Does the National Bariatric Prioritization Tool predict health outcomes?

Abstract

Background: The National Bariatric Prioritization Tool (NBPT), developed in Aotearoa New Zealand (AoNZ), has not been validated using real patient data. The aim was to determine the predictive validity of the NBPT on health outcomes.

Methods: An observational study was undertaken of consecutive patients undergoing elective bariatric surgery at Middlemore Hospital using the NBPT from December 2014 to December 2016. The primary outcome was the correlation between prioritization score and percentage total weight loss (%TWL) at 18 months follow-up, with secondary outcomes being correlation with change in HbA1c, lipids, resolution of OSA, resolution of hypertension, and reduction in arthritis medications. Equity of access was measured by the relationship to age group, gender and ethnicity.

Results: There were 294 patients included. There was no correlation between %TWL and prioritization score (correlation -0.09, P = 0.14). The benefit score correlated with %TWL (correlation 0.25, P < 0.0001). There were correlations between prioritization score and HbA1c reduction (correlation 0.28, P < 0.0001), resolution of OSA (correlation 0.20, P < 0.001) and resolution of hypertension (correlation 0.20, P < 0.001). There was a significant difference in prioritization score based on ethnicity, with Māori and Pasifika scoring higher than New Zealand European (P = 0.0023).

Conclusions: While the NBPT does not correlate with %TWL, it may have predictive validity through correlations with improvement of comorbidities such as diabetes, OSA and hypertension. Given higher rates of obesity and comorbidities in Māori and Pasifika, the higher scores may suggest the tool may be used to achieve equity of access. Further modifications should be considered to optimize outcomes.

Keywords: bariatrics; equity; prioritization.