The association between severity of King's Obesity Staging Criteria scores and treatment choice in patients with morbid obesity: a retrospective cohort study.

Background: The King's Obesity Staging Criteria (KOSC) comprises of a four-graded set of health related domains. We aimed to examine whether, according to KOSC, patients undergoing bariatric surgery differed from those opting for conservative treatment.

Methods: We graded 2142 consecutive patients with morbid obesity attending our centre from 2005-10 into the following KOSC domains: airway/apnoea, body mass index (BMI), cardiovascular risk (CV-risk), diabetes mellitus, economic complications, functional limitations, gonadal dysfunction, and perceived health status/body image. Both patients and physicians agreed upon treatment choice through a shared decision making process.

Results: A total of 1329 (62%) patients opted for lifestyle intervention and 813 (37%) for bariatric surgery as their first treatment choice. The patients treated with bariatric surgery were younger (42 vs. 44 years,  < 0.001), had a higher BMI (45.4 vs. 43.8 kg/m,  < 0.001) and had a lower ten year estimated CV-risk (9.4 vs. 10.7%,  = 0.004) than the lifestyle intervention group. Compared with having BMI < 40 kg/m, BMI ≥ 40 kg/m was associated with 85% increased odds of bariatric surgery (OR 1.85 [95% CI 1.48, 2.30]). Conversely, patients with ≥20% ten year CV-risk, had lower odds of bariatric surgery than patients with <20% CV-risk (0.68 [0.53, 0.87]).

Conclusion: BMI was the strongest KOSC-domain associated with subsequent bariatric surgery after a shared decision making process. Prospective studies are required to assess whether the use of KOSC can help guide patients and clinicians to identify the most appropriate choice of treatment for morbid obesity.