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. 2009 Nov-Dec;8(6):367-74.
doi: 10.1177/1545109709352884.

A simple single-item rating scale to measure medication adherence: further evidence for convergent validity

Seth C Kalichman  1 , Christina M Amaral, Connie Swetzes, Michelle Jones, Rene Macy, Moira O Kalichman, Chauncey Cherry
Affiliations

A simple single-item rating scale to measure medication adherence: further evidence for convergent validity

Seth C Kalichman et al. J Int Assoc Physicians AIDS Care (Chic). 2009 Nov-Dec.

Abstract

Background: Self-report measures of medication adherence are inexpensive and minimally intrusive. However, the validity of self-reported adherence is compromised by recall errors for missed doses and socially desirable responding.

Method: Examined the convergent validity of 2 self-report adherence measures administered by computerized interview: (a) recall of missed doses and (b) a single-item visual analogue rating scale (VAS). Adherence was also monitored using unannounced phone-based pill counts that served as an objective benchmark.

Results: The VAS obtained adherence estimates that paralleled unannounced pill counts (UPCs). In contrast, self-reported recall (SR-recall) of missed medications consistently overestimated adherence. Correlations with participant characteristics also suggested that the computer-administered VAS was less influenced by response biases than SR-recall of missed medication doses.

Conclusions: A single-item VAS offers an inexpensive and valid method of assessing medication adherence that may be useful in clinical as well as research settings.

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Figures

Figure 1
Figure 1
Frequency distribution for adherence assessed by unannounced pill counts.
Figure 2
Figure 2
Frequency distribution for adherence assessed by self-reported recall.
Figure 3
Figure 3
Frequency distribution for adherence assessed by the visual analogue scale.
See this image and copyright information in PMC

References

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