S118. THE ASSESSMENT OF ADHERENCE TO ORAL ANTIPSYCHOTIC MEDICATIONS: WHAT HAS CHANGED IN THE PAST DECADE? (2019)

Poor adherence to oral antipsychotic medications is arguably one of the most important modifiable risk factors contributing to relapse of psychotic symptoms and rehospitalization. Adherence to oral medications has been assessed using multiple approaches. In a previous review of 161 studies, spanning 3 decades, we found that self-report and other non-objective measures were the primary means of assessing adherence to oral medications, and that consensus regarding the definitions of adherence was completely lacking. That article as well as expert consensus guidelines published later presented recommendations for improving the assessment of adherence going forward. Here, we examined the next decade of studies measuring adherence to antipsychotic medications in schizophrenia to determine what may have changed. We searched the peer reviewed literature published between January 1, 2007 and December 31, 2017 using Google scholar, Science Direct, CINAHL, PsychINFO, PsychARTICLES and Medline search engines to find articles specifically measuring adherence behavior to oral antipsychotic medications. Search terms were medication adherence or medication compliance or medication acceptance or medication follow-through or medication concordance or medication persistence AND schizophrenia. The search yielded 666 articles, 303 of these were included, and represented over 500,000 individuals with schizophrenia. The number of studies in which adherence behavior has been measured has increased by nearly 6 times in the past decade. Indirect methods including the report of the person, the report of the treatment team and the report of a significant other remain the most commonly used. Several novel approaches including tracers embedded in pills, electronic immediate self-report, and unannounced in-home pill counts were used. In the past decade, compared to the 3 previous decades, there has been a decrease in the use of measures based upon input from the treatment team X2(1)=3.96 p=.0457) and significant others (X2(1)=4.87 p=.0273) and a substantial increase in the use of electronic claims data (X2(1)=18.24 p=.0001). While the use of objective measures remains relatively infrequent, their use has increased significantly (X2 (2)=12.56 p<.002). The percentage of studies using multiple methods to assess adherence actually decreased in the past decade (X2 (1)=7.00 p=.008). Definitions of adherence remain extremely variable with cutoffs from 67% to 95%. Different categorizations including 3, 4, 5, 6, and 7-point scales were utilized. Only limited literature exists on the use of novel technologies such as cameras that verify ingestion and microchips in the tablets themselves. Self-report continues to be the most commonly used measure of adherence, possibly because it is the easiest to obtain. The decreased reliance on provider report is supported by research demonstrating that providers are poor judges of level of medication adherence. Claims data is increasingly providing valuable data on large numbers of individuals to impact practice. As recommended in the previous review and the expert consensus guidelines, the use of objective measures of adherence has substantially increased; but overall these measures continue to be used infrequently. The consensus guidelines also recommended the use of multiple measures of adherence because no measure identifies exactly how much medication has been taken. This recommendation appears not to be being followed. The definitions of adherence remain widely variable despite consensus guidelines suggesting 80% as a cutoff that identifies adequately adherent individuals.