Time to stop counting the tablets?

Abstract

We attempted to assess compliance using both a pharmacologic indicator (low-dose phenobarbital) and a return tablet count in 225 patients who were taking part in three separate studies. There were 216 patients (96%) who kept a follow-up appointment after 28 days; 161 patients appeared to have good compliance (90% to 109%) by return tablet count. Of these 161 patients, 51 (32%) had plasma phenobarbital concentrations (corrected for dose and weight) that were less than 90% of the lowest value previously found in normal volunteers, which suggested poorer compliance. When compared with the age-related volunteer values, 77 (48%) had values that were less than 90% of the lowest volunteer value. There were 6 of 10 patients with apparently excessive (greater than or equal to 110%) compliance by return tablet count and 4 of 12 who failed to return their container who also had phenobarbital concentrations that were less than 90% of the lowest volunteer value. We concluded that return tablet count grossly overestimates compliance.

Comparison of Morisky Medication Adherence Scale with therapeutic drug monitoring in apparent treatment–resistant hypertension

“…Pill count is also time-consuming and accurate in determining adherence only in 50%-70% of patients when compared with electronic pillbox 16,17 and 68% when compared with therapeutic drug monitoring. 18 More detailed self-reported questionnaires have been developed to detect medication non-adherence and avoid patients' tendency to report yes when they are simply asked if they have taken medications as prescribed. The four-item MMAS was shown to be correlated with level of BP control and found to be reliable when validated against prescription fill rate 7 and pill count.…”

Study on Adherence to Capecitabine Among Patients With Colorectal Cancer and Metastatic Breast Cancer

“…This method is an alternative or supplement to self-reporting. However, it does not supply information regarding the day and time at which the medication was taken, which may be a critical factor regarding the efficacy of treatment in some situations (24,26) . Metabolic levels in serum or urine are measurements of adherence presenting greater objectivity, but also do not describe the day and time at which the medication was taken and can also be manipulated by patients (an extra dose of a medication may be taken before a visit).…”

Assessment and Measurement of Adherence to Oral Antineoplastic Agents

“…14 Pill counts, requiring patients to return unused pills at each visit so that the number of missed doses can be calculated, have also been shown to overestimate the number of pills actually taken. 15,16 Patients may throw away missed doses to avoid being viewed as nonadherent. Nonetheless, pill counts are often used as an adjunct to self-report.…”