透析患者の身体活動と栄養指標の関連

透析患者の身体活動と栄養指標の関連を調査した論文を紹介します。

Cupisti A, Capitanini A, Betti G, D'Alessandro C, Barsotti G: Assessment of habitual physical activity and energy expenditure in dialysis patients and relationships to nutritional parameters. Clin Nephrol. 2011 Mar;75(3):218-225.

透析患者とコントロールで、身体活動、エネルギー消費量、栄養指標を比較検討しました。身体活動については、透析患者では平均METsが有意に低く（1.3対1.5）、3Mets以上の活動の時間が短く（89分対143分）、1日の歩数が少なく（5584歩対11735歩）、その結果としてエネルギー消費量が低い（2190kcal対2462kcal）という結果です。

エネルギー摂取量も有意に少ない（26.1kcal対32.4kcal）という結果です。多変量解析ではエネルギー摂取量と蛋白質摂取量は独立して身体活動の強度と関連していました。

以上より透析患者では身体活動量が低いこと、運動と栄養に関連を認め、これらが生命予後、リハ、QOLと関連してくると結論付けています。

横断研究なので因果関係については不明ですが、運動量が多い透析患者は食事量が多いといえます。運動介入することで食欲、食事摂取量が増すという仮説はありうると思いますが、要検証です。その際、透析患者では栄養障害や悪液質の方も少なくないので、運動強度も要検討です。

Abstract
Background and aim: Assessment of physical activity level and of energy expenditure is important in the clinical and nutritional care of dialysis patients, but it is not so easy to accomplish. The SenseWear™ Armband (SWA) is a novel multisensory device that is worn on the upper arm and collects a variety of physiologic data related to physical activity. Thus, duration and intensity of physical activity is recorded and expressed as METs (Metabolic Equivalent Task), and energy expenditure is estimated. The aim of our study was to assess interdialytic spontaneous physical activity in stable chronic hemodialysis (HD) patients and the relation to nutritional status and dietary nutrient intake.

Patients and methods: In 50 stable patients on maintenance hemodialysis treatment and 33 normal subjects (control group), level of spontaneous physical activity and estimated daily energy expenditure was assessed by SWA and related to biochemistry and anthropometry data, bioelectric impedance vector analysis, and energy and nutrient intake information coming from a 3-day food recall.

Results: In respect to controls, HD patients showed lower mean daily METs value (1.3 ± 0.3 vs. 1.5 ± 0.2, p < 0.01), a lower time spent on activities > 3 METs (89 ± 85 vs. 143 ± 104 min/day, p < 0.05), lower number of steps per day (5,584 ± 3,734 vs. 11,735 ± 5,130, p < 0.001), resulting in a lower estimated energy expenditure (2,190 ± 629 vs. 2,462 ± 443 Kcal/day, p < 0.05). 31 out of the 50 HD patients (62%) had a mean daily value < 1.4 METs and hence were defined as sedentary. They differed from the active patients for higher age (63 ± 12 vs. 54 ± 12 y, p < 0.01), lower energy intake (26.1 ± 6.4 vs. 32.4 ± 11.3 Kcal/day, p < 0.05) and lower phase angle (5.5 ± 1.0 vs. 6.3 ± 0.9, p < 0.05). SWA-based estimation of daily energy expenditure was negatively related to age (r = -0.31, p < 0.05), whereas positive relations were observed with BMI (r = 0.51, p < 0.001), phase angle (r = 0.40, p < 0.01), serum phosphate (r = 0.49, p < 0.001) and albumin (r = 0.41, p < 0.01). The mean daily METs values were strongly related to normalized energy intake (r = 0.47, p < 0.001) and also to protein intake (r = 0.33, p < 0.05) and to phase angle (r = 0.38, p < 0.01). Multiple regression analysis showed that energy intake and dietary protein intake were independently related to the intensity of physical activity.

Conclusion: Our findings indicate that poor physical activity is highly prevalent in stable dialysis patients even when free from physical or neurological disabilities or severe comorbid conditions. The level and intensity of physical activity is positively related to body composition and to dietary nutrient intake. This confirms the strong interrelationship between exercise and nutrition, which in turn are associated with survival, rehabilitation and quality of life in dialysis patients.