Table 2.
Comparison of 24 h levels of sodium, potassium and creatinine measured in 24 h urine and predicted from spot urine with the Tanaka( 12 ) or Danish( 13 ) prediction method; women (n 118) aged 19–26 years, Wageningen, the Netherlands
| Measured 24 h urine | Tanaka prediction method | Danish prediction method* | ||||
|---|---|---|---|---|---|---|
| Mean | sd | Mean or Mean difference or Correlation coefficient | sd or 95 % CI | Mean or Mean difference or Correlation coefficient | sd or 95 % CI | |
| Na (mmol/d)† | 131·8 | 50·9 | 153·1 | 37·4 | 135·0 | 16·6 |
| Mean difference (mmol/d)‡, measured – predicted | – | – | −21·2 | −28·4, −14·1 | −3·2 | −10·9, 4·6 |
| Correlation coefficient§, measured/predicted | – | – | 0·64 | – | 0·62 | – |
| K (mmol/d)† | 66·8 | 24·8 | 53·2 | 12·5 | – | – |
| Mean difference (mmol/d)‡, measured – predicted | – | – | 13·6 | 9·9, 17·3 | – | – |
| Correlation coefficient§, measured/predicted | – | – | 0·58 | – | – | – |
| Creatinine (mmol/d)† | 11·7 | 2·2 | 12·5 | 1·7 | 11·2 | 0·8 |
| Mean difference (mmol/d)‡, measured – predicted | – | – | −0·8 | −1·2, −0·5 | 0·5 | 0·2, 0·9 |
| Correlation coefficient§, measured/predicted | – | – | 0·49 | – | 0·53 | – |
*
The Danish method does not provide coefficients to predict K.
†
Data presented are means and standard deviations.
‡
Data presented are mean differences with 95 % confidence intervals.
§
Data presented are correlation coefficients; all P<0·001 (two-tailed).