Test-retest Reliability and Construct Validity of the Satisfaction with Treatment Result Questionnaire in Patients with Hand and Wrist Conditions: A Prospective Study
Authors: De Ridder Willemijn A. , van Kooij Yara E. , Vermeulen Guus M. , Slijper Harm P. , Selles Ruud W. , Wouters Robbert M. ,   , and the Hand-Wrist Study Group
Published: May 2021

Abstract

Background
A patient’s satisfaction with a treatment result is an important outcome domain as clinicians increasingly focus on patient-centered, value-based healthcare. However, to our knowledge, there are no validated satisfaction metrics focusing on treatment results for hand and wrist conditions.

Questions/purposes
Among patients who were treated for hand and wrist conditions, we asked: (1) What is the test-retest reliability of the Satisfaction with Treatment Result Questionnaire? (2) What is the construct validity of that outcomes tool?

Methods
This was a prospective study using two samples: a test-retest reliability sample and a construct validity sample. For the test-retest sample, data collection took place between February 2020 and May 2020, and we included 174 patients at the end of their treatment with complete baseline data that included both the primary test and the retest. Test-retest reliability was evaluated with a mean time difference of 7.2 ± 1.6 days. For the construct validity sample, data collection took place between January 2012 and May 2020. We included 3742 patients who completed the Satisfaction with Treatment Result Questionnaire, VAS, and the Net Promotor Score (NPS) at 3 months. Construct validity was evaluated using hypothesis testing in which we correlated the patients’ level of satisfaction to the willingness to undergo the treatment again, VAS scores, and the NPS. We performed additional hypothesis testing on 2306 patients who also completed the Michigan Hand Outcomes Questionnaire (MHQ). Satisfaction with the treatment result was measured as the patients’ level of satisfaction on a 5-point Likert scale and their willingness to undergo the treatment again under similar circumstances.

Results
We found high reliability for level of satisfaction measured on Likert scale (intraclass correlation coefficient 0.86 [95% CI 0.81 to 0.89]) and almost-perfect agreement for both level of satisfaction measured on the Likert scale (weighted kappa 0.86 [95% CI 0.80 to 0.91]) and willingness to undergo the treatment again (kappa 0.81 [95% CI 0.70 to 0.92]) of the Satisfaction with Treatment Result Questionnaire. Construct validity was good to excellent as seven of the eight hypotheses were confirmed. In the confirmed hypotheses, there was a moderate-to-strong correlation with VAS pain, VAS function, NPS, MHQ pain, and MHQ general hand function (Spearman rho ranged from 0.43 to 0.67; all p < 0.001) and a strong to very strong correlation with VAS satisfaction and MHQ satisfaction (Spearman rho 0.73 and 0.71; both p < 0.001). The rejected hypothesis indicated only a moderate correlation between the level of satisfaction on a 5-point Likert scale and the willingness to undergo the treatment again under similar circumstances (Spearman rho 0.44; p < 0.001).

Conclusion
The Satisfaction with Treatment Result Questionnaire has good-to-excellent construct validity and very high test-retest reliability in patients with hand and wrist conditions.

Clinical Relevance
This questionnaire can be used to reliably and validly measure satisfaction with treatment result in striving for patient-centered care and value-based healthcare. Future research should investigate predictors of variation in satisfaction with treatment results.