Medication Errors Common Among Transplant Patients

NEW HAVEN, Conn. March 21 -- Transplant recipients typically require a complicated schedule of drugs that may be too convoluted for patients to keep straight, found researchers here.

During a 12-month period there were 149 medication errors identified during outpatient follow-up of 93 liver, kidney, and/or pancreas transplant patients, Amy L. Friedman, M.D., of Yale, and colleagues, reported in the March issue of Archives of Surgery.

More than half the mistakes were by patients, the investigators found.

Almost a third of the errors resulted in adverse events which affected the survival of the grafts, including nine episodes of graft rejection and six outright failed transplants, said the Yale group.

Overall, 17 patients were hospitalized and three required outpatient invasive procedures as the result of medication errors, she said.

The patients were prescribed a mean of 10.9 drugs each, which may have been too many drugs for the patients to safely track because 56% of the errors were classified as patient error, defined as "a failure to accurately use an available prescribed medication."

In addition to identifying the type of error, Dr. Friedman also sought to identify the root cause of the error-whether the error was made by a confused patient or by a doctor, nurse, or hospital.

Here, again, it was the patient at the root of most errors-101 of 149 occurrences.

By contrast, health care providers were identified as the root cause of 27% of the errors, which included 10% of errors that were linked to the transplant team itself.

Dr. Friedman and colleagues studied medication errors in all recipients of liver, kidney, and/or pancreas allografts at the Yale New Haven Organ Transplant Center from April 1, 2004 through March 31, 2005.

They sorted the errors into five categories: prescription error, delivery error, availability error (inadequate medication for a 24-hour period), patient error, and reporting error (failure to provide adequate information to identify the type, dose, or frequency of a medication).

The medication regimen was reviewed at every patient encounter and was also compared with the regimen prescribed by the transplant team.

Each difference between the medication review and the prescribed regimen prompted an inquiry to determine the cause of the discrepancy, she said.

But about a third of the errors were system errors, including 26% that occurred "prior to patient involvement in the process." The errors that pre-dated patient involvement were evenly divided between prescription errors-wrong drug or wrong dose- and delivery errors, meaning that the correct drugs were prescribed but pharmacists failed to the fill the prescriptions quickly enough.

Focusing on the root cause of the errors, Dr. Friedman said that financial issues were the root causes of 5% of the errors and pharmacists were identified as the root causes of another 10% of the errors.

The authors also pointed out that although many errors were listed as patient errors, the healthcare system also bears some responsibility for these. They wrote that "many of those errors ascribed to the patient seem to be unintentionally caused by a failure to understand the proper method of administration, which must be viewed as a communication error. This breakdown cannot be solely considered the patient's responsibility."

"Moving forward" they continued," the challenge will be to recognize and address communication gaps between providers and other providers and between providers and patients."

Dr. Friedman said the study was limited by its open-ended, observational design, which made it impossible to determine the frequency of events. Moreover, it is possible that the mechanistic definitions used to classify errors may not reflect the true error rate in other outpatient populations.

Moreover, this population might not even be typical of transplant populations, said Martin A. Makary, M.D., M.P.H. of Johns Hopkins in an invited critique.

Dr. Makary noted that the population in this study "had a high proportion of patients missing outpatient appointments, evidenced by a reported 45 'no shows' out of 264 scheduled appointments." That indicated, he said, "a low baseline level of general patient compliance compared with most outpatient clinics."

Finally the authors concluded that the study suggests that "targeted educational programs to help patients better understand their medications and to better participate in the monitoring of proper drug usage may lead to a significant reduction in errors at little cost and major benefit."