The Genetic Counselling Outcome Scale (GCOS-24):

A new questionnaire to measure outcomes from clinical genetics services

What is it for?

An enduring challenge in clinical genetics and genetic counselling is how best to measure patient benefit. It has been difficult, historically, to demonstrate whether or not genetic counselling / testing provided measurable benefits to patients in clinical genetics. Patient Reported Outcome Measures (PROMs) offer a possible solution. PROMs are short self-completion questionnaires that capture aspects of patient health or health-related quality of life (HRQL). PROMs are used

  • in research to evaluate patient benefits from new interventions, for example in randomised controlled trials (RCTs)
  • for service evaluation in routine clinical practice.

Currently, health policy in the UK, the US and elsewhere encourages use of PROMs data. However, in clinical genetics, there is no agreement about the best PROMs to use. The Genetic Counselling Outcome Scale (GCOS-24) was developed to fill this gap, and is based on the findings from a research programme conducted in Manchester (UK) that began in 2003, and involved a mixed methods approach (systematic literature review, Delphi survey, qualitative interviews and focus groups with patients and genetics clinicians). The GCOS-24 was developed from extensive qualitative data, and has been shown to

  • have high internal consistency (α=0.87) and test-retest reliability (r = 0.86)
  • have concurrent validity with health locus of control, satisfaction with life, depression, and authenticity and
  • capture statistically significant patient benefit following attendance at a genetic counselling clinic (d=0.7).

These properties suggest that the GCOS-24 is an appropriate validated PROM to evaluate genetic counselling and testing interventions:

  • in research:
    • to compare new interventions with standard care to evaluate which provides greatest patient benefit (e.g. in Randomised Controlled Trials (RCTs))
  • in clinical practice:
    • to generate evidence of patient benefit
    • to compare performance of different services.