Validity of the International Fitness Scale (IFIS) and its associations with cardiometabolic health and body composition in adults with type 2 diabetes: A cross-sectional study.

Both IFIS overall and IFIS cardiorespiratory showed graded associations with 6-minute walk test performance in adults with type 2 diabetes.

• Cross-sectional analysis conducted on 282 adults with T2DM (mean age 63.6 ± 8.1 years, 37.9% women).
• ANCOVA models adjusted by sex and age showed p < 0.001 for both IFIS overall and IFIS cardiorespiratory associations with 6MWT.
• Self-reported fitness was assessed using IFIS, including overall, cardiorespiratory, muscular, speed-agility, and flexibility scores.
• Objective cardiorespiratory fitness was assessed using the 6-minute walk test (6MWT) as the criterion measure.

IFIS cardiorespiratory had limited discriminatory ability for identifying performance below the population-predicted mean 6MWT distance.

• IFIS cardiorespiratory showed an AUC of 0.615 (95% CI: 0.552–0.678) for discriminating performance below the population-predicted mean 6MWT distance.
• This AUC value indicates only modest discriminatory performance.
• ROC curves were compared using DeLong tests.

IFIS overall outperformed the 6MWT for predicting poor cardiovascular health in adults with type 2 diabetes.

• IFIS overall AUC for predicting poor cardiovascular health was 0.678 (95% CI: 0.618–0.737).
• 6MWT AUC for predicting poor cardiovascular health was 0.586 (95% CI: 0.517–0.654).
• Cardiovascular health was assessed using a cardiovascular health score.
• AUCs were compared using DeLong tests.

IFIS overall outperformed the 6MWT for predicting metabolic dysfunction-associated steatotic liver disease (MASLD).

• IFIS overall AUC for predicting MASLD was 0.630 (95% CI: 0.563–0.696).
• 6MWT AUC for predicting MASLD was 0.519 (95% CI: 0.443–0.595).
• MASLD was one of the cardiometabolic outcomes examined alongside high-sensitivity C-reactive protein.

Apart from IFIS muscular, all IFIS scores were significantly associated with cardiometabolic and body composition outcomes.

• Cardiometabolic outcomes included cardiovascular health score, MASLD, and high-sensitivity C-reactive protein.
• Body composition outcomes included BMI, visceral adipose tissue volume, and thigh fat-free muscle volume.
• IFIS muscular was the only subscale that did not show significant associations with all cardiometabolic and body composition outcomes.
• ROC analyses showed at least similar predictive performance for IFIS overall and cardiorespiratory fitness scores compared to 6MWT for these outcomes.

The study population consisted of 282 adults with type 2 diabetes mellitus with specific demographic and clinical characteristics.

• Mean age was 63.6 ± 8.1 years.
• 37.9% of participants were women.
• The study used a cross-sectional design.
• Body composition was assessed using visceral adipose tissue volume and thigh fat-free muscle volume, suggesting advanced imaging techniques were employed.