Electronic monitoring gains more acceptance
Electronic monitoring gains more acceptance
Formerly clunky devices now cheap, user-friendly
Measuring adherence levels associated with any chronic illness is a headache, experts agree. When it comes to AIDS patients taking the new combination therapies, it can be a full-blown migraine.
Most of the time-honored ways of gauging compliance are not especially reliable, says Terry Blaschke, MD, chief of the division of clinical pharmacology and a professor of medicine at Stanford University in Palo Alto, CA.
Methods that rely on subjective reporting are prone to error and bias, he says. For one thing, "patients tend to remember what they did yesterday better than what they did a month ago," he says. Also, most patients want to please their providers, and tend to overestimate adherence, Blaschke says.
As for diaries and daily records, people forget to fill them out. Or, if they remember, they are less than truthful, studies have found.
Pill counts aren’t much better. Patients whose behavior was monitored by electronic devices have been caught in the act of emptying their nebulizers, or dumping their leftover pills the day of a scheduled clinic visit to avoid a scolding from their providers.
AIDS compliance more complicated
Figuring out whether people are taking all their pills is just part of the battle, adds Janice Wohltmann, vice president and general manager of APREX, a division of Apria Healthcare, a Menlo Park, CA, firm that makes electronic monitoring devices.
"With AIDS patients, there’s much more to it," she says. "In this case, you also need to know if the patients are taking the pills on time, and if they’re taking them the right way."
In one instance, Wohltmann says, an AIDS patient had been instructed to take his protease inhibitor either an hour before a meal or two hours afterward. Electronic monitoring found that technically, the patient was following directions very well.
"He was taking his Crixivan two hours after breakfast, and an hour before lunch," says Wohltmann. "That left him with a one-hour window in between the first two doses" not exactly what his physician had in mind.
Checking drug serum concentrations doesn’t work well with AIDS patients, either, says Blaschke, since many of the medications taken by AIDS are so quickly eliminated from the body. That doesn’t mean assaying for plasma levels isn’t useful, he adds; it’s just not useful for measuring compliance.
Electronic monitoring systems, once widely considered too clunky or too expensive to be feasible, are now thought by some experts on adherence to be a good solution for patients who have trouble with compliance. Blaschke says such systems are the best way to go, not only for getting reliable information on adherence, but also because the systems provide an effective way to intervene, as well.
"It’s possible to cheat with these devices," adds Wohltmann. "But to do so, you’ve got to be very consistent, day in and day out." At a cost ranging from 50 cents to $2 per day, the systems aren’t that expensive, either, especially when compared to an annual course of protease inhibitors.
Even in the field of TB, where experts extol the virtues of directly observed therapy (DOT), electronic monitoring is beginning to make inroads. New York City TB controllers, for example, have been using electronic monitoring for TB patients on a limited basis since 1994, and are about to expand the program into all five boroughs, Wohltmann adds.
Some scientists think DOT used on TB patients may be another way to go. Since many communities are already endowed with good support services for HIV patients, some DOT proponents argue, why not recruit volunteers to help supervise therapy? Indeed, a study on the subject of DOT used on AIDS patients found that compliance increased among patients on zidovudine (AZT) as long as supervision was maintained.1
Fans of electronic monitoring point out that it’s much cheaper than providing directly observed therapy. For AIDS patients, with their more complicated regimens, it may be more logistically feasible, they add.
Two companies Apria, and Anderson Clinical Technology in Rolling Meadows, IL produce most of the monitoring systems used today, Blaschke says. The Anderson system employs specially made blister packs that electronically record opening events. Blaschke likes Apria’s MEMS (Medication Event Monitoring System) system best.
Key to the MEMS system is an ordinary-looking bottle cap that contains a microchip that records every bottle-opening event. At night, the patient places the pill bottle on a device that contains a modem. The device is about the size of a paperback novel, and it plugs into the patient’s telephone jack. The device dials an 800 number and feeds its data into a central computer.
When patients sign on with the system, they are interviewed about all their other meds, including alternative treatments, Wohltmann says. A pharmacist reviews the list for possible interactions.
Patients also are interviewed about their lifestyles and schedules. What time do they get up? Do they work? Do they have children? With approval of the patient’s physician, a dosing schedule is developed that suits both the requirements of the drugs and the needs of the patient, says Wohltmann.
Caps can be programmed to beep when it’s time for a dose; in addition, they flash a red warning light if a patient who’s taken all the doses he needs for the day mistakenly attempts to open the pill bottle again. Two displays on the bottle cap show how many doses have already been taken, and how many hours have passed since the last dose, says Wohltmann. The cost for the initial equipment (caps and modem included) is $250; the monthly cost for the system is $69.
Critics at Anderson, APREX’s chief competitor, say the MEMS caps can provide false readings if the bottle cap is twisted the wrong way, and that caps don’t specify which medication has been opened.
Not even manufacturers of the monitoring systems suggest that all AIDS patients need or can use such devices. "We can’t use [them] on the homeless, because our system requires that you have a phone," says Wohltmann. "It’s really only for that small percentage of people who are very challenged in their adherence."
[Editor’s note: For more information on monitoring systems, see Anderson Clinical Technology’s Web site at www.andersonclinical.com, or call the firm at (847) 392-9190. See APREX’S Web site at Aprex.com, or contact the firm by phone at (650) 614-4100.]
Reference
1. Wall TL, Sorenson JL, Batki SL, et al. Adherence to zidovudine (AZT) among HIV-infected methadone patients: a pilot study of supervised therapy and dispensing compared to usual care. Drug Alcohol Dependence 1995; 37:261-269.
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