Shuter, M.D. Treatment Adherence Network Meeting 2/27/01

Measuring Adherence--One Extreme “I firmly believe that if the whole materia medica as now used could be sunk to the bottom of the sea, it would be all the better for mankind--and all the worse for the fishes.” 1860: Oliver Wendell Holmes to the Massachusetts Medical Society

Measuring Adherence--The Other Extreme D.O.T.

Measuring Adherence--The Middle Ground Methods that quantify missed and taken doses Methods that measure physiologic effects Methods that assess systemic blood levels of drug

Self-Report Cheap Correlated with virologic outcomes (report of non- adherence is more reliable than report of adherence) Overestimates adherence Pro’s Con’s

Clinician-Estimated Adherence CheapMost poorly correlated of all measures with actual adherence Pro’s Con’s PROVIDERS ARE TERRIBLE JUDGES OF ACTUAL ADHERENCE AND OF THEIR PATIENTS’ ABILITY TO ADHERE!

Pill Counts Cheap Useful adjunct to self- report Overestimates adherence –“Pill dumping” Time consuming Casts provider in role of medication monitor, not ally/advocate Pro’s Con’s

Pharmacy Records Cheap Useful adjunct to self- report Cannot stand alone as adherence measurement method –One patient may use many pharmacies –Picking up prescriptions does not equate with taking medications –Patients may have other sources of medications Pro’s Con’s

Electronic Monitoring Best correlation with virologic outcomes Data is available in a computer accessible format Allows more detailed view of non-adherence patterns (weekends, nighttime, etc.) Expensive Poor patient acceptance Not infallible (patients can open bottle and not take pill) Not compatible with pillbox Usually only measures one medication Pro’s Con’s

Measuring Adherence--The Middle Ground Methods that quantify missed and taken doses Methods that measure physiologic effects Methods that assess systemic blood levels of drug

Indirect Laboratory Markers AZT=========> Increased MCV ddI==========> Increased uric acid Indinavir======> Increased bilirubin

Laboratory Markers Viral load CD4 Genotypic/phenotypic resistance

Measuring Adherence--The Middle Ground Methods that quantify missed and taken doses Methods that measure physiologic effects Methods that assess systemic blood levels of drug

Plasma Levels Correlates with virologic outcomes Only method that ensures that the patient actually ingested the drug May allow insight into absorption or drug interaction problems Very expensive Levels are extremely variable Only provides information about the last dose Pro’s Con’s

Montefiore Data

30/106 (28.3%) patients prescribed ART responded “Never” [miss medications], every time they were interviewed. These patients are not distinguished by any specific characteristic measured in the study. There are trends toward underrepresentation of females and IDUs in this group. Analyzed variables include age, gender, ethnicity, HIV risk behavior, AIDS, adverse effects, and depression score.

Conclusions There is no perfect method or combination of methods available to measure adherence Nevertheless, numerous methods of measurement correlate with virologic outcomes, and thus provide useful information Some method of adherence measurement should be used for all patients, but decisions regarding which method/s should be individualized

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