Drug therapy lab safety monitoring can be improved
Drug therapy lab safety monitoring can be improved
New research has shown that a computerized tool in the hands of health care professionals who work together can effectively increase the number of patients who receive laboratory safety monitoring of drug therapy. What isn't yet known, according to lead researcher Marsha Raebel, PharmD, investigator and pharmacotherapy research and clinical trials manager for Kaiser Permanente Colorado, is whether the additional safety monitoring translates into improved patient outcomes.
"We found that you can make a difference in how much safety monitoring is done and that pharmacists can have an impact," she tells Drug Formulary Review. "We still need to determine if it affects outcomes."
Raebel says while there have been many calls for increased safety monitoring, there has been relatively little in scientific literature documenting that interventions improve the rate of monitoring.
The research report, published in the May issue of Pharmacotherapy, says suboptimal laboratory monitoring of drugs that pose a risk of organ system toxicity or electrolyte imbalance or of drugs that require dosage adjustment in patients with organ dysfunction is considered a medication error. Laboratory monitoring medication errors occur when indicated tests are not conducted, when an avoidable delay in responding to abnormal test results occurs, or when follow-up of laboratory results is inadequate.
The randomized trial examined whether a computerized model that alerts pharmacists to missing laboratory results increases the percentage of patients who receive guideline-recommended safety monitoring during ongoing drug therapy. The trial was conducted at Kaiser Permanente Colorado's outpatient medical offices with some 340,000 individuals randomly assigned to either the intervention group or control group (usual care) at the beginning of the study. Each month, new members were randomly assigned; by the end of the study, more than 400,000 individuals had been included.
To create the intervention tool, staff from the departments of pharmacy, research, primary care, laboratory, and clinical technology collaborated to develop and implement computer programming to link drug and laboratory data. From the linked data, the researchers provided reports of drug dispensing coupled with drug-specific laboratory parameters that were missing (either a lab test had not been ordered or a patient did not comply with undergoing a test). Daily reports were electronically sent to the clinical pharmacy call center, where a centralized team of clinical pharmacists telephoned patients to address drug-related issues.
Two drugs dropped
Although 14 drugs were initially selected for the study, two (ticlopidine and felbamate) subsequently were dropped due to a low number of prescriptions. Raebel tells DFR the researchers looked at many sources for published monitoring guidelines and compiled from them a list of drugs for which monitoring was recommended. They cut that list to those they had the capability to monitor and then asked clinicians to determine which of those drugs would be most important to monitor. "It was important that the final list was agreed to by everyone," she said, "specifically relating to safety monitoring and not to efficacy."
Selection criteria applied in the process included FDA black box warnings, published clinical guidelines, perceived potential for adverse consequences related to a lack of monitoring, and current intervention services for the drugs (such as warfarin already being monitored by the clinical pharmacy anticoagulation services).
The final list of study drugs included amiodarone, atorvastatin, carbamazepine, divalproex, gemfibrozil, lithium, lovastatin, metformin, phenytoin, pioglitazone, simvastatin, and theophylline.
A guideline was developed to help call center pharmacists manage abnormal lab results. Primary care administrators, key physician clinicians, pharmacists and pharmacy administrators, and health plan researchers reviewed and approved the guideline. When lab results were abnormal, the call center pharmacists used standardized scripts and wrote notes in the electronic medical record that were forwarded to the patients' providers. If urgent actions were needed, the pharmacists telephoned the providers directly.
During the study, some 9,139 patients received ongoing therapy with at least one of the study drugs. Of this group, 470 patients were prescribed two study drugs and 21 were prescribed three, resulting in 9,651 individual patient-drug combinations. The researchers said they found no significant difference between the 4,515 patients in the intervention group and the 4,624 patients in the control group.
Significantly improved monitoring
Drug therapies were monitored in the recommended time frame in 64% of patient-drug combinations in the intervention group, compared with 58% in the control group. Improvements in intervention group monitoring were statistically significant for amiodarone, theophylline, carbamazepine, lithium, phenytoin, and metformin.
Call center pharmacists ordered 1,981 lab tests for study drugs and patients completed 1,472 of the tests, although not all were completed in the recommended time frame. The most common pharmacist intervention was ordering a serum creatinine level for 558 patients taking metformin. Other interventions included ordering liver enzyme tests, complete blood counts, or serum drug concentrations in 364 patients taking carbamazepine; liver enzyme tests or serum drug concentrations in 326 patients taking phenytoin; serum creatinine concentrations, complete blood counts, and/or serum drug concentrations in 267 patients taking lithium; and serum drug concentrations in 250 patients taking theophylline.
Of the 1,472 tests the pharmacists tracked that were eventually completed, 307 (21%) yielded abnormal results, including 181 serum drug concentrations outside the therapeutic range and 126 instances of abnormal serum creatinine, alanine aminotransferase, aspartate aminotransferase, thyroid-stimulating hormone levels, and complete blood counts.
Raebel says the computerized alert system used by clinical pharmacists collaborating with physicians effectively increased the percentage of patients who received recommended laboratory monitoring during long-term therapy with drugs that can cause organ system toxicity or electrolyte imbalances or with drugs that require dosage adjustment when patients have organ dysfunction.
According to the study, among the drugs associated with the greatest differences in monitoring between the intervention and control groups were lithium and carbamazepine. "These were the only study drugs for which three laboratory monitoring tests were recommended," the report said. "Increasing numbers of recommended tests may increase the opportunities for monitoring errors. Even with knowledge of drug toxicity, busy prescribers can easily forget to order all of the recommended laboratory tests when prescribing drugs with several toxicity risks and many recommended monitoring tests. Monitoring may have improved in the intervention group at least partly because the computerized alert served as a reminder by highlighting missing test results for the call center pharmacists."
No difference for some drugs
In contrast, Raebel said, monitoring did not differ between intervention and usual-care patients receiving pioglitazone and those receiving the combination of a statin plus gemfibrozil, drugs for which only one lab test is recommended. Monitor-ing rates in both groups were relatively high and Raebel speculated the reasons for the lack of difference may differ from the reasons for the drugs with three recommended laboratory monitoring tests. "Physicians might be more knowledgeable about recommended monitoring for these two drugs than for others, or the finding could have been a ceiling effect given that the monitoring rates were relatively high in each group," she said.
For patients prescribed divalproex, monitoring did not differ between intervention and usual care. Raebel said that although the study design did not enable the researchers to evaluate reasons for the intervention's ineffectiveness in these patients, possible reasons include differences in patient characteristics between groups, such as seizure vs. mental health diagnosis or high vs. low drug doses, and differences in provider characteristics, such as their clinical judgment about importance of lab monitoring for divalproex.
"Our findings exemplify the utility of merging pharmacy and laboratory data and of providing that information to clinical pharmacists who focus on improving the quality and safety of care for ambulatory patients," Raebel wrote. "A barrier to the involvement of pharmacists in this type of initiative is that they cannot easily access patients' clinical data in many ambulatory settings. Our system overcomes this barrier because it can be implemented in essentially any health care setting where pharmacy dispensing information and laboratory claims data are available and can be linked."
Raebel points out that published recommendations often don't give specific monitoring frequencies, only saying monitoring tests should be performed "periodically" or "as appropriate." The researchers asked clinicians for guidance on intervals a prudent physician would follow. She said they were looking for the lowest test frequency a wise clinician would follow. The resulting study guidelines call for testing every six months or one year, depending on the drug.
She tells us there are two main messages people should take from the research: 1) many facilities have the ability to link laboratory and pharmacy data and doing so can help identify gaps in laboratory monitoring; and 2) by encouraging collaboration, it is possible to increase what experts have said is appropriate safety monitoring.
[Contact Dr. Raebel at (303) 614-1260 or e-mail [email protected].]
New research has shown that a computerized tool in the hands of health care professionals who work together can effectively increase the number of patients who receive laboratory safety monitoring of drug therapy.Subscribe Now for Access
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