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C HAP TE R 4 0 / Adherence to Cardiovascular Treatment Regimens 891

Table 40-1 ■ METHODS OF ADHERENCE MEASUREMENT AND FEATURES OF THEIR USE
Measurement Method Behaviors* Advantages Disadvantages
Self-report
Interview All behaviors Inexpensive, provides details Tends to over-report adherence
24-hour recall All behaviors Increased accuracy due to short Under representation of time may increase bias if recall
recall period day is atypical
Questionnaire All behaviors Numerous scales available, Requires literacy; may be lengthy, needs to be sensitive
inexpensive, does not and appropriate to age, gender, reading level, and
influence behavior ethnicity, can be easily distorted
Diaries All behaviors Provides detail of circumstances May influence the behavior, may under- or over-report
of behavior adherence, subject to recall bias if not recording not
done timely, requires cooperation of patient, requires
patient literacy
Biologic outcomes (serum, Medication-adherence, diet, May provide a validation of Are indirect measures of adherence, only measures
urine, or saliva level of smoking cessation behavior adherence close to time of measurement, expensive
drug or its metabolite)
Electronic monitors Medication taking, exercise, Provides detailed pattern of Cost prohibits widespread use, use of the monitoring
(electronic event monitors, smoking cessation, pain adherence, provides data device may influence behavior, requires cooperation
heart rate monitors, control, symptoms, on unsupervised exercise; of patient
accelerometers, SenseWear food intake diaries provide data on
Arm Bands, electronic adherence to recording
diaries: PDAs, glucometers) protocol, record closer to
occurrence of behavior, e.g.
eating, smoking. Results in
decreased recall bias, records
in naturalistic setting
Pill counts Medication taking Inexpensive, easy to conduct Over estimates, does not provide pattern of adherence
Pharmacy records Medication taking Provides another source of Not available universally, requires use of 1 pharmacy,
adherence data, easy to does not provide data on adherence pattern
obtain data

*Medication taking, eating, exercise, smoking cessation.

the visit. However, these tend to provide an overestimation of ad- The AMPM has been shown to provide valid measures of total en-
herence. 35 When comparing self-reported interview adherence to ergy and nutrient intake among healthy normal weight women 38
electronic measured adherence, Dunbar-Jacob et al. 35 found 97% and obese women. 39 Based on the AMPM approach, the Nutri-
adherence reported in the interview compared with 84% adher- tion Data System for Research is a comprehensive software pro-
ence measured by an unobtrusive electronic event monitor. gram available for research purposes for dietary data collection
Assessing dietary adherence requires a determination of what the and analysis through 24-hour dietary recalls, food records, menus,
person eats and the degree to which the food intake approximates and recipes. It also features optional dietary supplement data that
36
the recommended diet. The most widely used and rigorous meas- may be included with 24-hour dietary recalls or food records. This
ure of dietary adherence in population studies is the 24-hour di- software was developed by the Nutrition Coordinating Center at
etary recall, where individuals are asked to recall their food and the University of Minnesota and is updated annually to reflect
beverage intake in the previous day. 37 The recall is conducted marketplace changes and new analytic data. It contains values for
unannounced so that individuals cannot change eating habits in 155 nutrients, nutrient ratios, and food components and includes
anticipation of the recall. This method allows more exact descrip- over 18,000 foods, including ethnic foods and over 8,000 brand
tion of foods (e.g., brands, degree of fat modification) but also re- products (NDSR, 2006 to 2007, University of Minnesota, Min-
quires interviewer skill at prompting recall and eliciting detail. neapolis). Additional software programs are available to collect
Benefits of the 24-hour recall are increased accuracy because of the dietary data, for example, the United States Department of Agri-
shortened recall period and reduced patient burden compared to culture Nutrient Database for Standard Reference (Washington,
recording in a food diary, but a disadvantage is that there may be DC), ProNESSy (Princeton, NJ), and Food Processor (Salem,
increased bias if the recall is conducted for days on which the eat- OR). All these programs provide summarization of dietary data
ing pattern is atypical. 37 To compensate for this weakness, some and detailed reports of macronutrients (carbohydrate, fat) and
studies have multiple 24-hour dietary recalls (from 3 to 7) per- micronutrients (vitamins, minerals).
formed on nonconsecutive days to account for daily variations in Adherence to exercise regimens may also be assessed through
food intake; however, three is most typical. 7-day physical activity recall interviews. One study reported a very
In order to improve accuracy in reporting dietary intake, vari- weak association between the 7-day physical activity recall and the
ous techniques have been employed to help individuals estimate energy expenditure as assessed by doubly labeled water. 40 How-
their intake accurately. One such example includes the United ever, on balance, self-report measures provide the most practical
States Department of Agriculture automated multiple-pass and cost-effective method for assessing adherence. Interviews may
method (AMPM), a five-step multiple-pass 24-hour dietary recall be guided by established questionnaires, for example, the Paffen-
method. 38 It is a computer assisted 24-hour dietary recall de- barger, the Physical Activity Recall, and the Modified Activity
signed to provide better cues for respondents’ cognitive processes. Questionnaire.