Purpose: Discussions about advanced directives are often delayed in chronic obstructive lung disease (COPD). An important barrier to discussing a “Do-Not-Intubate” (DNI) directive may be uncertainty about whether its harms would exceed its benefits given particular patient preferences and particular settings. To inform shared decision making, we asked when individualized harms of endorsing “DNI” would exceed individualized benefits.
Methods: We constructed a decision analytic model comparing QALYs endorsing versus not endorsing a “DNI” advanced directive. The analysis time horizon was infinite, and the decision epoch was 1 year (as this decision is typically reevaluated on an annual basis). Probabilities, utilities, and life expectancies were based on published estimates or expert opinion, and data were pooled where appropriate using the random effects method of Der Simonian and Laird. We considered different patient preferences regarding permanent institutionalization, one of the main potential harms from not endorsing “DNI”, and different setting-specific complication rates. We stratified underlying disease severity into three categories, mild, moderate and severe COPD based on the validated BODE index.
Results: For patients with low severity COPD, endorsing a DNI advanced directive decreased quality-adjusted life years from 19.57 QALYs to 19.12 QALYs, a difference of 0.45 QALYs. DNI was not preferred even when we varied each variable across its plausible range, and even when the utility of permanent institutionalization was equal to death (0). For patients with severe COPD, endorsing a DNI directive decreased QALY from 1.36 to 1.31, a smaller decrease of 0.05 QALYs. DNI became the preferred advanced directive when the utility of being in a nursing home decreased below 0.19, and also was preferred when the probability of endotracheal tube (ETT) complications increased to ≥0.6; the yearly probability of having a severe exacerbation increased to ≥0.8; or the probability of surviving a complicated ETT decreased to ≤0.3.
Conclusions: For patients with severe COPD, endorsing a DNI advanced directive improved QALYs in select circumstances, most notably when patients had strong preferences against permanent institutionalization, or if setting-specific outcomes were poor. Future work may include improving the model to inform shared decision making and decision aid development.
Candidate for the Lee B. Lusted Student Prize Competition