Table 2B

Variables predictive of mortality for T12 model

Beta-coefficient from lasso
 Private insurance onlyReference group
 Medicare only0
 Combination of any insurance including Medicaid0.051
Oxygen therapy
 NoReference group
 Yes, continuously0.459
 Yes, nocturnal and/or with exertion0
 Yes, during exacerbation0
 Yes, prn0
 NoReference group
# of pulmonary exacerbations in the year preceding advanced stage CF diagnosis0.016
Interim change in FEV1 (T12–T0)
 Improvement >10% (+10%)Reference group
 Between −10% and 10%0
 Deterioration >10% (−10%)0.445
Interim number of pulmonary exacerbations (T0–T12)0.131
Lung transplant in the past 12 months
 NoReference group
  • Parameter estimates do not represent the true magnitude of effect. In other words, unlike in Cox regression models that use classical techniques of variable selection, exponentiation of the lasso beta-coefficient is not an estimate of the true HR. However, when taken in context of the model it can determine relative importance in prediction and positive or negative association with the predicted outcome.

  • *A negative value indicates predictive of lower mortality.

  • CF, cystic fibrosis; FEV1, forced expiratory volume in 1 s.