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By-Band-Sleeve study

By-Band-Sleeve study uses EQ-5D-5L HRQOL scoring instrument

The By-Band-Sleeve study is a randomised control trial comparing laparoscopic Roux-en-Y gastric bypass, adjustable gastric band surgery and laparoscopic sleeve gastrectomy

Researchers from the By-Band-Sleeve study have recommended the use of the EQ-5D-5L scoring instrument to measure health-related quality of life (HRQOL) in bariatric surgery patients in combination with a mental health specific instrument. Although, they acknowledge that future work should explore in more detail the association between HRQOL and obesity specific parameters.

In the paper, ‘The EQ-5D-5L is a valid approach to measure health related quality of life in patients undergoing bariatric surgery’, published in PlosONE, the researchers from the University of Cambridge, Cambridge, University of Bristol, Bristol and the University of Oxford, Oxford, UK - writing on behalf of the By-Band-Sleeve Study Management Group - undertook a psychometric validation of the 5 level EQ-5D (EQ-5D-5L) using clinical trial data to measure HRQOL in patients with severe and complex obesity undergoing bariatric surgery.

Health-related quality of life was assessed at baseline and six months later in 189 patients from the By-Band-Sleeve randomised controlled trial. Patients completed two generic health-related quality of life instruments, the EQ-5D-5L and SF-12, which were used together for the validation using data from all patients in the trial as the trial is ongoing. The By-Band-Sleeve study is a randomised control trial comparing laparoscopic Roux-en-Y gastric bypass, adjustable gastric band surgery and laparoscopic sleeve gastrectomy.

The researchers separated patients into four groups: (a) those with a BMI<50 compared to BMI≥50, and (b) those with any comorbidities (type I and/or type II diabetes, presence of obstructive sleep apnoea, New York Heart Association (NYHA) class II-IV, and unable to climb 3 flights of stairs), compared to those without. Subsequently, the authors hypothesised that patients BMI≥50 would have poorer HRQOL scores than patients BMI<50, and those with comorbidity pre-surgery would have greater improvement in their HRQOL following surgery than those without comorbidity.

Outcomes

In total, 189 patients were included in the study, 141 (75%) were female and the median age was 49 years old (range 23–70 years). The BMI ranged from 33–70 and the median weight was 131kg and 65 patients (34%) had a BMI≥50. Seventy-three patients (39%) had diabetes, 94% of whom were receiving medication. Forty-eight patients (25%) had obstructive sleep apnoea and most were receiving airway pressure treatment for the condition. Few of the patients (14%) had a diagnosis of cardiac disease (NYHA class II-IV). Hundred-two patients (54%) reported difficulty climbing one flight of stairs or less without resting.

The researchers report that both the EQ-5D and SF-12 HRQOL scores improved from baseline to six months. The baseline average utility weight for the EQ-5D Index was 0.73±0.25, which increased to 0.76±0.25 six months after randomisation. However, unlike the SF-12, the authors stated that EQ-5D can be affected by a ceiling effect with a slightly higher proportion of patients reporting perfect health (maximum score) at six months after randomisation (21%) than at baseline (12%). The mean EQ-VAS score increased from 62±21 at baseline to 71±21 at six months after randomisation.

The EQ-VAS and the SF12-PHC were also able to discriminate by BMI (<50 vs ≥50 kg/m2; t tests EQ-5D p=0.23, EQ-VAS p=0.03, SF-12 PHC p=0.02, SF-12 MHC p=0.64). When assessing HRQOL change scores by comorbidity (as previously defined) vs no comorbidity, neither questionnaire was able to discriminate between those with and without any comorbidities (t tests EQ-5D p=0.52, EQ-VAS p=0.74, SF-12 PHC p=0.84, SF-12 MHC p=0.26).

The highest degree of correlation were between the EQ-5D pain/discomfort and SF-12 bodily pain domain (r=-0.82). Correlations of greater than or equal to 0.50 were considered as strong. For example, there was a strong negative correlation between EQ-5D mobility and SF-12 domains physical functioning (r=-0.68).

According to the authors, the direction and degree of correlation between the different HRQOL components, except for the SF-12 MHC, were strong (Table 3). The ED-5D Index is most strongly correlated with the SF-12 PHC (r=0.75).

Table 3: Correlations health related quality of life measures overall scores and domains, at baseline (n=189)

Between baseline and 6 months after randomisation, both HRQOL measures showed statistically significant improvements (t tests, EQ-5D p=0.01, EQ-VAS p<0.01, SF-12 PHC p<0.01, SF-12 MHC p<0.01), there was also a mean reduction in bodyweight of 20±14 kg (n=170).

“There were significant improvements in the distribution of responses in all EQ-5D dimensions after surgery and the EQ-5D domains were appropriately correlated with the SF-12, confirming criterion validity,” the authors stated. “The EQ-5D is, therefore, recommended as a generic measure of HRQOL to be used in all trials evaluating surgery for severe and complex obesity.”

“Future, and large enough studies, evaluating the impact of bariatric surgery, might analyse subgroups based on the type, presence and severity of a mental health condition, as the EQ-5D is able to discriminate between severities and changes over time,” the authors conclude. “This might improve the ability of the EQ-5D-5L to capture change in mental health status. Until then we recommend the use of the EQ-5D-5L in combination with a mental health specific instrument. Also, we have not been able to demonstrate the ability to discriminate between groups based on BMI.”

To access this paper, please click here

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