demographic

##             Variable            Summary
## 1                age   66.6 + 12.5 (22)
## 2           gender_0     16/22 (72.7 %)
## 3           gender_1      6/22 (27.3 %)
## 4             race_3      3/22 (13.6 %)
## 5             race_4     18/22 (81.8 %)
## 6             race_6       1/22 (4.5 %)
## 7        ethnicity_0     19/22 (86.4 %)
## 8        ethnicity_1      3/22 (13.6 %)
## 9                bmi    27.6 + 5.6 (22)
## 10  dialysis_vintage 889.8 + 920.5 (10)
## 11          access_0       1/21 (4.8 %)
## 12          access_1       2/21 (9.5 %)
## 13          access_2     10/21 (47.6 %)
## 14          access_3        4/21 (19 %)
## 15          access_4       2/21 (9.5 %)
## 16          access_6       2/21 (9.5 %)
## 17             cad_0     12/22 (54.5 %)
## 18             cad_1     10/22 (45.5 %)
## 19              dm_0      9/22 (40.9 %)
## 20              dm_1     13/22 (59.1 %)
## 21             chf_0     14/22 (63.6 %)
## 22             chf_1      8/22 (36.4 %)
## 23             htn_0       2/22 (9.1 %)
## 24             htn_1     20/22 (90.9 %)
## 25             pvd_0     20/22 (90.9 %)
## 26             pvd_1       2/22 (9.1 %)
## 27 Net.Fluid.Balance 1670 + 1220.9 (22)
## 28           race2_4     18/22 (81.8 %)
## 29       race2_other      4/22 (18.2 %)
## 30         access2_2     10/21 (47.6 %)
## 31     access2_other     11/21 (52.4 %)

Finger measure

## [1] 0.4670751
## 
## Call:
## lm(formula = Finger.delta ~ Net.Fluid.Balance, data = dat1)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -170.72  -75.71  -35.32    6.12  552.42 
## 
## Coefficients:
##                    Estimate Std. Error t value Pr(>|t|)  
## (Intercept)       -80.02290   57.62437  -1.389   0.1802  
## Net.Fluid.Balance   0.06633    0.02808   2.362   0.0284 *
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 157.1 on 20 degrees of freedom
## Multiple R-squared:  0.2182, Adjusted R-squared:  0.1791 
## F-statistic: 5.581 on 1 and 20 DF,  p-value: 0.02841

Leg measure

## [1] 0.0675898
## 
## Call:
## lm(formula = Leg.delta ~ Net.Fluid.Balance, data = dat1)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -87.657 -32.929   4.419  29.696  72.468 
## 
## Coefficients:
##                     Estimate Std. Error t value Pr(>|t|)
## (Intercept)       -16.845464  16.317229  -1.032    0.314
## Net.Fluid.Balance   0.002409   0.007951   0.303    0.765
## 
## Residual standard error: 44.48 on 20 degrees of freedom
## Multiple R-squared:  0.004568,   Adjusted R-squared:  -0.0452 
## F-statistic: 0.09179 on 1 and 20 DF,  p-value: 0.765

Finger measurement is significantly correlated (r=0.47, p=.028) with net fluid balance; Leg measurement is not associated with net fluid balance.

Subgroup analysis

## [1] 0.5223434
## 
## Call:
## lm(formula = Finger.delta ~ Net.Fluid.Balance, data = subset(dat1, 
##     Net.Fluid.Balance > 2))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -176.17  -61.51  -18.06   16.76  525.16 
## 
## Coefficients:
##                     Estimate Std. Error t value Pr(>|t|)  
## (Intercept)       -120.37064   68.71277  -1.752   0.0968 .
## Net.Fluid.Balance    0.08301    0.03194   2.599   0.0181 *
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 154.5 on 18 degrees of freedom
## Multiple R-squared:  0.2728, Adjusted R-squared:  0.2324 
## F-statistic: 6.754 on 1 and 18 DF,  p-value: 0.01814

Using Net.Fluid.Balance > 2 (I am not sure about the unit), the correlation is stronger. Note only 2 subjects’ Net.Fluid.Balance is less than or equal to two.

## [1] 0.183363
## 
## Call:
## lm(formula = Leg.delta ~ Net.Fluid.Balance, data = subset(dat1, 
##     Net.Fluid.Balance > 2))
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -82.794 -32.869   7.386  30.190  78.010 
## 
## Coefficients:
##                     Estimate Std. Error t value Pr(>|t|)
## (Intercept)       -29.019997  20.218770  -1.435    0.168
## Net.Fluid.Balance   0.007437   0.009398   0.791    0.439
## 
## Residual standard error: 45.47 on 18 degrees of freedom
## Multiple R-squared:  0.03362,    Adjusted R-squared:  -0.02007 
## F-statistic: 0.6263 on 1 and 18 DF,  p-value: 0.439

Leg measurement is not associated with net fluid balance.