Autor:innen:
Miriam Kemmer, Berlin (Germany)
Christoph U. Correll, Berlin (Germany)
Tobias Hofmann, Berlin (Germany)
Andreas Stengel, Berlin (Germany)
Julia Grosser, Berlin (Germany)
Verena Haas, Berlin (Germany)
Background: Altered physical activity (PA) affects weight recovery in anorexia nervosa (AN) patients.
Study aims: To objectively characterize PA patterns and their effect on weight trajectories in adolescent AN patients.
Methods: PA was assessed in 47 adolescent AN patients on admission to inpatient treatment, and again 4 weeks after discharge (follow-up, FU), and in 20 adolescent healthy controls (HCs) using the Sense Wear™ armband. Four PA categories were defined by metabolic equivalent (MET) ranges: sedentary behavior (SB), light (LPA), moderate (MPA), vigorous (VPA) and high level PA (HLPA, MPA+VPA).
Results: Overall, SB in AN patients was similar, but LPA was significantly higher than in HCs (median LPA on admission, 103 vs. 90 min/d, p= 0.008; FU: 90 vs. 55 min/d, p=0.006). On admission, MPA in AN was significantly lower (77 vs. 122 min/d, p=0.009), and at FU VPA was higher (13 vs. 2 min/d, p=0.039) than in HCs. LPA in AN decreased over time (p=0.008), but the subgroup of patients with high admission LPA continued to express elevated LPA at FU (p=0.047). In patients with high LPA on admission, inpatient BMI percentage change (ΔBMI%) was significantly higher vs. patients exhibiting low LPA at admission (18.2±10.0% vs. 12.0±9.7%, p=0.037), but ΔBMI% between discharge and FU was significantly lower (-2.3±3.6% vs. 0.8 ±3.6%, p= 0.045). HLPA at baseline was associated with a lower inpatient ΔBMI% (p=0.045). No significant direct association between any of the PA parameters at admission and FU BMI was found.
Conclusion: Elevated LPA in AN patients decreased after inpatient treatment, and PA patterns had an impact on weight trajectory. Future studies should be conducted in outpatient settings and investigate whether increased LPA is a state or a trait marker in AN patients.