Correlation coefficient | p Value | |
---|---|---|

Best independent correlates from each domain | ||

Obesity | ||

Visceral adipose tissue volume by DXA scan | +0.50 | 0.001 |

Lung function | ||

FEV_{1}%, supine | −0.40 | <0.001 |

Sleep variables | ||

Mean overnight oxygen saturation | −0.50 | <0.001 |

Ventilatory control | ||

Ventilatory response to 15% oxygen | −0.28 | 0.02 |

Respiratory muscle strength | ||

Sniff maximum (cm H_{2}O) | −0.28 | 0.02 |

Hormonal, nutritional and inflammatory measures | ||

Vitamin D | −0.30 | 0.01 |

Cumulative correlation coefficient | p Value | |

Significant independent correlates | ||

Visceral adipose tissue volume by DXA scan | +0.49 | 0.004 |

Ventilatory response to 15% oxygen | +0.58 | 0.04 |

Results for the best correlates of BE in a linear regression for each individual domain. The correlate was chosen on the basis of the likelihood of it having a causal association with BE (eg, ventilatory response to 15% oxygen was chosen over the absolute fall in SaO

_{2}, and vitamin D was chosen over both BNP and transferrin). The lower part of the table shows the result for the best overall significant independent correlates of BE in a multiple linear regression containing the best correlate from each domain. A cumulative correlation coefficient of 0.58 indicates that the model accounts for 34% of the variance in BE. Vitamin D levels were the next most significant correlate, but with a p value of 0.19.BE, base excess; BNP, brain natriuretic peptide; DXA, dual-energy X-ray absorptiometry; FEV

_{1}, forced expiratory volume in 1 s.