Background/Purpose: There is a trend of younger gout onset related to higher obesity prevalence. BMI is limited to discriminate between fat and lean mass. Body composition (BC) analysis is an alternative tool to assess metabolic status. We aimed to investigate the characteristics of BC in early and late onset gout patients.

Methods: Consecutive gout patients who fulfilled the 2016 ACR/EULAR classification criteria were recruited between June 2017 and May 2018. BC was assessed by bioelectric impedance analysis. General obesity was classified by BMI¡Ý28 kg/m². Central obesity was defined as a waist-hip ratio (WHR) above 0.90 for males and above 0.85 for females. The patients with gout onset before age 30 years were defined as early-onset group while the others were defined as late-onset group.

Results: Among 230 gout patients recruited, mean age was 42.3 with standard deviation 22 years. Mean serum uric acid (sUA) was 9.2 with standard deviation 2.1mg/dl and 40 (17.4%) patients presented tophi. The prevalence of general obesity and central obesity was 23.4% and 64.8%, respectively. There were 91 (39.5%) patients in early-onset group. Late-onset group (n=149) showed lower prevalence of general obesity than early-onset group [25 (16.7%) vs. 29 (31.8%), P=0.017] but higher prevalence of central obesity [99 (71.2%) vs. 50 (54.9%), P=0.016]. Among obese gout patients, late-onset group showed lower estimated glomerular filtration rate (eGFR), higher prevalence of hypertension and diabetes mellitus, WHR without significant difference in other BC indicators compared with early-onset group (Table 1). Among non-obese gout patients, late-onset group presented significantly lower level of sUA and eGFR, higher prevalence of hypertension and metabolic syndrome compared with early-onset group (P<0.05, Table 1). Non-obese late-onset gout patients exhibited higher WHR, central obesity, total fat percentage and trunk fat percentage (P<0.05, Table 1) although there were no significant difference of BMI and prevalence of overweight between the two groups.

Conclusion: There were more BMI defined obese patients in early-onset gout patients but non-obese late-onset gout patients showed more central obesity and fat percentage without difference in BMI compared with non-obese early-onset gout patients.

Acknowledgement: The present study was supported by Guangdong Natural Science Foundation, China (Grant no. 2014A030310086).