title: Characterization of physical activity and sitting time among patients on hemodialysis using a new physical activity instrument.
abstract: OBJECTIVE
  Physical activity questionnaires usually focus on moderate to vigorous activities and may not accurately capture physical activity or variation in levels of activity among extremely inactive groups like dialysis patients.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Three dialysis facilities in the San Francisco Bay Area.
  
  
  METHODS
  Sixty-eight prevalent hemodialysis patients.
  
  
  METHODS
  We administered a new physical activity questionnaire designed to capture activity in the lower end of the range, the Low Physical Activity Questionnaire (LoPAQ).
  
  
  METHODS
  Outcome measures were correlation with a validated physical activity questionnaire, the Minnesota Leisure Time Activity (LTA) questionnaire and with self-reported physical function (physical function score of the SF-36) and physical performance (gait speed, chair stand, balance, and short physical performance battery). We also determined whether patients who were frail or reported limitations in activities of daily living were less active on the LoPAQ.
  
  
  RESULTS
  Sixty-eight participants (mean age 59 ± 14 years, 59% men) completed the study. Patients were inactive according to the LoPAQ, with a median (interquartile range) of 517 (204-1190) kcal/week of physical activity. Although activity from the LTA was lower than on the LoPAQ (411 [61-902] kcal/week), the difference was not statistically significant (P = .20), and results from the 2 instruments were strongly correlated (rho = 0.62, P < .001). In addition, higher physical activity measured by the LoPAQ was correlated with better self-reported functioning (rho = 0.64, P < .001), better performance on gait speed (rho = 0.32, P = .02), balance (rho = 0.45, P < .001), and chair rising (rho = -0.32, P = .03) tests and with higher short physical performance battery total score (rho = 0.51, P < .001). Frail patients and patients with activities of daily living limitations were less active than those who were not frail or limited.
  
  
  CONCLUSIONS
  The LoPAQ performed similarly to the Minnesota LTA questionnaire in our cohort despite being shorter and easier to administer.
authors.affiliation: Division of Nephrology, University of California San Francisco and San Francisco VA Medical Center, San Francisco, California; United States Renal Data System Nutrition Special Studies Center, University of California, San Francisco, California. Electronic address: kirsten.johansen@ucsf.edu.
authors.forename: Kirsten L
authors.initials: KL
authors.lastname: Johansen
authors.affiliation: Department of Physical Therapy, University of Utah, Salt Lake City, Utah.
authors.forename: Patricia
authors.initials: P
authors.lastname: Painter
authors.affiliation: Division of Nephrology, University of California San Francisco and San Francisco VA Medical Center, San Francisco, California.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Delgado
authors.affiliation: United States Renal Data System Nutrition Special Studies Center, University of California, San Francisco, California.
authors.forename: Julie
authors.initials: J
authors.lastname: Doyle
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D006435:Renal Dialysis; D057185:Sedentary Behavior; D011795:Surveys and Questionnaires