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Education Materials > Publications > Improving Patients Adherence to TB Treatment > Assessing for Adherence

Improving Patient Adherence to Tuberculosis Treatment (1994)

Assessing for Adherence

Section Topics

Health care providers often do not know that a patient is not following recommendations. It is very important for you to determine whether your patients are taking medications as prescribed. Your first responsibility is to be aware of the general problem of nonadherence and to have a high index of suspicion. Consider several methods for assessing adherence.

Indirect Methods

Ask the patient. Talking with the patient can be an effective way to estimate adherence. It may be useful to simply ask your patient whether he or she will be able or willing to take medications for the prescribed time. Patients who admit that they may not be adherent are often likely to discuss barriers to adherence and ways of overcoming them. Do this periodically in a nonthreatening but direct manner. Address incorrect medicine taking so that patients aren't afraid to tell the truth. For example, you might try one of the following questions (14-17):

People often have difficulty taking their pills for one reason or another. Have you had any difficulty taking your pills?

Many patients find it difficult to take their medication as their doctors say they should. Over the past [insert period of time], do you think you have taken your medicine as you should, on schedule and regularly?

In general how often do you take the pills? In the past [insert period of time], was there any time you missed taking your pills for more than one day?

Communicate effectively. It is best to use an information-intensive style in which you ask for very specific information and also give your patient the opportunity to show his or her knowledge. Using this style, you create open interaction between you and the patient (17). Here is an example of an adaptation of this style:

Health Care Worker (HCW): How many pills do you take a day?

Patient (P): Of what?

HCW: The isoniazid.

P: Yeah, the INH. One in the morning.

HCW: Okay, and what about the rifampin? The red pills?

P: I take the red pills two times a day.

HCW: You take one pill once a day, don't you?

P: No, one pill two times a day.

HCW: You need to take the red pills once a day.

P: Oh, I'd better check that because I've been taking them more often.

This style should reveal information about adherence and should also help to uncover problems in the patient's understanding of the regimen.

Help the patient remember. People tend to forget and to underreport events relating to their health. Encourage the patient to discuss his or her experiences with adherence and what seems to cause problems. Ask for specific information:

  • how often the patient takes medication
  • the number of doses taken
  • how the patient remembers to take the medication
  • whether the patient has problems with the medications

Be sure to listen carefully and tell the patient that the information he or she tells you is very important. Ask the patient to agree to remember and report any problems with taking the medications.

Monitor pills and appointments. Asking patients to bring their medicines for pill counts and monitoring appointment keeping, medication refill, and pickup are other ways of assessing for adherence. However, be aware that if patients wish to avoid appearing nonadherent, they may forget to bring their pill bottles, discard medications, attend clinic but still fail to take their medications, or pick up medicines that they never use.

Check the patient's response to therapy. Another indirect method of assessing adherence is to determine how well your patient is responding to therapy by asking yourself:

  • Has the patient's sputum result improved or converted to negative?
  • Does the chest film indicate improvement?
  • Have the TB signs and symptoms improved or disappeared?

However, response to therapy cannot be used as the sole method of assessing adherence.

  • Several weeks or months may elapse between the initiation of therapy and the discovery that sputum conversion has not occurred or that the chest radiograph does not show improvement. In the meantime, transmission of infection may continue, drug-resistant organisms may emerge, or serious complications may develop.
  • Factors other than nonadherence, such as drug resistance, can lead to a poor therapeutic outcome.
  • A patient who does not adhere to treatment may take enough drugs to become culture negative, but not enough to prevent treatment failure or relapse several weeks or months later.

Direct Methods

Test urine for metabolites. One of the direct methods for assessing adherence is to detect the presence of TB drugs or their metabolites in a sample of the patient's urine. The limitation of these tests is that they show only recent ingestion of medication (within the past 24 to 48 hours). They cannot be used to measure an ongoing pattern of adherence. In addition, they are influenced by the patient's rate of metabolizing the medication.

Commercial "dipsticks" can be used for detecting isoniazid (INH) metabolites in the urine. A test for the presence in the urine of rifampin (RIF) or its metabolites is examination of the color of the urine. In most patients, RIF turns urine, saliva, sweat, and tears an orange-red color. A quick glance at a urine specimen reveals whether the patient has recently taken this medication.

Directly observe the patient. Directly observing your patient swallow each dose of medication is an effective method of assessing for adherence (see Give Directly Observed Therapy).


Released October 2008
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination -

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