Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Measuring Therapeutic Adherence in Systemic Lupus Erythematosus (SLE) Using the Medication Event Monitoring System (MEMS).

Marengo,  Maria F., Waimann,  Christian A., de Achaval,  Sofia, Cox,  Vanessa L., Garcia Gonzalez,  Araceli, Richardson,  Marsha N., Suarez-Almazor,  Maria E.

Background:

Treatment adherence is crucial in chronic diseases such as SLE. Multiple methods for measuring adherence have been proposed. Electronic monitoring is considered one of the most accurate measures of adherence. The objective of our study was to quantify adherence to medical therapy in patients with SLE with electronic monitoring.

Methods:

This study was part of a 2– year prospective cohort of 110 patients with SLE from 2 publicly-funded county hospitals, in which 74 patients agreed to have their SLE drug therapy electronically monitored, with MEMS® caps (AARDEX). These are medication bottle caps with a microchip which records the time and date of bottle openings. Adherence to daily medications was determined as the percentage of days with correct number of doses taken. Adherence to weekly methotrexate (MTX) was determined as the percentage of doses taken within intervals of 7 ± 1.75 days. We also estimated percentage of prescribed doses taken (not considering dosing interval). MEMS® data was downloaded with each refill. Patient outcomes were assessed at baseline, 3, 6, 12, 18 and 24 months including Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), Systemic Lupus International Collaborating Clinics Damage Index (SLICC), SF-12 and flares. We also collected baseline Medical Outcome Study social support (MOS), Center for Epidemiologic Studies Depression Scale 10 items (CDES-10) and sociodemographic variables. 85% of the patients completed 2 years follow-up; for the remainder we used the last observation for analysis. Statistical analysis was performed with SAS

Summary of Results:

89% were female, 49% African-American, and 46% Hispanic; mean age was 36y (±11), disease duration 6y (±5), SLEDAI 3.2 (±3.2) and SLICC 0.8 (±1.2); 97% received prednisone, 92% hydroxychloroquine, 30% mycophenolate mofetil, 13% MTX, 8% azathioprine (not all medications were monitored with MEMS) (table). Adherence for doses taken on schedule (day/wk) was 64% for prednisone and 46% to 62% for the other drugs. Only 15 (20%) of the patients had an average adherence >= 80%. Depression was associated with worse adherence (r=-0.24, p<0.04), and increasing SF-12 mental scores (MCS) with better adherence (r=0.31, p=0.02). Mean SLEDAI decreased significantly overtime (p<0.002); % doses taken had a small but significant correlation with decrease in SLEDAI for all drugs (r=-0.25, p<0.04) and for prednisone alone (r=-0.31, p<0.02); % doses on schedule showed similar trends but did not reach statistical significance. No differences were observed for SLICC.

DrugsNTotal days monitoredMean dose% prescribed doses taken on schedule% prescribed doses taken
Prednisone65511 (±260)12 mg/day64.3 (±24)75.9 (±24.6)
Hydroxychloroquine51556 (230)248 mg/day56.2 (±26.2)72.0 (±26.1)
Methotrexate7350 (267)134 mg/week62.0 (±28.7)94.6 (±30.9)
Micophenolate Mofetil3459 (178)1087 mg/day46.3 (±20)67.1 (±22.6)
Average all drugs7458.6 (±24.9)73.3 (±25.2)

Conclusion:

Adherence to drug therapy measured by electronic monitoring appears to be low in patients with SLE, and related to depression and overall mental health. Only 1 out of 5 patients was at least 80% adherent. Low adherence appeared to have a detrimental effect on health outcomes.

To cite this abstract, please use the following information:
Marengo, Maria F., Waimann, Christian A., de Achaval, Sofia, Cox, Vanessa L., Garcia Gonzalez, Araceli, Richardson, Marsha N., et al; Measuring Therapeutic Adherence in Systemic Lupus Erythematosus (SLE) Using the Medication Event Monitoring System (MEMS). [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1865
DOI: 10.1002/art.29630

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