In this study, we attempt to evaluate the excess LOS related to hyperkalemia. Although
the raw difference of inpatients groups with or without the event is 8.8 days, the part of
the difference that is imputable to hyperkalemia ranges from 2.3 to 6.0 days, and most
of the methods tested here evaluate this difference around 4.4 days after outliers’
deletion. The excessive estimation of 8.8 days is due to an artifact: a high LOS exposes
the patient to various time-dependent adverse events, including hyperkalemia. We can
surely say that the raw difference overestimates the LOS difference, but this study does
not allow for deciding which method is true. The real difference is probably in the
interval [2.3; 4.6]. On one hand, the regression methods may still overestimate the real
LOS difference because the coefficient of determination is still low (less than 35% in
every case)