Table 2.

Description of the commonly used quality of life assessment tools and how to interpret their scores

Tool	Components	Scoring and clusters	Overall score	Interpretation of results
Reflux disease specific questionnaires
QOLRAD	A total of 25 questions making up 5 dimensions  Emotional distress (6 items)  Sleep disturbance (5 items)  Food or drink problems (six items)  Physical or social functioning (five items)  Vitality (three items)	Each question is awarded a maximum score of 7 and patients are asked to rate the symptoms they have experienced over the preceding week on a 7-point scale	The total score for each domain is then calculated as an average of the total number of questions in each domain. The overall total score is the average of 25 questions	A higher score indicates better QoL
GERD-HRQL	A total of 10 items: 6 items measure satisfaction with degree of heartburn symptoms, two measure dysphagia or odynophagia and one assesses the impact of medication on daily life. The final item measures overall QoL	Each of the ten items is given a score out of 5, whereby 5 is for poor symptom control or satisfaction	The maximum score possible is 45. Composite responses are grouped as excellent (0-5), good (6-10), fair (11-15) and poor (15)	A higher score reflects worse patient symptoms and QoL
Questionnaires specific for gastrointestinal tract
GIQLI[16]	A total of 36 items scored on a 5-point Likert scale[49]	Score range can be between 0 and 144	A maximum score of 144	A higher score indicates better QoL[16]
GSRS	A total of 15 items with 5 dimensions  Reflux,  Abdominal pain,  Indigestion,  Diarrhoea  Constipation	Each question is rated on a 7-point scale	1 represents absence of troublesome symptoms and 7 represents very troublesome symptoms	A higher score indicates poorer QoL
Generic questionnaires
SF-36	A total of 36 items measured over 8 multi-item dimensions: PF, RP, BP, GH, VT, SF, RE and MH	All questions scored on a scale of 0-100, where 100 represents the highest level of functioning possible. A final score of each of the eight dimensions is obtained from averaging the scores The scores form two clusters resulting in total scores for physical and mental health summary measures. PF, RP, BP and GH contribute to the final PCS score. VT, MH, RE and SF form the MCS score	0-100	Norm-based scoring, where mean is standardised to 50. A score higher than 50 indicates better functioning and a score of 100 would indicate the highest possible level of functioning
SF-12[50]	A total of 12 items and a practical version of SF-36. This uses the same eight domains as SF-36	PCS and MCS scores calculated using the scores from the 12 questions	0-100	Norm-based scoring, where mean is standardised to 50. A score higher than 50 indicates better functioning and a score of 100 would indicate the highest possible level of functioning

GERD-HRQL: Gastro-Oesophageal Reflux Disease-Health-Related Quality of Life, QOLRAD: Quality of Life in Reflux and Dyspepsia, QOL: Quality of life, GIQLI: Gastrointestinal Quality of Life Index, SF: Short Form health surveys, GSRS: Gastrointestinal Symptom Rating Scale, MCS: Mental component summary, PCS: Physical component summary, PF: Physical functioning, RP: Role-physical, BP: Bodily pain, GH: General health, VT: Vitality, SF: Social functioning, RE: Role-emotional, MH: Mental health, n/a: Not available