Drug-induced injury is common. Independent risk factors for adverse drug events in the ambulatory setting include advanced age, multiple comorbid conditions, and the use of high-risk medications requiring close monitoring. For example, failure to appropriately monitor older patients receiving drug therapy accounts for 36% of preventable adverse drug events in the ambulatory setting.¹

Efforts to improve monitoring within organizations are hampered by a lack of comprehensive and specific guidelines for the laboratory monitoring of high-risk medications.² Monitoring guidelines for selected drugs exist in recommendations of organizations such as the American Heart Association guidelines to manage heart failure,³ the American Geriatrics Society Assessing Care of Vulnerable Elders medication quality indicators,⁴ and the National Quality Forum–endorsed measures.⁵ A nationwide baseline monitoring assessment study⁶ developed more comprehensive guidelines for medications used through 2000, among which a subset of 14 were updated and adopted for an intervention trial between 2002 and 2003 within a single health maintenance organization.^7,8

We sought to develop an updated and comprehensive list of drugs requiring laboratory monitoring for an electronic medical record–embedded clinical decision support intervention at a multispecialty group practice for medications in clinical use during 2008. The intent of the updated guidelines was to include drugs introduced to the market since December 2000, the date of the literature review for the original drug and laboratory monitoring recommendations published by Raebel et al⁶ in 2005, as well as to update laboratory test and frequency recommendations based on 2007 changes in monitoring recommendations.⁹ Herein, we describe the development of guidelines to monitor high-risk medications in the ambulatory setting using a 2-step consensus-based approach, including a national expert advisory panel and local leaders to select candidate medications for monitoring and to determine the frequency of laboratory monitoring. To estimate the potential effect of our guidelines on actual practice, we determined the use frequency of the guideline drugs and the prevalence for each of the recommended laboratory tests. The specific objectives of this study were (1) to develop recommendations to guide the monitoring of high-risk medications in the ambulatory setting, (2) to assess the use prevalence of candidate medications for monitoring, and (3) to determine completion of recommended testing for medications dispensed among the patient population.

Study Setting and Population

This study was conducted in a large multispecialty group practice that provides most medical care to members of a closely associated health plan based in the New England area of the United States. The group practice employs 250 outpatient clinicians at 30 ambulatory clinic sites. The practice uses the EpicCare Ambulatory (Epic, Verona, WI) electronic medical record system and provides medical care to approximately 180,000 individuals. For this analysis, we included patients if they received care from the multispecialty group practice, were 18 years or older, and obtained insurance coverage from the health plan between January 1, 2007, and July 31, 2008. Patients had to be continuously enrolled during the observation period and not residing in a long-term care facility. Data about medication exposure were derived from the prescription drug claims of the health plan. Data about laboratory test completion were derived from the multispecialty group practice electronic medical record.

Determination of High-Risk Drugs and Laboratory Monitoring Guidelines

Laboratory monitoring guidelines for high-risk drugs were developed using a sequential process adapted from an approach created and tested for a study⁶ conducted within the Health Maintenance Organization Research Network Center for Education and Research on Therapeutics. This approach used an advisory committee of national experts and local health plan leaders, including practicing clinicians and pharmacists and experts in patient safety and geriatric pharmacotherapy. The charge for this group was as follows: (1) to review a comprehensive initial list of medications requiring monitoring; (2) to assess the importance of including monitoring recommendations to evaluate efficacy, safety, and clinically relevant drug–drug interactions; and (3) to determine the need to include infrequently prescribed medications in the guidelines. The initial list of high-risk drugs included those commonly implicated in adverse events among patients in the ambulatory setting¹ and those associated with adverse events leading to emergency department visits,¹⁰ as well as drugs with low monitoring rates,^6,11 drugs included in national quality guidelines,⁴ and drugs with black box warnings.¹²

We asked panel members to participate in an Internet-based questionnaire administered in a 2-round modified Delphi process¹³ between August and October 2008. Panelists were asked whether electronic monitoring alerts should be sent to primary care physicians, specialists, or both and whether monitoring alerts should be generated for infrequently dispensed or effectively obsolete medications. Panelists were also asked to rate the importance of monitoring each candidate medication for efficacy, toxic effects, and drug–drug interactions. Each question was answered based on a 5-point Likert-type scale to evaluate agreement or disagreement with statements concerning the importance of monitoring each medication or medication class for the domain assessed. The scale ranged from 1 (indicating “strongly agree”) to 5 (indicating “strongly disagree”).

After the first round of the survey, we eliminated questions for which there was agreement and readministered questions for which there was lack of consensus. Consistent with other modified Delphi methods, consensus for a question was defined by agreement on categorization by at least a majority (>50.0%) of respondents.¹³ We then administered a second questionnaire to participants. In this round, panelists were reminded of their original responses to individual questions and were given the group’s aggregated response to the questions in the first round. At this stage, each participant was given the opportunity to revise his or her response to increase consensus with the succeeding round. The results of the Delphi process informed the selection of the final high-risk drug list.