Liver and Thyroid Monitoring in Ambulatory Patients Prescribed Amiodarone in 10 HMOs

Abstract

he association between amiodarone and liver, thyroid, ocular, cardiac, skin, and pulmonary adverse events has been recognized for more than 20 years. [1][2][3][4][5][6][7][8] Asymptomatic elevation of liver enzymes occurs in 5%-24% of patients prescribed amiodarone, symptomatic liver injury occurs in up to 3%, 4,9 and thyroid dysfunction (including both hyper-and hypothyroidism) occurs in 2% to 24%. [10][11][12] Nearly all cases of liver and thyroid function abnormalities associated with amiodarone therapy are reversible with prompt recognition and management. If thyroid dysfunction occurs or if liver enzyme elevations exceed 3 times the upper limit of normal, the amiodarone dosage should be reduced or the drug discon-ABSTRACT BACKGROUND: Amiodarone can cause liver and thyroid toxicity, but little is known about compliance with laboratory tests to evaluate liver and thyroid function among ambulatory patients who are dispensed amiodarone.OBJECTIVES: The primary objective of this study was to identify the proportion of ambulatory patients who had liver aminotransferase and thyroid function tests during amiodarone therapy. Secondary objectives were to (1) describe factors associated with receipt of laboratory tests and (2) determine the accuracy of administrative data for assessing aminotransferase and thyroid function monitoring.METHODS: This retrospective cohort study was conducted at 10 health maintenance organizations (HMOs) for the dates of service from January 1, 1999, through June 30, 2001. Participants included 1,055 patients dispensed amiodarone for at least 180 days within this date range; these patients were not necessarily new starts on amiodarone. Administrative claims data were analyzed to assess the percentage of patients with completed alanine/aspartate aminotransferase and thyroid function tests. Depending on the HMO site, electronic or paper medical records were reviewed to evaluate the validity of administrative claims data. Logistic regression models were used to explore factors associated with receipt of laboratory tests.RESULTS: Both aminotransferase and thyroid function tests were completed in 53.3% of patients within a 210-day follow-up period that included the 180-day period of amiodarone dispensings plus 30 days. Thyroid function, with or without liver function (aminotransferase tests), was assessed in 61.9% of patients, and aminotransferase tests, with or without thyroid function, were assessed in 68.2% of patients. After adjusting for patient characteristics and site, the factor most strongly associated with having both types of laboratory tests evaluated was concomitant therapy with a statin (adjusted odds ratio (OR) 1.55; 95% confidence interval (CI), 1.05-2.29). Other factors associated with having both types of laboratory tests evaluated included the number of outpatient visits in the 6 months before the period of amiodarone dispensings (adjusted OR 1.06; 95% CI, 1.00-1.13 for each additional 5 visits) and living in a neighborhood where a higher median percentage of people had a hig...

Evaluation of a Pharmacist-Managed Amiodarone Monitoring Program

“…A study of 10 managed care organizations in [2003][2004] found that only about one-half of all ambulatory patients on amiodarone received both recommended tests for liver and thyroid function. 10 Bickford and Spencer (2006) measured adherence to the NASPE guideline for baseline monitoring among 45 patients initiated on amiodarone therapy during a hospital admission at a medical university. The authors found that 82% received baseline thyroid function tests, and 87% received baseline liver function tests.…”

“…Laboratory test monitoring was recorded at baseline (up to 6 months before the index date), from 1-6 months after the index date, 7-12 months after the index date, and at any time during the year (months [1][2][3][4][5][6][7][8][9][10][11][12]. Alanine aminotransferase (ALT) was evaluated for liver function.…”

The onset time of amiodarone-induced thyrotoxicosis (AIT) depends on AIT type

“…In patients under amiodarone therapy, evaluation of thyroid function is usually recommended at 6-month intervals (1,2,3,24). Based on the present data, we suggest a closer follow-up (i.e.…”

Patient Completion of Laboratory Tests to Monitor Medication Therapy: A Mixed-Methods Study

“…We may have missed monitoring that was done outside of our system, but prior research suggests that this is unlikely. 47 Third, the interviewed patients may not be representative of the whole population (all white and educated); the same barriers that prevent completing testing may also impede appearing for an interview. We attempted to overcome that issue with telephone interviews to reach more patients, but we cannot rule out that we missed patients who had other major barriers to both testing and interviewing.…”