Measuring Compliance

Summary

  1. Self report Problem is patients overestimate their compliance level.
  2. Therapeutic outcome We can not be sure that the recovery from an illness has been owing to the treatment. It could have been spontaneous, or perhaps the patient is suffering less stress.
  3. Health worker estimates Very unreliable.
  4. Pill and bottle counts Problem is patients can throw the pills away!
  5. Mechanical methods Device for measuring the amount of medicine dispensed from a container. Expensive and not fool-proof.
  6. Biochemical tests Blood tests or urine tests. Accurate, but Expensive, Inconvenient. Urine and blood samples are accurate ways of checking on compliance but a patient could easily take the required dose just before the appointment with the doctor. Also one has to take account of a patients metabolism or biochemical response to the prescribed drugs.

If multiple readings are taken by using several of the methods that check compliance then a more accurate picture of the patients' compliance can be made. If a patient is shown to be non-compliant by several different measures then we can be almost certain that the subject really has not complied.

A treatment that is growing in the UK is oral asthma medication, and measuring adherence rates will help us to measure the effectiveness of the medicines. If people follow the prescribed treatment programme they should reduce the attacks of breathlessness, but many people forget or decline to take the medicine regularly. A study in London used an electronic device (TrackCap) on the medicine bottle which recorded the date and time of each use of the bottle (Chung and Naya, 2000). The patients were told that adherence rates were being measured, but were not told about the details of the TrackCap. The medicine was supposed to be taken twice a day, so a person was seen as adhering to the treatment if the TrackCap was used twice in a day, 8 hours apart. Over a twelve-week period, compliance was relatively high (median 71 per cent), and if the measure was a comparison of TrackCap usages with the number of tablets then adherence was even higher (median 89 per cent).

Another study on asthma medicines, this time inhalers, checked for adherence by telephoning the patient’s pharmacy to assess the refill rate (Sherman et a/., 2000). They calculated adherence as a percentage of the number of doses refilled divided by the number of doses prescribed. This study of over 100 asthmatic children in the USA was able to compare pharmacy records with doctor’s records and with the records of the medical insurance claims for treatment. They concluded that the pharmacy information was over 90 per cent accurate and could therefore be used as basis for estimating medicine use. They also found that adherence rates were generally quite low (for example 61 per cent for inhaled corticosteroids), and that doctors were not able to identify the patients who had poor adherence.

Source

Philip Banyard, 2002, Psychology in Practice – Health, Hodder & Stoughton, ISBN 0-340-84496-5