Abstract
Background: Within home-based rehabilitation, patient adherence to the prescribed intervention is vital to maximise functional outcomes and to assess whether treatments effects are dose-dependent. However, adherence measurement methods are limited. This thesis aimed to 1) evaluate currently used measurement methods and select one for further development, 2) explore mechanisms for optimising this measure and 3) evaluate the effects of optimisation.Methods:
1) Systematic review: Eight named methods were reviewed across 222 measurement property assessments. Adherence diaries were widely used, variable in their completion and validity and could be developed through better understanding their successful utilisation. 2) Multiple case study: Seven UK allied health professional rehabilitation trials were studied to develop a theoretical model of diary success. 3) Randomised crossover trial (RCT): Selected diary model components were used to develop an optimised diary and a non-optimised diary (impaired according to the same model components), which were compared in a crossover trial for their validity in assessing adherence to walk duration against an Activpal accelerometer. Healthy older adults (n=32) undertook an eight week walking program and recorded walk duration and frequency in the two diaries for four weeks each. Secondary outcomes included test-retest reliability and acceptability.
Results: Within the RCT, optimised and non-optimised diaries did not significantly differ in their validity, reliability or acceptability. Both closely matched the Activpal when assessing percentage adherence to duration, but the limits of agreement (LOA) were wide (optimised diary = mean difference 3.09% (95% LOA -103% to 110%), non-optimised diary = -0.34% (-131% to 131%), p=0.732). Narrower LOA were observed for the validity of percentage of days adhered and reliability. Participants considered both diaries a low burden. Equal numbers favoured each diary or had no preference. Preference had little effect on validity.
Conclusion: Different adherence diary designs can be used interchangeably when collecting similar information. Using diaries in clinical practice is inadvisable as individual-level diary data is likely to be inaccurate. Sample level diary data (e.g. summaries or group change) is likely to be valid. Validity appears to depend upon activity and trial characteristics rather than preferences. These findings are based on healthy, highly educated older adults and need confirming in other populations. In the right situations, diaries are a valuable adherence measurement tool and collect valid and complete data.
| Date of Award | 2015 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Brian Williams (Supervisor), Marian Brady (Supervisor) & Doreen McClurg (Supervisor) |