Assessing sensitivity to change of the genomics outcome scale (GOS)

The Genetic Counseling Outcome Scale (GCOS‐24) is a 24‐item patient‐reported outcome measure (PROM) that was developed to evaluate genetic counseling and testing services by measuring the construct of empowerment. The Genomics Outcome Scale (GOS) is a 6‐item version of GCOS‐24 that was designed to provide a PROM for use both within and outside clinical genetics services and reduce respondent burden. However, unlike GCOS‐24, the sensitivity to change of the GOS has not yet been assessed in appropriate clinical settings. We carried out pre‐ and post‐clinic surveys using the GOS to assess sensitivity to change of the GOS and produce before‐and‐after GOS data as part of a service evaluation. The survey was sent to patients attending the genetic counseling clinic for a first appointment at the All Wales Medical Genetic Service from 8 April 2019 to 18 September 2019. Patients attending disease management clinics, where genetic issues were not the primary concern, were excluded from this study. A total of 138 respondents were included in the final analysis. The result shows that empowerment scores, measured using the GOS, were significantly higher (p<0.05) after clinic attendance. The GOS shows good sensitivity to change, with a medium‐to‐large effect size (Cohen’s d = 0.73). The result also shows that the service is delivering measurable benefits for its service users.


| INTRODUC TI ON
Patient-reported outcome measu (PROM) are increasingly implemented in healthcare systems to evaluate the effectiveness and quality of care (Meadows, 2011). The Genetic Counseling Outcome Scale (GCOS-24) is a 24-item PROM that was developed to evaluate genetic counseling and testing services (McAllister et al., 2011).
GCOS-24 was designed to measure the construct of empowerment, comprising five sub-dimensions of outcomes valued by patients: cognitive, decisional and behavioral control, emotional regulation, and hope (McAllister et al., ,2010(McAllister et al., , , 2011. Each item on the GCOS-24 is rated on a 7-point Likert scale (1 = strongly disagree, 7 = strongly agree) (McAllister et al., 2011). Scores range from 24 to 168 with higher scores indicating higher levels of empowerment (McAllister et al., 2011).  has been demonstrated to have good test-retest liability, sensitivity to change, and construct validity. (McAllister et al., 2011) GCOS-24 has been translated into Danish, Spanish, Dutch, and Brazilian Portuguese (Diness et al., 2017;Muñoz-Cabello et al., 2017;Segundo-Ribeiro et al., 2020;Voorwinden et al., 2019). It is used extensively in clinical and research settings in both the UK and internationally. GCOS-24 was used in six of the 25 UK regional clinical genetics service in 2011-12 as part of a service evaluation exercise (McAllister, 2016). It has also been used to evaluate specialist genetic services, including psychiatric, cardiovascular, and cancer genetic services (Inglis et al., 2015;Ison et al., 2019;Yuen et al., 2020). This study aims to (a) assess sensitivity to change of GOS and (b) provide before-and-after GOS data to the NHS All Wales Medical Genetics Service (AWMGS) as part of a service evaluation.
AWMGS is a clinical genetics service offering genetic counseling and testing in families where a genetic condition is suspected or known to be present, including autosomal dominant, recessive and X-linked conditions, learning disability, chromosome abnormalities, and developmental delay. Patient may be seen by a clinical geneticist or a genetic counselor. Previous research has demonstrated that patients attending AWMGS experience increased level of empowerment following clinic attendance, as captured by GCOS-24 (Costal Tirado et al., 2017), and so we would expect that if GOS is sensitive to changes in empowerment, that GOS would also capture increased level of empowerment amongst patients after AWMGS clinic atten- were given a new pre-appointment GOS at the clinic to fill in on the spot. All patients completing and returning a pre-appointment GOS ( Figure 1) were sent a post-appointment GOS together with a replypaid envelope 4 weeks after clinic attendance. Patients attending disease management clinics, where genetic issues were not the primary concern, were excluded from this study.
Unfortunately, it has not been possible to calculate a participation rate or a completion rate. This is because there are so many locations across Wales in which clinics are held, with some in use every day and others only once per 1-2 months, and they have different secretarial and administrative staff involved. Practices have therefore diverged in terms of the proportion of patients given the questionnaires at each stage.
The before-and-after GOS data were inserted into a Microsoft Excel spreadsheet. The data were then analyzed using a paired samples t-test with IBM SPSS. After reversing the score for Question 3, the score of all six items was added up to provide a total empowerment score. We tested a hypothesis that empowerment scores would be significantly higher after clinic attendance. If the null hypothesis were rejected, this would show sensitivity to change of the F I G U R E 1 The genomics outcome scale (GOS) GOS. The effect size of the GOS was calculated using Cohen's d for- A total of 138 paired GOS questionnaires were collected for this study. Of the 138 paired questionnaires, 20 had incomplete data and were excluded from further analysis.
The mean empowerment scores pre-and post-clinic were 20.11 and 23.08, respectively (See Figure 2). This study shows that empowerment scores increased by an average of 2.97 points after the appointment. Post-appointment scores tend to be distributed more on the high end of the scale compared to pre-appointment scores.
To determine if empowerment scores pre and post-appointment were significantly different, we conducted a paired samples t-test with the p-value threshold for statistical significance set at 0.05.
As the p-value was 0.000, we conclude that empowerment scores were significantly higher after clinical attendance (See Table 1). The null hypothesis was rejected in favor of the alternative hypothesis.
Cohen's d was calculated to be d = 0.73, demonstrating a mediumto-large effect size. Figure 4 demonstrates an increase in the average score of each item on the GOS, except Question 3. We further analyzed the data by performing a paired samples t-test for each individual item on the GOS. Whilst GOS has been designed to generate a total scale score, item-level data were requested by AWMGS as part of this service evaluation. This follows the earlier experience gained by AWMGS of a service evaluation using GCOS-24, which found that patients achieved significant improvement in post-appointment scores for most GCOS-24 items except for those items designed to capture emotional regulation.
This supported the clinical team to reflect upon their practice and consider areas where practice improvements could be made to maximize patient benefits. (Costal Tirado et al., 2017). Corrections for multiple comparisons were made using the Benjamini-Hochberg method (Bejamini & Hochberg, 1995, see Table 1). By setting the p-value threshold for statistical significance at 0.05, Table 1 shows that the post-clinic scores were significantly higher for all items, except Question 3 (When I think about the condition in my family, I get upset).
Post-appointment empowerment scores were significantly higher than pre-appointment empowerment scores with an average increase of 3.26 points. This study has shown good sensitivity to change of GOS, with a medium-to-large effect size and some evi-  There were some important limitations to this study. Firstly, the extent to which the GOS survey was completed by all eligible patients is unknown. Whilst this is an important limitation, it does not significantly weaken the study findings because an adequate number of responses were collected to enable assessment of sensitivity to change of GOS. The study was also geographically limited to Wales, so the findings may not be reflective of genetic counseling services in other parts of the UK or internationally.
This study was also conducted purely in a clinical genetics setting. As the GOS is designed to be used in both clinical genetics settings and in other clinical specialties or research contexts where genetic counseling and / or testing are offered, it will be

ACK N OWLED G EM ENTS
Dr. Melanie Myers served as Action Editor on the manuscript review process and publication decision. The authors thank the patients who agreed to participate in this survey and the clinical staff who contributed to data collection.

CO N FLI C T O F I NTE R E S T
The authors have no conflict of interest to declare.

A N I M A L S TU D I E S
No non-human animal studies were carried out by the authors of this article.

DATA AVA I L A B I L I T Y S TAT E M E N T
Data available on request from the authors: The data that support the findings of this study are available from the corresponding author upon reasonable request.