Physical activity and mortality in chronic kidney disease (NHANES III).
OBJECTIVE
Chronic kidney disease (CKD) is associated with impaired physical activity. However, it is unclear whether the associations of physical activity with mortality are modified by the presence of CKD. Therefore, we examined the effects of CKD on the associations of physical activity with mortality.


METHODS
This was an observational study of 15,368 adult participants in the National Health and Nutrition Examination Survey III; 5.9% had CKD (eGFR < 60 ml/min per 1.73 m(2)). Based on the frequency and intensity of leisure time physical activity obtained by a questionnaire, participants were divided into inactive, insufficiently active, and active groups. Time to mortality was examined in Cox models, taking into account the complex survey design.


RESULTS
Inactivity was present in 13.5% of the non-CKD and 28.0% of the CKD groups (P < 0.001). In two separate multivariable Cox models, compared with the physically inactive group, hazard ratios (95% confidence intervals) of mortality for insufficiently active and active groups were 0.60 (0.45 to 0.81) and 0.59 (0.45 to 0.77) in the non-CKD subpopulation and 0.58 (0.42 to 0.79) and 0.44 (0.33 to 0.58) in the CKD subpopulation. These hazard ratios did not differ significantly between the CKD and non-CKD subpopulations (P > 0.3).


CONCLUSIONS
Physical inactivity is associated with increased mortality in CKD and non-CKD populations. As in the non-CKD population, increased physical activity might have a survival benefit in the CKD population.
Beddhu
Srinivasan
S
VA Healthcare System, Salt Lake City, UT 84112, USA. Srinivasan.beddhu@hsc.utah.edu
Baird
Bradley C
BC
Zitterkoph
Jennifer
J
Neilson
Jill
J
Greene
Tom
T
D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D051436:Renal Insufficiency, Chronic / Q000401:mortality* / Q000503:physiopathology*; D012307:Risk Factors; D057185:Sedentary Behavior