Utility of the Morisky Medication Adherence Scale in gout: a prospective study

Abstract

BackgroundThe outcomes of any chronic illness often depend on patients’ adherence with their treatment. A tool is lacking to assess adherence in gout that is standardized, allows real-time feedback, and is easy to understand.ObjectiveWe set out to evaluate the utility of the 8-item Morisky Medication Adherence Scale (MMAS-8) in monitoring medication adherence in a multiethnic Asian gout cohort on urate-lowering therapy (ULT).MethodsThis cohort study recruited patients with gout where baseline and 6-monthly clinical data, self-report of adherence, and health status by Gout Impact Scale (GIS) and EuroQoL-5 dimension 3 levels were collected. Those who received at least 9 months of ULT were analyzed. Convergent and construct validities of MMAS-8 were evaluated against medication possession ratio (MPR) and known groups, clinical outcomes, and patient-reported outcomes. Internal consistency and test–retest reliability were assessed using Cronbach’s alpha and intraclass correlation coefficient (ICC), respectively.ResultsOf 91 patients, 92.3% were male, 72.5% Chinese with mean age 53.5 years. MMAS-8 (mean 6.17) and MPR (mean 96.3%) were poorly correlated (r=0.069, P=0.521). MMAS-8 did not differ between those who did or did not achieve target serum urate (SU) <360 µmol/L (P=0.852); or among those whose SU improved, stagnated, or worsened during follow-up (P=0.777). Adherence was associated with age (β=0.256, P=0.015) and education level (P=0.011) but not comorbidities, polypharmacy, or flare frequency. Concerns for medication side effects and anxiety or depression were associated with lower MMAS-8 (P<0.005). Internal consistency was acceptable (α=0.725) and test–retest reliability was satisfactory (ICC =0.70, 95% confidence interval [CI] 0.36–0.88).ConclusionMMAS-8 had limited construct validity in assessing medication adherence to ULT in our gout patients. Nevertheless, it identified patients bothered or worried about ULT side effects, and those with underlying anxiety or depression, for whom targeted education and coping support may be useful.

Cost‐effectiveness of an adherence‐enhancing intervention for gout based on real‐world data

“…Other significant predictors of non‐adherence among Singaporeans with gout include presence of comorbidities, patient marital status, and education level . Consistent with the published literature on gout, local patients with comorbidities tend to be more adherent .…”

“…Only 24% of Singaporean patients on gout medication are highly adherent based on their Morisky Medication Adherence Scale‐8 (MMAS‐8) score, a validated patient self‐report scale that has been found to reliably assess and predict patient medication‐taking behavior . Another local study based on clinical outcome measures (whether patients achieve target SU levels) found that only 25% of patients had controlled SU levels during 1 year of regular care.…”

“…Many view gout as episodic and mistakenly discontinue ULT after symptomatic treatment . Perceived or experienced adverse effects also deter patients and prescribers, especially as ULT can trigger acute flares when first initiated . Additionally, poor self‐conviction in being able to successfully execute adherent behavior (ie low self‐efficacy) has been linked to non‐adherence …”

“…It has been suggested that patients who are more proficient in managing chronic conditions become better adherers . Comorbidities also signal more life‐threatening conditions that realign patient attitudes toward adherence . Married individuals are also more likely adherent because of practical support from spouses in taking medication .…”

“…Married individuals are also more likely adherent because of practical support from spouses in taking medication . Notably, gout patients with formal education in Singapore are found to be less adherent and possibly more critical of advice from their doctors …”